Some readers may have heard of what is known as the summer and winter solstice. They primarily refer to the longest and shortest day of a calendar year, occurring at approximately the same time every year.

The longest day of the year is 21 June in the Northern Hemisphere and around 21 December in the Southern Hemisphere. The shortest day of the year occurs around 21 December in the Northern Hemisphere and 21 June in the Southern Hemisphere. They are known as the summer & winter solstice, respectively.

During two specific days of the year (and the days leading up to them), you will become aware of the terms "summer and winter solstice" frequently mentioned by people from all walks of life, and even see it covered extensively on television and read about it online.

These terms are also synonymous with the longest and shortest days of the year and when they occur in the Northern and Southern Hemisphere.

What is important from a weather perspective is the significance of these days as they relate to the changes in weather, as well as seasonality. This will also be the main focus of this article.

Before we can start to examine this relationship, we first need to define what exactly the summer and winter solstice is. 

What Is The Summer And Winter Solstice?

The summer solstice occurs on the longest day of the year, on 21 June in the Northern Hemisphere and around 21 December in the Southern Hemisphere. It is also commonly referred to as midsummer, the day the sun reaches its highest point in the sky.  

The winter solstice occurs on the shortest day of the year, usually around 21 December in the Northern Hemisphere and on 21 June in the Southern Hemisphere. It is also known as midwinter, the day the sun reaches its lowest point in the sky.

This is a very cryptic description of the complete process and what it implies, but it is the best explanation to make it quick and easy to understand.  

What Causes The Summer And Winter Solstice?

Most of you will know that the Earth is tilted on its axes. The direction in which it leans, as well as its rotation around the sun, is responsible for the summer and winter solstice.

In The Northern Hemisphere, around 21 June, the earth is tilted on its axes at 23.44° with the North Pole pointed towards the sun. On this day, the Northern Hemisphere gets the maximum amount of sunlight, and the North Pole experiences a day of constant sunshine.

During the winter solstice around 21 December, the North Pole faces away from the sun tilted on its axes at 23.44°. On this day, the Northern Hemisphere gets the minimum amount of sunlight, and the North Pole experiences a day of constant darkness.

In the Southern Hemisphere, exactly the opposite happens on these same dates, with 21 June being the shortest and 21 December the longest day.

Why Is The Longest Day Of The Year Not The Hottest And The Shortest Day Not The Coldest?

Naturally and understandably, you would think that the longest day in the middle of summer will also be the hottest on average. After all, this sounds logical and makes sense. Yet, as many of you would have noticed yourselves, this is never the case.

But why isn't the longest day of the year in the middle of summer not the warmest on average? Similarly, why isn't the coldest day of the year in the middle of winter not the coldest on average?

In the Northern Hemisphere, if you go to a beach resort or visit high-lying areas during June, you will notice that the beach is not that warm and the ocean water is still cold. In nature, some high-lying areas, specifically mountaintops, may still be covered with snow.

Visit these same areas two months later during August, and you will experience the warmest temperatures of the year. On average, the beaches will be hot and ocean water pleasant, and in nature, high-lying areas will now also be pleasantly warm with clear mountain tops.

What you are experiencing is called seasonal lag. And it is the seasonal lag that is responsible for this phenomenon that causes the warmest temperature to occur around two months after the summer solstice each year.

Seasonal lag is the occurrence where the highest temperatures in a location occur some time after the period of maximum solar radiation. The same applies to the area where the lowest temperatures occur some time after the period of least solar radiation.  

There is a simple explanation for the seasonal lag occurring every year, and it has everything to do with the different ways in which the various surface areas around the world warms up and cools down.

Although the air gets the maximum solar exposure during the summer solstice, the land and ocean water takes much longer to warm up (and cool down). Both land and sea get warmed, not only up to the summer solstice but for some period afterward.

Even though the amount of solar exposure is getting less after the summer solstice, the land and sea still receive solar radiation and keeps warming up. This is because the rate of heat absorption is still more than the amount of heat dissipating. 

Temperatures continue to rise until the rate of heat absorption is no longer more than the rate of heat dissipating. At this point, you experience the year's maximum average temperatures, which are approximately two months after the summer solstice.

The same process occurs in reverse during the winter solstice. After this day which receives the least amount of sunlight, the land and ocean waters are still releasing heat into the atmosphere for some period. This is because they also cool down much slower than the air.

Even though the amount of solar exposure is getting more after the winter solstice, the land and sea are still radiation heat and keeps cooling down. This is because the rate of heat dissipation is still more than the amount of heat absorption. 

Temperatures continue to fall until the rate of heat radiation from the land and ocean is no longer more than the rate of heat it absorbs. At this point, one experiences the year's lowest average temperatures, approximately a month or more after the summer solstice.

This phenomenon called seasonal lag clearly explains why the warmest and coldest days of the year occur some period after the summer and winter solstice, respectively. Once you understand seasonal lag, the whole process becomes much easier to understand.

Conclusion

You will now have a clear understanding of what the summer and winter solstice is and how they mirror each other in the Northern and Southern Hemisphere.

It should also explain that seasonal lag, due to the fact that the land and ocean take much longer to heat up and cool down, is responsible for the longest days not being the warmest, and the shortest days, not the coldest.    

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Most readers have seen a lightning strike during a thunderstorm in person or on a computer/television screen at some point. But what exactly is this phenomenon, how does it occur & what are its effects?

Even if you never personally experienced a lightning storm before, you most certainly would have seen it on television, online, or even in the movies. This is one of nature's most spectacular and potentially deadly displays.

The short summary above only provides a glimpse of what actually takes place between the different elements in the atmosphere to produce this powerful phenomenon. 

Few of us, however, know how this phenomenon occurs and what causes it. In this article, we look at what precisely lightning is, how it is formed, and examine other aspects of this powerful force of nature. 

What Causes Lightning?

We already know that lightning is basically a very rapid and powerful discharge of electrical energy. But what causes such a huge electrical current to form in the first place?

The answer lies in the movement of particles that are formed within a cloud. More specifically, the movement of ice crystals, graupel, and supercooled water.

After moist air has risen high enough to cool down and condensation takes place, cloud formation takes place. This process alone is not enough to produce lightning.

In a cloud where strong updrafts are present, water droplets are carried high up into the cloud formation, where it cools down to temperatures below freezing point. 

This usually occurs in a storm cloud like a cumulonimbus cloud, which is characterized by both extensive vertical development and strong updrafts.

As a result of the low temperatures combined with the strong updrafts, a mixture of ice crystals, graupel, and supercooled water can form.

Graupel is heavier than the much finer ice crystals. As a result, the lighter ice crystals are carried upwards in the cloud, while the heavier graupel starts to fall towards the ground.

(You can find out all about ice crystals and graupel and how they are formed in this article.)

When the rising ice crystals meet the falling graupel, a collision between the two takes place, and electrons are stripped off in the process. This causes the ice crystals to be positively charged, while the graupel receives a negative charge.

Negatively charged graupel now starts to accumulate at the bottom of the cloud while the top of the cloud gets saturated with positively charged ice crystals. In the early stage of this "electrification" of the cloud, the atmosphere act as an insulator between the two charges.

Video (courtesy of National Geographic) illustrating what a lightning strike is and how it occurs.

One lightning bolt alone can discharge up to one billion volts of electrical energy. To put this in practical terms, this is enough to power a 100-watt lightbulb for three months. This will explain why a lightning strike is able to light up the sky, even during the middle of the day.

The electrical discharge is not only powerful but also generates a lot of heat. In fact, a lightning bolt can heat up the surrounding air by up to 30 000° Celsius (54 000° Fahrenheit). This temperature is roughly five times hotter than the surface of the sun.

When people talk about a thunder and lightning storm, they are actually talking about the same occurrence. The thunder we hear during a lightning storm is nothing more than the sound generated by the discharge of electrical energy during a lightning strike.

This simply means that when we talk about thunderstorms or a thunder cloud, technically we are referring to a byproduct of a lightning bolt. For all intents and purposes, all these occurrences are lightning strikes.   

Types Of Lightning

Depending on what you read or who you talk to, there can be a long list of different types of lightning that occur under various circumstances. However, all lightning bolts that are the result of an electrical discharge in a cloud can be classified into three main categories:

1. Intracloud (IC) Lightning
2. Cloud-To-Cloud (CC or Inter-Cloud) Lightning
3. Cloud-To-Ground (CG) Lightning

Some of these three main types of lightning groups contain a variety of subcategories. While describing the lightning strikes that are characteristic of each main category, we will also take a look at a few of the more significant and noteworthy subcategories.  

1) Intracloud (IC) Lightning

Intracloud lightning occurs when an electrical discharge occurs between the positive and negative poles within a single cloud once the atmosphere can no longer act as an insulator between the two charges.

This is by far the most common form of lightning, accounting for roughly three-quarters of all lightning strikes. As a result, the majority of lightning never leaves a cloud system. 

It is also known as sheet lightning due to its ability to light up an entire cloud, giving it the appearance of a big white sheet with a bright light behind it.

2) Cloud-To-Cloud (Inter-Cloud) Lightning

Inter-Cloud lightning occurs when the electrical discharge occurs between the positive pole of one independent cloud and the negative pole of another independent cloud.

