WHAT ARE THE EFFECTS OF GLOBAL DIMMING?

Global dimming is the gradual decrease in the amount of solar energy reaching the earth’s surface. It occurs due to increased particulates in the atmosphere. These particles block the heat and light from the sun, causing a cooling effect on the planet. Global dimming is also known as solar dimming.

FACTS ABOUT GLOBAL DIMMING

There has been a big drop in the amount of solar radiation that gets to the surface of the earth. (Research from Encyclopedia.com)

• Global dimming was first measured in the 19th century. However, Benjamin Franklin, an American experimenter, first talked about this in the 18th century.
• Measurements made between the early 1960s and the 1990s had some interesting finds. The findings show a big drop in the amount of solar energy that reaches the planet’