Like intracloud lightning, it is also known as sheet lightning due to its ability to light up an entire cloud system.

Intracloud and inter-cloud lightning are collectively called cloud flashes as the lightning occurs within and around a cloud system, lighting up the whole area for a split second.

3) Cloud-To-Ground (CG) Lightning

Cloud-To-Ground lightning is the form of lightning we are most familiar with and usually also produces the most spectacular display. This form of lightning occurs when the electrical discharge occurs between the bottom of the cloud and objects on the surface of the ground.

Usually, the negatively charged bottom half of the cloud is responsible for the surface of the ground below it becoming charged with positive ions. The positively charged area on the surface basically "follows" the storm cloud around.

Once the electrical poles become too strong, a powerful negative charge (called a step leader) shoots down and makes contact with a positively charged object on the ground (called a positive streamer) reaching up. 

When the two connect, a strong discharge occurs with a loud cracking sound. This causes a powerful and violent current, resulting in a return stroke, racing back to the cloud at 60 000 miles per second. The return stroke is the bright flash we observe as a lightning strike.

Effects Of Lightning

A bolt of electricity five times hotter than the surface of the sun, carrying up to a billion volts of electricity, and traveling at 60 000 miles per second, is bound to have a significant effect on any objects it comes in contact with on the ground.

Now take into consideration the fact that the earth gets hit by lightning a hundred times every second. That is eight million times per day. With so much power on display at such a frequent rate, its effects need to be taken very seriously.

Lightning can have a direct and indirect effect on objects, causing varying levels of injury and damage. This is a topic for another article, but here are just a few examples:

1) Direct Lightning Strikes

Although nine out of ten people hit by lightning survive, they may still suffer long-term injuries. This includes burn injuries, cardiac-related health issues, and damage to the nervous system. The same type of injuries can be applied to animals.

Vegetation also risks damage from a direct lightning strike. The rapid expansion of moisture can blow the bark off a tree. The heat from a strike can also cause forest fires, and the instant heating of water in a rock can cause it to shatter.

Infrastructure can also be seriously damaged by lightning. It can shatter concrete, bricks, and stone, causing severe damage to buildings. A direct strike can also destroy all electrical equipment within a structure. 

2) Indirect Lightning Strikes

Electrical and electronic equipment is very vulnerable to an indirect lightning strike. Hitting a nearby substation or power-line can cause a dramatic surge in your electricity supply, potentially damaging or completely destroying electrical/electronic equipment. 

Indirect Lightning can still be fatal. It is pure electricity, and any surface it hits can carry the electric current. In 2016, over 300 reindeer were killed by lightning that hit and traveled through the ground. This is also why it is so dangerous to stand underneath a tree during a lightning storm.

Conclusion

This article detailed what these spectacular lightning displays are that one sees captured on video, television, or experienced in real life. It also assisted in better understanding how this powerful phenomenon is created or formed in the first place.

But one will also be able to understand the power that lightning possess and the potential danger that comes with it. There is nothing wrong with admiring this wonder of nature, but neither is having a healthy dose of respect for it. 

Never miss out again when another interesting and helpful article is released and stay updated, while also receiving helpful tips & information by simply  clicking on this link .

Until next time, keep your eye on the weather!

Some weather enthusiasts may be unfamiliar with Chinook (or Föehn) winds, but they are simply variations of the same meteorological phenomena known as the orographic effect. We take a closer look.

Chinook winds are warm, dry winds that blow down the eastern slopes of the Rocky Mountains through a process called the orographic effect. As moist air from the Pacific Ocean rises against the western slopes, it cools & causes precipitation. The dry air warms as it descends down the eastern slopes.

If you live in an area surrounding the region that commonly experiences these winds, you may be familiar with the names. But what exactly are Chinook winds, and how do they develop in the first place?

Chinook winds got their name from the Chinook Native American people who lived in coastal areas near the Columbia River (in the States of Washington and Oregon), where these winds occur on a regular basis. 

Föehn winds originate from the German word "Föhn," which literally means hot, dry wind. It is in this region of the Alps in Central Europe where this occurrence was first studied.

Although these winds have different names, depending on the region where they occur, they are exactly the same weather phenomena, no matter where they form in the world.

What Are Chinook And Föehn Winds?

As just stated, the first thing to know about Chinook and Föehn winds is that they are essentially the same type of wind. You may not be aware of it, but the area you live in or one nearby may regularly experience these air movements on a seasonal basis.

By providing a quick summary of what Chinook winds are, and then giving a more detailed description of the Föehn winds they are based upon, one will be able to get a clear understanding of what these type of winds are an how they are created.

As already mentioned in the introduction, Föhn (Föehn) winds were first identified and studied in Central Europe's Alps.

The name "Chinook" simply refers to the Native Americans who lived in the region where this phenomenon frequently occurs but are essentially nothing more than Föehn winds.

The process through which a Föehn wind develops follows the same steps, no matter where they are found throughout the world:

How Chinook And Föehn Winds Develop

As moist, warm air blows and reaches the windward side of a mountain, it starts to ascend against the mountain slopes. As it gains altitude, the air also starts to cool down.

Once the air reaches a height where the air has cooled down enough for condensation to take place, precipitation in the form of rain and snow follows. In the process, the air loses most of its moisture, while the condensation also allows for the release of latent heat.

(As contradictory as it may sound, condensation is known as a warming process, and evaporation as a cooling process. To make more sense of these seemingly opposing statements, you can find detailed a more detailed explanation in this article.)

As the air reaches the mountain top, it is now both dry as a result of the precipitation and slightly warmer due to the release of latent heat during the condensation process.  

It now starts it descend down the leeward side of the mountain. As the air continues to move downward, the effects of gravity force it to speeds up and become warmer as it continues to accelerate down the slopes towards the bottom of the mountain.

The mass of descending air also has a significant effect on the heating process. As the large volume of air descends, it causes the air to compress. The descending mass of air causes so much pressure that it results in the air heating up, a process called adiabatic heating.

All these steps and processes combined result in a warm, dry wind of considerable strength, known as Chinooks, Föhns. 

Regions situated on the leeward side of a mountain experiencing this phenomenon usually experience warmer and more pleasant weather conditions in a cloudless sky.

This process is also commonly known as the orographic effect (or orographic lifting). Find out more detail about this process and how it works in this article.

Effects of A Chinook And Föehn Winds

The warm and pleasant weather experienced by areas in Central Europe parts of Northwest America as a result of these winds is not the only effect they have on the environment.   

1) Melting And Evaporation Of Ice

The warm and dry nature of these winds resulted in the name "ice-eaters," due to their ability to melt and even evaporate ice before it can melt. A strong Föehn wind is able to make a layer of 30 centimeters (12 inches) of snow "vanish" within a day.  

2) Loss Of Ground Water

The intensity of some Chinook wind occurrences can lead to exposed losing a large percentage of its moisture. It has been reported that wind gusts from a Chinook wind can exceed speeds of 120 km/h (75 mph). This can have a widespread negative effect.

Ingeniousness vegetation naturally will suffer as a result, but it has an even larger impact on the agricultural sector, where crop losses can impact the local economy. 

3) Effects On general Health

Several debates are ongoing around the real health effects of Chinook/Föehn winds. It seems the most significant discussion revolves around the issue of whether these winds have a real health impact or are just perceived as such by people who are "affected."

However, there seems to be consensus over the general health effects of this phenomenon. This applies to both the positive and negative impacts of Föehn winds.

On the positive side, the people whose lives are severely inhibited by freezing conditions find their lives easier to manage, as their daily activities are made simpler. Their bodies can cope much better under warmer conditions.

A general feeling of well-being has also been documented, but it's unclear whether it is a result of the relief mentioned in the previous paragraph or if the warmer weather and clear skies directly trigger these emotions.

(The clear skies allow sunlight through, which helps to generate vitamin D in the body, which is responsible for the release of endorphins.)

On the negative side, Föehn winds are connected to the migraines many people are experiencing during the occurrence of this phenomenon. So much so that these migraines are often referred to as Chinook headaches.   

Less serious and related effects have also been documented, but many of these have not been substantiated or enough research is done.    

Conclusion

After reading this article, the "shroud of mystery" should have been lifted over the foreign-sounding Chinook and Föehn winds.

These winds also have many other names, mostly related to the region where they occur. In South Africa, they are commonly known as a Bergwind, in California the Santa Ana, in Argentina the Zonda winds, and in Slovenia the Fen. 

The examples mentioned in the previous paragraph are just a few examples of a number of local names used for the same phenomenon. 

So rest assured, the Chinook or Föehn winds you experienced first hand or just heard about are just local names given to a normal phenomenon experienced throughout the world. 

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Atmospheric temperatures generally drop as altitude increases above the Earth's surface, as many of us have experienced. But during a phenomenon known as temperature inversion, the opposite occurs.

Temperature Inversion is a meteorological phenomenon that occurs when temperatures rise as altitude increases within a layer of air. This contrasts with the typical characteristics of the atmosphere, which usually shows a drop in temperature as altitude increases.

Temperatures continue to fall as altitude increases. It roughly drops by 9.8° Celsius every 1000 meters (5.4° Fahrenheit every 1 000 feet). Most of us experienced this occurrence at some point during our lives, when on the roof of a tall building or hiking up a mountain.

There is a phenomenon, however, that turns this norm on its head by causing an increase in temperature with height. It is called Temperature Inversion.

We take a closer look at what a temperature inversion is, what causes it, and its impact on the weather and environment.

This phenomenon can occur in a fixed position like the stratosphere, where the temperature naturally rises with height. 

(The average temperature in the stratosphere starts at -51° Celsius (-60° Fahrenheit) above the troposphere, and rises to an average of -15° Celsius (5° Fahrenheit) close to the mesosphere.)

Temperature inversion also takes place in pockets or layers of air throughout the atmosphere caused by different variables. These layers are not so easily predictable and can have a dramatic impact on the weather and environment.

Causes And Types Of Temperature Inversion

This section will focus on the different variables that cause the inversion layers that appear randomly throughout the atmosphere. Temperature inversion is primarily caused by four different factors, resulting in four types of inversion:

1) Surface Inversion

This form of temperature inversion usually takes place on a cloudless night with little or no wind present, creating the perfect conditions for heat to escape rapidly from the surface.

As a result, the air at the surface cools down much more quickly than the air above it in the atmosphere, creating a low-lying temperature inversion.    

2) Frontal Inversion

Colder air is denser and heavier than warmer air, which means a cold front is also heavier and thicker than a warm front.

When the two fronts meet, the lighter and warmer air from the warm front is lifted up by the cold and dense air from the cold front, resulting in warm air on top of a layer of cold air.

Unlike the other forms of temperature inversions, a frontal inversion takes place much higher up the atmosphere, as the size and steep gradient of the cold front allow the warmer air to be raised up to higher altitudes. 

To find out more about warm and cold fronts and their characteristics, you can read more about them in this article.

3) Subsidence Inversion

This form of temperature inversion is a direct result of the pressure caused by huge masses of air. When these large volumes of air start to descend, it compresses the air within the layer, which leads to an increase in temperature.

It also has the added effect of slowing the speed at which temperature change takes place (lapse rate). If this layer of warm compressed air continues to descend, it causes the air higher up in the atmosphere to be warmer than the air closer to the surface.

4) Topography

The topography of the surface can also be responsible for the creation of a temperature inversion. A good example of this form of inversion is the one that takes place at night in the valley between hills or mountains.

When it cools down in the evening, the surface of the slopes on the hillside (or mountain peaks) cools down quicker than its surroundings, causing the air above it also to cool down. The colder air starts moving down the slopes and accumulates at the bottom of the valley.

As the colder air moves into the valley, it lifts the warmer air at the bottom up and away from the surface. This leaves the valley with colder air at the surface and warmer air higher up in the atmosphere.

The Effects Of Temperature Inversion

Due to the "unnatural" nature of temperature inversion, some unexpected and extreme conditions are created as a result of this phenomenon. Some of these results can be seen as potentially harmful and dangerous. The most important ones are:

1) Freezing Rain

Under normal conditions, when ice crystals combine to form snowflakes in subzero temperatures, it falls to the ground and stays intact as it falls through colder air as it nears the surface.

With an inversion layer present, though, the snow melts as it falls through the warmer air. When it exits the layer, it does not have enough time to freeze again, but the temperature in the raindrops continues to drop to below freezing point, creating supercooled water.

This is called freezing rain, and as soon as these cold raindrops hit the surface, they are immediately turned into ice. This is extremely dangerous, as the thin layer of ice that is formed is almost invisible and extremely slippery.

When this ice forms on the surface of roads or pavements where people walk, it makes these surfaces very slippery and almost impossible to spot. This is referred to as black ice and is a major cause of accidents on and off the road in countries frequently experiencing this weather phenomenon.

(Learn more about freezing rain and how it differs from sleet in this article.) 

2) Sound Amplification

A temperature inversion also has the effect of amplifying sounds below it. It as acts as a giant reflective ceiling under which all sound generated is refracted down.

This means sounds can travel further and sound much louder than it really is. For example, it has been extensively reported that thunderstorms sound much louder when an inversion layer is present.

Man-made occurrences like the sound of a passenger aircraft, explosions, and other loud sounds appear to sound louder and can be heard further away.

3) Smog   

Probably the most important and dangerous consequence of temperature inversion is the trapping of smog and other toxic gasses in a densely populated urban environment or metropolitan area.

Due to the infrastructure and the heat generated by transport and other human activities in a city, heat is absorbed and maintained, only to be slowly released in the atmosphere above the city at night and during cold winter months.

This creates a layer of temperature inversion covering the city. This inversion layer acts as a seal that traps smog, warm air, and other toxic emissions in the city.

This not only creates a serious environmental problem but also poses a dangerous and potentially life-threatening situation by keeping these gases from escaping and trapped on the surface and lower atmosphere.

Carbon dioxide, smog, carbon monoxide, and lead are just a few of the chemicals trapped below the inversion layer. All these chemicals have severe and long-term effects on human health and mortality.

You can read all about The Urban Heat Island effect, what causes it, and its effect on the weather and environment in this article. 

Conclusion

After reading this post, you will have a much better understanding of what Temperature Inversion is and how it is bucking the trend of meteorological norms.

To be honest, though, as the weather is starting to show some startling and peculiar trends during recent years due to more than a hundred years of reckless human interference, it may not stand out as rebellious or unanticipated on its own for much longer.

For now, one needs to understand the causes and dangers of temperature inversion in order to make sure we prevent similar disruptive weather trends from getting established, expanding, and becoming the new norm. 

Never miss out again when another interesting and helpful article is released and stay updated, while also receiving helpful tips & information by simply  clicking on this link .

Until next time, keep your eye on the weather!

Evaporation & condensation are two crucial meteorological processes that are essential for the formation of different weather patterns. We examine the two occurrences and their impact on the weather.

Evaporation is the process through which water and other substances are changed from their liquid state into their gaseous state. Condensation occurs when water and other substances are changed from their gaseous state back into their liquid form.

One can almost go as far as stating that very few weather events, if any, will be able to take place without at least one or both of these processes playing a significant part.

This will soon become clear to you when you see these activities at work, creating different weather conditions.

First, we need to get a clear understanding of what precisely evaporation and condensation are before continuing to look at their individual roles in weather creation:

Defining Evaporation And Condensation And The Differences Between Them

Probably without even realizing it, the vast majority of readers have already seen examples of both evaporation and condensation at work.

If you ever saw the steam rise from the boiling water in a kettle or walked into a steam-filled bathroom with steam rising from the hot bathtub, you experienced evaporation.

Similarly, if you ever noticed the dew on the grass when leaving your house in the morning or saw the dewdrops on your car, which stood outside throughout the night, you have seen the results of condensation.

Essentially, evaporation and condensation are two sides of the same coin. They both involve a substance in its liquid or gaseous form, changing from one to the other. 

What Is Evaporation?

Evaporation is the process through which a substance is changed from its liquid state into a gaseous state, mainly due to a rise in temperature but also as a result of a decrease in atmospheric pressure.

Evaporation typically occurs at the surface of a body of water when rising temperatures cause it to turn into water vapor.

What Is Condensation?

Condensation is the process through which a substance changes from its gaseous state back into a liquid state, mainly due to a drop in temperature or when the saturation level of the air exceeds the amount of moisture it can carry.

When water vapor (water in its gaseous state) is cooled down beyond its dew point, or the air is saturated to the point where it can't contain any more water vapor in the air, condensation takes place. In the atmosphere, this typically leads to the formation of clouds.

Now that one established what each process entails, we can examine the effect they have on the weather and related events.

How Evaporation And condensation Affect The Weather?

As mentioned in the introduction, evaporation & condensation play a vital role in the formation of weather, and without it, the creation of weather is virtually impossible.

Earlier, It was also mentioned that they are two sides of the same coin, which was already partly explained in the previous section when both processes were defined in more detail.

Although they each have their own roles to play, together, the two are part of an overarching process called The Water Cycle.

The Water Cycle

The Water Cycle (Hydrologic Cycle) can best be described as Earth's Big Recycling System. It is the process through which water is moved between the land, ocean, and atmosphere. 

One can view it as Nature's fine balancing act, making sure the land does not get dehydrated or oversaturated with water. The same process occurs in the planet's oceans simultaneously by making sure seawater levels remain at roughly the same height throughout the year.

The water cycle can best be described by breaking it down into its four steps: 

1. Evaporation and Transpiration: The ocean water, as well as inland bodies of water, get heated up by the sun, which causes the water at the surface to evaporate. The leaves of plants and trees also release moisture into the air through a process called transpiration. Both processes cause water vapor to escape and rise up into the atmosphere.
   
2. Condensation: As the water reach air continues the rise, the temperatures start to drop and cool down the air. This leads to condensation taking place and clouds formed as a result. Air movement in the atmosphere can cause clouds to form above or at a completely different location from where they evaporated.  
3. Precipitation: As the air continues to be saturated with water vapor, more water droplets are formed and grow in size. The clouds are no longer able to hold the moisture, and precipitation takes place. (This can be in the form of rain, snow, hail, or even sleet.)
4. Runoff and Groundwater Absorption: The rain falls on surfaces of various heights. The force of gravity makes sure the water finds its way into natural runoff areas like streams and rivers. They end up flowing back into the ocean or bodies of water from where they evaporated. Some of the water also gets absorbed by the soil through a process called infiltration, which helps to replenish and maintain Groundwater Tables.

As you can clearly see, evaporation and condensation play a critical part in The Water Cycle. Each one also has a unique effect on its environment and certain weather events, which we will have a look at in the next section.  

Does Evaporation Affect The Weather?

One now have a good idea of what evaporation is and the role it plays in The Water Cycle. It also has a few other specific attributes and weather conditions associated with it.

Evaporation is often called a Cooling Process. You won't be blamed for being more than a little confused after reading this contradictory statement. After, all it is the heat of the sun that warms up the surface water and causes it to evaporate.

It takes energy, in the form of heat, for water vapor to form above the surface of a body of water. For the water vapor to rise, it must take the heat energy with it. As heat is taken away from the surface, the remaining air is cooled down. Hence the Cooling Process.

Evaporation on a large and intense scale can also result in one of the most devastating weather events on earth. When the warm waters of the Subtropics are exposed to extensive heating, large-scale evaporation occurs. This can trigger a tropical storm, which can quickly turn into a hurricane or cyclone.

It is clear what will happen when a hurricane or cyclone makes landfall. To find out more about hurricanes and cyclones, as well as their devastating effects, you can read the in-depth article here.

How Does Condensation Affect The Weather?

Like evaporation, you now have a good idea of what condensation is and the role it plays in The Water Cycle. And like evaporation, it also has a few other specific attributes and weather conditions associated with it.

In contrast to evaporation, condensation is referred to as a Heating Process. This can be confusing and seen as a contradiction as well since condensation is the result of a drop in temperature and colder conditions in general. 

For water vapor to return to its liquid form, it has to lose some of its heat energy. Once enough energy has been released, water vapor turns into water droplets. In the process, heat is released into the atmosphere, causing it to heat up. Hence the Heating Process.

When condensation takes place in a moisture-heavy cloud system constantly being fed by fresh moisture, the result is heavy and consistent downpours. This is exactly what happens during the summer monsoon season in India and Southeast Asia.

Southerly winds are continuously driving the moisture-filled clouds into the subcontinent during the summer months. The condensation leads to frequent and heavy downpours, which cause flash-flooding throughout the warm season, resulting in multiple fatalities and large-scale damage.

You can read more about monsoons, how they are formed, and their effect on the environment in this article. (Look towards the end of the article under the "monsoons" section.)

Condensation also results in a variety of cloud formations, which are visible indicators of the kind of weather to expect. You can read all about the different cloud formation and what it each one means in this article.

Conclusion

If it was unclear to you before, you should now have a good understanding of what exactly evaporation and condensation are, and how each process takes place.

Even more importantly, you will realize just how critical both these processes are in the formation of almost every weather event.

Never miss out again when another interesting and helpful article is released and stay updated, while also receiving helpful tips & information by simply  clicking on this link .

Until next time, keep your eye on the weather!

Local weather conditions may often differ slightly from broader regional weather. But an Urban Heat Island, commonly experienced in cities and densely populated areas, is something entirely different.

An Urban Heat Island is a densely populated city or area that is substantially warmer than the surrounding region. The higher temperatures are mainly a result of urban infrastructure and human activity. Temperatures are generally higher throughout the day but are most noticeable during the evening.

The term "Urban Heat Island" may not be that familiar, but anyone living in a city or densely-populated already experienced this phenomenon. And unlike other atmospheric conditions, this localized weather occurrence is entirely the result of human activity. 

(We already discussed the difference between local and regional weather in detail in a separate article. You can read more about these differences in this article.)

The term is not used to describe a certain size area in which weather conditions are reported, but rather a space created by human activity, which created its own microclimate.

Before looking at how this phenomenon occurs and what its impact is, one first needs to define what an Urban Heat Island is.

Infrastructure (concrete buildings, glass & asphalt roads) is the primary contributor due to its ability to maintain and trap heat within this environment. This is also why the difference in temperature is wider during the night than during the day. 

The second-largest contributor to Urban Heat Islands is human activity, like the heat produced by transportation (buses, cars, and trains), the heating of homes, and the heat generated by human bodies and respiration.  

Now that you have a clear idea of what an Urban Heat Island is, we can drill down into the specifics to find out how this microclimate is created.

Causes Of The Urban Heat Island

We already identified the main factors responsible for the formation of a UHI (Urban Heat Island). But to see how exactly these factors create this effect, they need to be examined in more detail. 

1) Infrastructure

Infrastructure can be considered as the primary cause of the UHI effect. The majority of a city is covered by concrete, asphalt, glass, and metal.

The attributes of concrete and asphalt allow them to absorb and maintain heat throughout the day and well into the night. This makes the temperatures in the city significantly higher than the surrounding rural area.

Reflective materials like glass and metal allow heat to be reflected and scattered onto the already warm concrete, asphalt, and other heat-absorbent materials in the city.  

2) Transport

As a city has a high concentration of humans living and working in a relatively small area, a higher volume of transportation is required.

This means more buses, cars, and trains which all make use of heat-generating engines. The sheer volume of transportation in a city, it will quickly make it obvious how much extra heat is generated and contributing to the UHI effect. 

3) Respiration And Emissions

To a lesser extent, our own bodies are also a source of heat in more than one way. In this section, we will just focus on our respiration. The air we inhale is warmed up by our bodies, causing the air we exhale not only to be more toxic but also much warmer.

A similar process occurs with internal combustion engines used by buses and motor vehicles. The air escaping through each vehicle's exhaust also produces toxic, but more importantly, heated air.       

4) Lack Of Vegetation

The one thing rural regions have in abundance that metropolitan areas don't is vegetation. And it's vegetation that helps the environment to cool off throughout the day. Plants and trees absorb carbon dioxide and release fresh oxygen-rich air into the atmosphere. 

But of more importance is the evapotranspiration (evaporation and transpiration) process. The process involves soil in between vegetation, treetops, as well as plant leaves themselves, releasing moisture into the atmosphere, which has a significant cooling effect.

Traditional metropolitan and other densely populated urban areas contain almost no or very little vegetation. In contrast, the urban surface contributes to heating rather than cooling the surrounding air, as is the case when plenty of plants and trees are present.

5) Urban Canyon (Street Canyon) Effect

The streets and alleyways spread throughout the city and flanked by tall buildings, create a flow of air similar to that present in a canyon, hence the name, "Urban or Street Canyon."

This occurrence greatly contributes to the UHI effect. The tall buildings inhibit the free flow of air through the city, causing the heat generated by the city's infrastructure to be trapped in the air above the streets and between the buildings.

There are many other factors also contributing to the creation of the Urban Heat Island Effect, but the ones just mentioned play the biggest part. 

Features And Effects Of An Urban Heat Island

During the description at the beginning of the article, the heat difference caused by a UHI and the rural surrounding was mentioned. By looking at the characteristics of an Urban Heat Island, you will be able to better understand how exactly it functions.

1) Difference In Temperature

The air of a metropolitan area is not just much warmer than the surrounding rural areas, but the temperature difference also does not stay the same throughout the day (24 hours).

During the evenings, the difference in temperature is much larger than during the day. The average yearly difference in temperature between metropolitan and rural areas is around 1–3° Celsius (1.8–5.4° Fahrenheit) during the day.

During the evenings, though, the average yearly difference in temperature can increase to  12° Celsius (22° Fahrenheit). The big difference in nighttime temperature is mainly due to the way in which the surface areas cool down.

Here, two familiar factors have the greatest impact:

a) Urban Infrastructure

The concrete, asphalt, and reflective materials that cause metropolitan areas to heat up more than rural areas, also maintain the heat and radiates the warm air well into the night, causing the city to remain warm.

The tall buildings also prevent vital air movement, trapping the heat inside. The normal current of upward moving the air when the surface is heated, called convection, usually removes warm air from the surface. This process can not take place in this environment.

b) Lack Of Vegetation     

The benefits of vegetation and its ability to cool down rural areas have already been explained in detail. The lack of vegetation in densely populated urban environments and metropolitan areas further diminishes these areas' capability to cool down effectively.

(City planners are realizing this shortcoming, and modern cities are designed to incorporate "green zones" which contain dense sections of green vegetation. Any area that can be further utilized to accommodate plants and trees is increasingly being used. 

Rooftop gardens are one such case where the roofs of buildings are converted into living gardens rich in leafy plants, grass, and trees. The cumulative effect of incorporating vegetation throughout the city can make a huge impact on effectively cooling it down.)

2) Accumulation Of Photochemical Smog And Other Toxic Gases  

Unfortunately, not only the warm air but all the pollutants and toxic gases produced within the UHI are also trapped in this "Urban Heat Dome." This has a negative effect on both human health and the environment.   

The brown haze you see hanging over a city, normally early in the morning or late afternoon, is called Photochemical Smog. Photochemical Smog forms when ultraviolet rays of the sun react with nitrogen oxides (gases produced by the burning of fossil fuels).

This is not the only pollutant hazardous to human health that accumulates in the air within an Urban Heat Island. Carbon dioxide is a greenhouse gas that is not only harmful to humans but also contributes to global warming and climate change.

Carbon dioxide is produced by the burning of fossil fuels (primarily through transport emissions, but also through the burning of wood and coal.) To find out more about carbon dioxide and its wide-ranging effects, you can read the full article here. 

Ozone levels are also raised due to photochemical interactions created by the UHI. Ozone, which is crucial gas for protecting the earth from the sun's harmful UV radiation, is the cause of a range of respiratory problems when coming into direct contact with humans. 

A range of other harmful pollutants is also present in the air, which is unable to escape due to the UHI effect. These include sulfur dioxide, dust particles, lead, hydrocarbons, and carbon monoxide.

3) Impact On Bodies Of Water And Pollution

Indirectly, the warm air even affects the water quality of bodies of water in or near the Urban Heat Island. Water that ends up in rivers, ponds, and dams, starts its journey far away from where it ends up.

As rain falls in a metropolitan area that is experiencing the UHI effect, the raindrops fall on warm rooftops, pavements, and streets. They run down warm drainpipes before being collected by drains and carried away by stormwater runoffs.

The water can travel for miles before reaching a river, dam, or pond. It has been determined that the UHI effect can warm the rainwater from 21° Celsius (70° Fahrenheit) all the way up to 35° Celsius (95° Fahrenheit).

Aquatic life is very sensitive to changes in water temperature, and an influx of warm water can be devastating, endangering the livelihood of many fish and other aquatic species.

A further danger comes from standing water with warm temperatures. These types of conditions are ideal for deadly waterborne diseases to develop and spread, helped along by the carcasses of dead aquatic creatures and excrement. 

Especially in rural communities that rely on water from rivers and reservoirs close to the city, people are very exposed to the deadly diseases that can spread under these conditions. 

You can learn more about these waterborne diseases that are the main cause of fatalities in India during the Monsoon season (which are also a result of standing warm water) in this article. Look towards the end of the article under the "Monsoon Section."

4) Direct Impact Of Elevated Temperatures On Human Life

The first and most important characteristic of an Urban Heat Island is the elevated temperature. It is the much warmer conditions that have the most profound effect on human health and well-being.  

This is particularly obvious during summer months when the UHI effect causes the highest temperatures to be recorded. During this period it is people with developing and weakened immune systems to be most prone to be affected by heat-related diseases.

Children and the elderly fall into this group. Children (and adults) can easily suffer from heatstroke, headaches and dizzies, cramps, and respiratory problems. Although very few of them are fatal, these conditions have now been linked to long-term organ damage.  

People, especially the elderly, with existing health conditions like asthma, diabetes, and cardiovascular disease, are especially hard hit by the increased temperature.

Every year, the rate of fatalities has shot up during periods of high temperatures, especially among the elderly. And this is a worldwide phenomenon, especially in Western Societies where urbanization and concentrated metropolitan areas are developing at a record rate.

Conclusion

There should be no doubt left in your mind that the Urban Heat Island Effect is very real, and its impact on the environment and human health is much bigger and more significant than anyone expected it to be.

Although not on such a large scale, the UHI also has a small but significant impact on global warming and climate change, as well as the UHI's immediate surroundings. 

The difference between the microclimate of Urban Heat Islands and nearby rural areas can be so significant that many people are turning to home weather stations to measure the atmospheric conditions in their surroundings.

You can read more about why you may need the convenience and the added assurance of a home weather station in this article.

I trust you now have a clear and thorough understanding of what an Urban Heat Island is, how it is created, and the effects it has on the weather and its surroundings.

Never miss out again when another interesting and helpful article is released and stay updated, while also receiving helpful tips & information by simply  clicking on this link .

Until next time, keep your eye on the weather!

El Niño is a series of unusual weather patterns caused by the warm Pacific Ocean deviating from its normal flow and accumulating at the South American west coast. La Niña forms when water flows towards the Southeast Asian coast, resulting in an upwelling of cold water near the South American coast.

In recent years, the term "El Niño" started surfacing in weather forecasts and the news as a result of its widespread impact on global weather, specifically the resulting droughts in some parts of the world. Inevitably, its counterpart, "La Niña," also started getting attention.

So what is the difference between these two "interestingly" named phenomena, and how do they affect the weather to such an extent that we as humans get impacted as a result?

To answer this question, we have to take a look at what specifically each one is, how it is formed, and the effect it has on the weather. 

El Niño Defined

What Is El Niño?

El Niño can be summarized as a series of unusual weather patterns and events that are caused by the warm waters of the Pacific Ocean that deviate away from its normal flow. 

Instead of compounding close to the Southeast Asian coast, as is usually expected, the warm waters flow eastwards around the equator and accumulate near the northwestern coastline of South America. This has a profound effect on the weather.

Needless to say, there are specific factors responsible for triggering this effect.  

What Causes El Niño?

We already established that the El Niño phenomenon is a direct result of warm water being pushed in an easterly direction to accumulate against the northwestern coastline of South America.

What causes these waters to change direction in the first place is a weakening or change in the direction of trade winds. Approximately every 3 to 5 years, the strength of the trade winds is substantially diminished or even reversed.

Under normal conditions, the waters along Southeast Asia will be warmer than the much colder waters pushing up along the west coast of South and Central America.

During El Niño years, however, the warm water is now pushed in an easterly direction, canceling the effect that the warm waters off the east coast of Southeast Asia and the cold waters off the west coast of South America would have had under normal conditions.

The typical, contrasting warm and cold temperatures between the coastlines of the two continents are greatly diminished. With the heat largely evened out between the two continents, the warmest waters are now situated near the center of the Pacific Ocean.

As ocean temperatures are one of the main drivers of weather, the El Niño phenomenon leads to drastic weather changes on a global scale, as you are about to learn.

(Warm ocean water is responsible for some of the most extreme weather events on the planet. You can find out more about how warm water triggers these events in this article.)

The Effects Of El Niño On The Weather

If you regularly read other articles about the weather, you will know that the weather is a very complex system, influenced by countless variables that result in weather patterns and conditions on a local and global scale.

The El Niño effect is no different. It has an immediate impact on the global climate, but also a longer global effects on weather patterns. 

The warm and moist waters along the South and Central American West Coast cause the creation of a much wetter climate in the region. Countries like Paraguay, Brazil, Argentina experience more extended periods of intense precipitations.

Southeastern parts of the United States and Mexico also experience higher volumes and longer periods of rainfall due to the same warm and humid ocean waters. An increase in extreme weather events is also triggered by the warm waters in the East Pacific.

As mentioned, El Niño also has a long-term effect on global weather patterns. The change in water temperature affects the major wind currents in the upper atmosphere. It is these major wind currents that have a profound effect on the weather systems worldwide.

Some regions experience a wetter short-term climate change, with extended periods of precipitation and more extreme weather events. Many areas around the world, however, are experiencing much drier weather conditions, as rain-bearing weather systems are now being moved away from these regions.

Regions like Southern Africa, Australia, Indonesia, and India are subjected to prolonged periods of dry conditions during this period. This has led to droughts being declared in some of these countries. 

Although the El Niño cycle occurs typically every three to five years, it appears at irregular intervals, making it hard to forecast. It can last anything from nine months to two years. (To be classified as an El Niño effect, the warming has to last for a minimum of nine months .)

The reason why this is important is that the dry spells and droughts in the affected countries are amplified by the impact of Global Warming.

The compounding effect of both El Niño and Global Warming is causing an increased intensity and prolonged duration of the dry weather. This is having severe economic and humanitarian consequences for many of these countries.

La Niña Defined

What Is La Niña?

La Niña can be summarized as the weather and climate patterns that are formed as the result of warm water being shifted further away from the west coast of South America in the direction of the Southeast Asian coast. 

This causes colder than usual water to rise up near the west coast of South America. As a result, the Central and Eastern Pacific Ocean is a few degrees colder than usual.

In the same manner as El Niño, the change in temperature also has a significant effect on global weather and climate.

La Niña can be seen as the counterpart or opposite of the El Niño phenomenon. The weather created is just very different from that of the El Niño effect, which is a result of the much colder water temperature. (More on this shortly.)

Now that we have a clear and brief idea of what La Niña is, it is important to look at how precisely it is formed and which factors are involved. 

What Causes La Niña?

During average years, warm water accumulates near the Southeast Asian coast, while colder water is brought to the surface in the Central and Eastern Pacific Ocean through a process called upwelling.

(Upwelling is the process through which colder water is brought to the surface as a result of surface winds and ocean currents.)

During La Niña years, though, abnormally strong trade winds have a significant impact on the westerly movement of warm ocean water. The stronger winds force large portions of warm water to shift and end up near the Southeast Asian coast.

As warm water is removed off the west coast of South America, more cold water is forced to the surface. As a result, the temperature of the Central and Eastern Pacific Ocean waters is substantially lower than usual.

La Niña usually occurs every three to five years, although it can be very inconsistent and last for extended periods. 

A period of La Niña can be officially declared if a temperature drop of 3 to 5° Celsius (5.4 to 9° Fahrenheit) below the norm is observed for a period of at least five months in the Central and Eastern Pacific Ocean. 

As I previously mentioned, ocean temperatures are one of the main drivers of weather, which means the La Niña phenomenon also leads to drastic weather changes on a global scale, just the El Niño effect.

The Effects Of La Niña On The Weather

There is a reason why La Niña is called the counterpart of El Niño. The weather conditions created by the phenomenon are almost the direct opposite of those created by El Niño.

Due to the much colder water near the South American coast, the lack of moisture in the air is restricting cloud formation in the area, which leads to dry weather conditions in western South America and southern parts of the United States during La Niña years.

Mainly due to its negative association with Global Warming, many readers will be familiar with carbon dioxide. We take a closer look at this gaseous substance and its impact on the weather and climate.

Carbon dioxide is a naturally occurring gas consisting of one part carbon and two parts oxygen. It is typically harmless and essential for oxygen production through photosynthesis. However, excess carbon dioxide due to fossil fuel emissions acts as a greenhouse gas contributing to Global Warming.

Carbon dioxide is a gas that has been in the atmosphere for thousands of years but has only been brought under the public's attention late in the 20th Century when the connection between fossil fuel emissions and Global Warming was made.

Yet, few of us really know what precisely carbon dioxide is, never mind the role it plays in our environment. The excerpt in this introduction already provided a brief description of what carbon dioxide is, but before delving deeper, one needs a more detailed definition.

Carbon dioxide is essential for all life on earth. Luckily there is an abundance of it present in the atmosphere. Unfortunately, too much carbon dioxide has a damaging effect on both the climate (and weather) as well as our health.

As mentioned in the introduction, it is because of the alarming rate at which carbon dioxide is building up in the atmosphere and its harmful longterm effects, that we are so familiar with it in the first place.

Understanding the harmful effects of carbon dioxide is important for you to get a proper understanding of what "all the fuss is about" and why certain groups of people go to extremes to reduce the emissions of this greenhouse gas.

Therefore, shining a light on these harmful effects will be the focus of this article. To get a clear understanding of the negative impact of carbon dioxide buildup, we need to break it up into two sections:

1. How carbon dioxide affects the climate and weather
2. The effects of carbon dioxide on human health

Obviously, the emphasis will be on the impact of carbon dioxide on our climate and the weather. These changes in our environment alone will also have far-reaching effects on human health.

The direct effect of exposure to carbon dioxide on human and animal life will only serve to reinforce the severity of the impact of carbon dioxide buildup. 

The Effect Of Carbon Dioxide On The Climate And Weather 

There is a very fine balance between carbon dioxide (CO₂) and the atmosphere. If concentration levels of carbon dioxide become too high, like is currently the case, the impact on the atmosphere can be devastating.

And like meteorologists and climatologists have been warning and providing evidence for decades, it is the climate and weather that are being affected the most.

In short, the effects of carbon dioxide in the atmosphere are increasingly amplified as carbon dioxide concentration levels increase. This is directly reflected in our climate and weather.

By looking at how it directly affects individual components of weather/climate, you will be able to get a clear and realistic view of the widespread impact raised levels of carbon dioxide have and how all these different components fit together to create a global crisis.

a) Carbon Dioxide And Global Warming

During the article's introduction, I already called carbon dioxide a greenhouse gas, but no further explanation was given as to what a greenhouse gas is.

First, if you don't already know this, let's quickly define what a greenhouse gas is. The name "greenhouse" refers to a building typically found in nurseries and other facilities where plants and trees are grown.

A greenhouse's main purpose is to regulate the inside temperature to promote plant growth, primarily through transparent roofs and sidewalls that allow direct sunlight in but trap the heat inside by blocking any openings to allow warm air to escape.

Carbon dioxide is called a greenhouse gas because it serves the same purpose of blocking warm air from escaping the earth's atmosphere. It accomplishes this through its ability to stay in the atmosphere on a semi-permanent basis and trap the warm air below.

Its semi-permanent attributes is a result of the ability of the structure of this gas to not get broken down by changes in temperature (on a physical or chemical level).

As a result, it makes it increasingly difficult for warm air to escape, causing the atmosphere as a whole to slowly warm up.

And this process is known as global warming, which is based on the same principle a greenhouse operates on. This also explains why global warming is often referred to as the greenhouse effect.   

As the name suggests, the rise in temperatures occurs across the globe but is especially evident in the polar regions. Throughout the rest of the world, regional record-high temperatures are being recorded on an almost annual basis.  

With the sheer amount of research done and mountains of scientific evidence presented to us over the last couple of decades, there is no denying it. Global warming is very real and continuing to pose an increased danger to all life on Earth.

And if, for some reason, you still question all evidence that the planet is warming at an alarming rate, consider the following small fact...

Since 1906, the global surface temperature increased by 0.9° Celsius (1.6° Fahrenheit). And if you think this is a small and insignificant number, you will be gravely mistaken.

The effects of Global Warming have very serious, long-term effects on climate and weather, as you are about to discover in the following sections.

b) Climate Change And It's Link To Carbon Dioxide

It is very common to mistake climate and weather. In short, climate represents weather patterns and tendencies established over decades or more, while weather portrays the atmospheric conditions you are experiencing at any specific time and what is forecasted for the immediate future.

You may still find it difficult to differentiate the two and need more clarification. You can read an in-depth article about the difference between climate and weather in this article.

When we look at climate change, however, this term encompasses more than just atmospheric conditions. Climate change also includes occurrences associated with weather/climate, like changes in the environment and behavior associated with it. 

But for climate change to take place, especially at the alarming it is suggested, it relies on one critical factor, namely global warming. Without the consistent artificial heating of the planet, climate change simply won't be possible.

We already established that global warming is very real, and so is climate change. The evidence of climate change is all around us, from increased extreme weather events to droughts occurring worldwide.

Making a statement like this may sound like pointing out the obvious to many readers. To more critical readers, however, this may sound a bit like unsubstantiated claims.

Even though more evidence of climate change will be provided in upcoming sections, it's important to point out some key indicators to highlight the existence and impact of climate change...

1) Rising Sea Levels

Sea levels have been rising steadily for more than a century. This can be seen as a direct result of global warming. Since 1880, the global sea level has risen by about 23 cm (8 inches).

What is most unsettling, though, is the fact that 7.6 cm of this rise took place during the last 35 years! It means the rate at which these levels continue to rise is accelerating every year.

2) Extreme Weather Events

The increase in extreme weather events is becoming more evident with each passing year. We will cover these events in more detail in a later section, but here are just a few examples from 2018 alone.

• The highest temperature ever in Africa was recorded at 51° Celsius (124° Fahrenheit) in Ouargla, Algeria. 
• Extensive flooding due to unusually high rainfall in Japan led to 155 lives lost, while approximately five million people were instructed to evacuate their homes.
• The United States experienced Hurricanes Florence and Michael, two of the most destructive hurricanes in the country's history. Meanwhile, Typhoon Mangkhut caused mass destruction in Hong Kong and the Philippines.
• California in the United States experienced the most destructive series of wildfires in the State's history due to the persistent dry conditions and searing heat. This led to a loss of 85 lives.

We will cover extreme weather events and their link to climate change a little later on.

3) Contracting Of The Ice Sheets

Ice sheets have been shrinking across the world throughout recorded history, but the rate at which they have been contracting has accelerated over the last couple of decades.

For example, from 1993 to 2016, Greenland experienced an average loss of 286 billion tons of ice every year. During the same period, Antarctica experienced a loss of 127 billion tons of ice every year.

Like the accelerated rise in sea level, it is the increasing rate at which ice is melting that is so disconcerting. In Antarctica alone, the rate at which ice has been melting has tripled in the last 10 years.

4) Receding Glaciers

Glaciers in Scandinavian and other countries near the Arctic Circle are beautiful features that attract visitors from across the world every year. Many of these frozen "rivers of ice" are literally thousands of years old!

The "toes or snouts" are the end of a glacier and called the terminus. And it is the terminus that gets the hardest hit by the warmer climate, causing them to melt and the resulting water to either run of to the sea or forms lakes at the edge of the glacier.

This "receding trend" has been going on since the start of the twentieth century, and glaciers have been retreating at an alarming rate ever since. This is happening in all the areas famous for their glaciers, including the Himalayas, Mount Kilimanjaro, the Alps, The Rocky Mountains, and parts of the Andes.

The accompanying picture of the Briksdal glacier in Norway (taken in 2003 and then again in 2008) is a perfect illustration of how climate change is contributing to the recession of glaciers worldwide.

5) Snow Cover

Over the last five decades, a decrease in snow cover has been observed over the Northern Hemisphere. This is especially evident during the springtime (March and April).

Not only is the overall snow cover less, but it also started to melt earlier in recent years than it did during previous years. The most rapid declines were observed during June each year.

This is very significant, as a third of the world is covered in snow for parts of the year. As the white-colored snow reflects the sun's radiation away from the planet's surface, it shielded the surface from being heated by the sun.

With less snow present to reflect the heat away, larger areas of the surface are now exposed to absorb the heat, which contributes to global warming and accelerates climate change. 

These are just five examples used to highlight the reality and impact of climate change.

Climate skeptics will still question whether climate change is as real and threatening as the scientific community makes it out to be. 

The following trends are direct consequences of carbon dioxide buildup and, and as a result, climate change. This will help to reinforce the validity of climate change and the dangers associated with it.

c) Acid Rain Due To Carbon Dioxide Bonding

In the atmosphere, many gases and small dust and pollen particles bond with moisture in the clouds that falls to the ground as rain. Carbon dioxide is no different and also bonds with rain droplets in the air.

The more CO₂ that is present in the air, the more acidic is the composition of the raindrops in a cloud system. Although this "acid rain" is not acidic enough to have any short-term effects, it has some serious and damaging long-term effects.

Acid rain is causing freshwater sources like dams and rivers to turn acidic, endangering the livelihood of fish species in it. Tree and plant life are also threatened as acid rain leaches aluminum from the soil. 

The acid also removes vital nutrients and minerals from the soil, which are needed by plants and trees to grow and survive. As a result, it is not uncommon to see dying trees and plants in areas that are affected by acid rain.  

d) Ocean Acidification Caused By Increased CO₂  

By now, there shouldn't be any doubt left that a surplus of carbon dioxide exists in the atmosphere, and more are still being added by the burning of fossil fuels.

Its damaging effect through global warming is already seen on a worldwide scale. What makes it worse, though, is the fact that its presence is not just limited to the atmosphere.

A quarter of the CO₂ released in the atmosphere is absorbed by the planet's oceans. Over the last few decades, the addition of CO₂ is slowly changing the chemistry of seawater, which poses a serious problem. This process is called ocean acidification.

As the name suggests, carbon dioxide is making the water more acidic. This causes a variety of problems for certain fish species, like respiratory problems, compromised immune systems, and the depression of metabolic rates.

The acidic water also has a dramatic effect on coral reefs through a process called coral bleaching. The coral turns white and can completely die off. This is devastating for marine life using it as a habitat to live it in, as well as those using it as a source of food.  

We as humans heavily rely on the oceans to provide us with a constant supply of food, so indirectly, this will have a long-term effect on us as well.

e) Increase In Extreme Weather Resulting From CO₂ Buildup

If you haven't been hiding under a rock lately, you will be well aware of how extreme weather events like hurricanes, cyclones, and tornadoes are increasing every year at an alarming rate. 

We already touched on this subject earlier in this article, but these events are such clear indicators of a climate shifting and changing direction at a rapid rate that they need to be emphasized again.  

What may be even more alarming is the fact that carbon dioxide can cause extreme weather events without having to wait for the effects of global warming to start kicking in. This study was reported in the June 2018 issue of "Nature Climate Change."

In short, the assumption is that global warming occurs proportionally to the amount of carbon dioxide in the atmosphere. During the study, however, it was discovered that releasing a high amount of carbon dioxide caused an immediate spike in extreme heat in the specific area. 

This means carbon dioxide triggers extreme weather either directly or indirectly through the effects of global warming.

f) Carbon Dioxide Responsible For Less Cloud Formation

Yes, you did read this heading right. More conclusive proof is being presented to indicate that an increase in carbon dioxide levels can be linked to a reduction in cloud formation.  

So far, no natural occurrences or evidence of high levels of CO₂ breaking up clouds have been observed. This is a theory that was successfully tested by researchers from Caltech by running simulations on a supercomputer.

Lead scientist, Tapio Schneider, theorized that high enough concentrations of carbon dioxide could break up stratocumulus clouds. As I already stated, this hypothesis was successfully proven in theory. 

Although this is still just a (proven) theory, it has potentially huge implications for cloud formation in the future as carbon dioxide levels continue to rise. Only time will tell...

We really ventured far and wide, and sometimes strayed far away from the main topic of carbon dioxide. But if you look carefully, you will see that carbon dioxide is closely involved, either directly or indirectly, in each and every topic discussed in this article.

We just spend an enormous amount of time looking at all the ways carbon dioxide is involved and affects our climate, weather, and environment.

It will be incomplete and irresponsible not to spend just one section to look at carbon dioxide and its affect on human health directly.

Effects Of Carbon Dioxide On Human Health

Carbon dioxide is a naturally occurring gas which, at normal levels, is necessary for maintaining life on earth. 

The emphasis here is normal levels. Just as is the case with the climate and environment, CO₂ becomes dangerous and unhealthy to humans once it starts building up and becomes more concentrated, reaching toxic levels.

This can lead to serious health complications. One of the first signs of high levels of CO₂ is respiratory problems, starting with difficulty in breathing. Other symptoms include dizziness, headaches, sweating, and an increased heart rate.

More serious conditions are characterized by convulsions, asphyxia, and being comatose.

Carbon dioxide poisoning is probably one of the most serious conditions as a result of too much CO₂ in the bloodstream. This is a very serious condition that can be life-threatening and requires immediate emergency medical care.

This is not the place to try and provide any medical information. The purpose of this section is to make you aware of the dangers of high levels of carbon dioxide and how serious any symptoms should be taken.

Conclusion

This was a comprehensive article covering a variety of ways in which carbon dioxide contributes to global warming and climate change in direct and indirect ways.

It will be surprising if you don't feel a bit overwhelmed and confused by all the information. You may have to back and reread sections of the article you need to understand better.

To help you better make sense of the key points about carbon dioxide highlighted in this article, here is a summary of everything contained in this article in a few bullet points:

• Carbon dioxide, at normal levels, is a natural and safe gas that forms part of the earth's atmosphere.
• It is an essential gas necessary for the survival of plant and tree life, which produces carbohydrates which are necessary to sustain life on earth.
• Carbon dioxide levels are elevated and becoming highly concentrated through natural processes, but mainly as a result of human activities like the burning of fossil fuels.
• It is a greenhouse gas, which at elevated levels means it is blocking heat from escaping the atmosphere, contributing to global warming.
• Global warming is responsible for climate change which is considered by many to be the biggest danger faced by humankind.
• There is concrete evidence of global warming and climate change, from rising sea levels to extreme weather events. 
• Carbon dioxide has been shown to play a role, direct and indirectly, in both global warming and climate change.
• CO₂ by itself is also dangerous to human health in elevated levels and high concentrations.

I hope this will help you get a better understanding of carbon dioxide, what it is, and the role it plays in global warming and climate change.

Never miss out again when another interesting and helpful article is released and stay updated, while also receiving helpful tips & information by simply  clicking on this link .

Until next time, keep your eye on the weather!

Today, there is no shortage of choice when it comes to choosing a thermometer, from the trusty old mercury thermometer to modern-day digital sensors. But centuries ago, measuring the air temperature was performed by devices such as the Galileo thermometer.

A Galileo thermometer is a meteorological instrument consisting of a sealed glass tube filled with a clear liquid containing small glass bulbs of varying densities. Ambient temperature changes also alter the liquid's density, causing different bulbs to rise or fall, which indicates the temperature.

Although this specific thermometer as we know it today wasn't designed by Galileo himself, all the principles that the thermometer is based upon were discovered and implemented by Galileo Galilei and his thermoscope.

Galileo Thermometer Definition

Before delving into the inner workings, though, we first need to define what precisely a Galileo Thermometer is:

Each bubble is partially filled with a different colored liquid. Small metal tags of different weights are also hanged below each bulb to adjust their "density," while each tag also contains a number.

Any changes in air temperature change the density of the liquid as well. This causes the bubbles inside the liquid to rise and fall in response to changes in the fluid's density.

By observing the different heights at which the glass bubbles are floating, the temperature can be determined. This is done by identifying the number of the tag below the bubble floating at the "right height."

If this sounds confusing to you, you are not alone. If I only described to you what a Galileo thermometer looks like and how it responds to temperature changes, it would be difficult to understand what is really happening and why.

One needs to understand the principles and forces at work that make all the parts in this thermometer behave the way they do and how they all work together to help determine the atmospheric temperature.

The first priority, therefore, is to make sure every principle is fully explained and understood. And that will be the focus of the next section.

(If you are familiar with these principles or want to skip all the technical jargon, you can jump over the next section and move directly to the section explaining how a Galileo Thermometer works.)

The 3 Principles Of A Galileo Thermometer

In order to better understand how a Galileo Thermometer works, one first needs to clarify three principles to make sure you understand how they influence the individual components that form part of the thermometer:

1. Buoyancy: Many explanations of the Galileo Thermometer start by emphasizing the fact that the instrument works on the principle of buoyancy. 
2. Density: The Galileo Thermometer is named after the scientist, mainly because it is based on his formulation of the principle that the density of a liquid changes in proportion to its temperature.  
3. Gravity: Gravity plays a major role in the downward pull of all objects. This is especially important for the Galileo Thermometer to operate correctly.

So which one of these three principles is the Galileo Thermometer based on? Actually, all three principles play an equally important part in making it work.

The best way to understand the relevance and importance of all three principles is to see how each one works and its role in making the Galileo Thermometer work.

1) Buoyancy

Buoyancy is the upward force or thrust of a liquid on an object submerged in it. It is the very principle that all vessels designed to float on top of the water are based upon.

It is very closely related to the principle of density. Density is probably the most significant factor that determines an object's buoyancy.

A simple example will illustrate how this works in practice. Take a tennis ball or football, and try and push it underwater in a bucket or bathtub. What happens?

It immediately starts resisting your action and shoots to the surface as soon as you release it. This is because the density of the air in the ball is so much less than that of the water.

Now try and do the same with a heavy piece of metal like lead. You will immediately notice that you do not experience any "pushback" from the water while you submerge it.

If you release it, the piece of lead drops to the bottom. The metal's density is so much greater than that of the water that the "upward force" of the liquid has very little effect on the lead's downward movement.  

As you just observed, the density of an object compared to that of the liquid, it is submerged in determines its buoyancy (ability to float).

2) Density

Although the original inventor/s of the Galileo Thermometer is unknown, it is named after the legendary scientist due to his discovery that the density of a liquid responds to changes in temperature.

The Galileo Thermometer may be a much more complex instrument, but it is based on the thermoscope that Galileo invented as a result of his theory.

Although most of us understand what density is, it is a bit harder to define in words. ScienceDaily.com puts it best by describing "density as mass per unit of volume."

This means the density is closely related to an object's mass. But mass has to be put in context by equating it to its volume (physical size).

Technically, density can be calculated by dividing mass by its volume.

This is best understood by seeing in practice. Let's use the example of a piece of iron of a certain size. Now compare that to a piece of foam of exactly the same size.

Clearly, the piece of iron is much heavier than the foam. This is because it has a much higher density than the similarly sized foam.

We can easily prove this by using the equation to calculate density: Density = mass/volume.

Let's say the piece of iron weights 2000 grams (4.4 pounds) and the foam weights 200 grams (0.44 pounds). We already know they have the same volume (size), for example, 20 square centimeters (0.31 square inches).

Do the calculation, and you will see that iron has a much higher density of 100 cm³ compared to the 10 cm³ of the same size foam.

Simply put, if two solid objects of the same volume have different weights, the heavier object has a bigger density.

3) Gravity

Gravity is the Earth's force that pulls all objects in the atmosphere towards its center, regardless of the mass and shape of the object. The strength of the gravitational pull on an object is described as its mass.

Gravity impacts every single object on earth. Every one of you is aware and experiences gravity every single every day (sometimes in a very unpleasant way, especially when you lose your balance and fall from a considerable height).

It should come as no surprise then that gravity plays a vital role in the functioning of a Galileo thermometer. It is the constant battle between density and gravity that determines the glass bubbles' buoyancy in a liquid-filled tube.

Now that all the principles and forces at work have been explained and are out of the way, it is time to see how they all work together to make a Galileo Thermometer work.

How Does A Galileo Thermometer Work?

From the description earlier in this article, you already know what a Galileo Thermometer looks like and what it consists of.

What you may not realize is that each of the colored glass bubbles in the liquid is approximately the same density. It is the numbered metal tags hanging below each bubble, that changes the "density" of each globe.

The individual tags each have a different weight that corresponds to the number on them, which shows the specific temperature each glass bubble represents.

From the previous section's explanations, you will also know that it is the density of objects in a liquid that determines its ability to float (their buoyancy). And it this very principle that makes a Galileo Thermometer works.

Each glass globe in the thermometer has a different density. Some bubbles are the same density of the water they are submerged in at a specific atmospheric temperature. The other globes all have different densities (read mass), varying from slightly to substantially lighter or heavier than the density of the water.

It is important to remember that air temperature directly influences the density of water. If the temperature increases, it warms up the water, making it less dense. If it decreases, the air cools down the water, making it less dense.

The glass globes inside the liquid respond to this change in the water's density. Some bubbles that are now less dense than that of the water will start to rise to the top. At the same time, the bubbles with a density lower than that of the water will begin to sink to the bottom of the tube.

The glass bubbles, which now have the same density as the surrounding water, will be floating around halfway between the ones at the bottom and the ones at the top. These glass bubbles in the middle are the ones that show the actual air temperature at the time. (As indicated by the number on the tag).

And that is how the Galileo thermometer works. It is a simple-looking process, but as you have learned, with a lot of different forces at work behind the scenes.

As the air temperature keeps changing, the glass globes continue to change their height in the liquid to adjust to the water's density.

Conclusion

Although not being used for meteorological purposes anymore, it is easy to see why Galileo Thermometers are still so popular. They are not just beautiful to use as ornaments, but the constant movement of the glass globes inside the water makes them fascinating to watch.

It also helps that, despite its fairly rudimentary and dated mechanisms, it is still surprisingly accurate compared to modern state-of-the-art thermometers.

You can find out more about specific Galileo Thermometers and other interesting meteorological instruments in this article.

Never miss out again when another interesting and helpful article is released and stay updated, while also receiving helpful tips & information by simply  clicking on this link .

Until next time, keep your eye on the weather!

Weather enthusiasts may have heard of a storm glass, also known as weather glass or a weather globe. But what is this meteorological instrument, where did it originate from, and how does it work?

A storm glass is a meteorological instrument used in the 19th century to predict the weather. It consists of a sealed glass tube filled with chemicals dissolved in distilled water. Weather predictions were based on the amount of crystallization and fogginess that occurred within the liquid.

They may have different names but are all one and the same thing. They come in a variety of shapes and sizes. Many also come with different colored liquids, as they are mostly used for ornamental purposes nowadays.

A little more than a century ago, these instruments were considered serious meteorological devices that were widely used to predict the weather. It became especially popular in Britain during the mid-1800s. (More on its history a little later in this article.)

A Short History Of The Storm Glass

For some reason, the real inventor of the storm glass is unknown. What we do know, however, is that a British naval officer by the name of Admiral Robert FitzRoy is the man responsible for making it famous.

Admiral FitzRoy was a keen weather enthusiast, and during his time aboard the HMS Beagle, he did numerous experiments with the storm glass and carefully documented all his findings.

As a strong believer in the capabilities of the storm glass, Admiral FitzRoy promoted its use throughout the United Kingdom to help meteorologists make better weather forecasts, especially after a storm in 1859 caused hundreds of fatalities at sea.

Since the more accurate barometers of the time were too expensive for mass production, the British Crown ordered large numbers of storm glasses to be delivered to coastal towns and maritime communities throughout the British Islands.

At the time, storm glasses became commonly known as "FitzRoy's storm barometers."

During the late 1800s, mercury barometers became much affordable. As a result, storm glasses started to lose their popularity. 

They also proved to be much less accurate than originally thought, which contributed in no small part to their demise in the meteorological community. 

How Does a Storm Glass Work?

Before taking a closer look at how a storm glass works, one first needs to define this meteorological device formally:

Actually, the question in the heading should be whether a storm glass works at all instead of how it works. And the answer all depends on who you ask. To get a clearer picture, one needs to take a closer look at how it is supposed to work.

If Admiral FitzRoy were alive today, he would be able to provide you with an extensive chart detailing "with certainty" how different changes in the storm glass correlates with specific future weather events.

As previously mentioned, the chemicals mixed into the distilled water of a storm glass have a clear appearance. Under certain atmospheric conditions, the liquid starts to crystallize and take on a foggy appearance.

FitzRoy used the different stages of crystallization and fogginess that occur in the liquid as weather conditions change to establish a pattern and draw up an extensive forecast chart.

In the diagram below, you will be able to see what characteristics in the storm glass Admiral FitzRoy associated with which weather conditions. The state of the liquid is displayed in the left column and the predicted weather conditions in the right column of the diagram:

The various states of the liquid and the predicted weather conditions associated with them (as shown in the diagram above), are the conclusions of Admiral FitzRoy. It has not been substantiated by any recent research or studies.

In truth, not enough research and studies have been done to reach a definitive conclusion as to exactly how a storm glass works and how accurate it really is.

Unfortunately, enough studies have been done to confidently state that a storm glass has at best a 50 percent chance of accurately forecasting the weather.

During FitzRoy's time, storm glasses were not able to be completely sealed due to the limitation of the technology of the time. As a result, a change in barometric pressure could have played a role in his findings.

Modern-day storm glasses are completely sealed. This means the only atmospheric variable that can really play any part in the changes occurring in a storm glass is temperature.

The effect temperature has on the liquid inside a storm glass can not be accurately measured or used to produce any kind of legitimate weather prediction. 

Conclusion

Even though storm glasses didn't turn out to be the meteorological wonders they were once thought to be, they still remain fascinating and an interesting talking point among weather enthusiasts and even meteorologists today.

As I already mentioned, storm glasses are still produced and used today, but not for any serious meteorological work. Today they serve a more ornamental purpose, which is why they come in many interesting shapes, sizes, and colors.

They actually make an aesthetically pleasing addition to any study, studio, or bookshelf display, and it is still fascinating to observe how the liquid within the glass crystallizes under different weather conditions.

If you are interested, you can find out more about the different modern-day examples of storm glasses available by following this link.

Never miss out again when another interesting and helpful article is released and stay updated, while also receiving helpful tips & information by simply  clicking on this link .

Until next time, keep your eye on the weather!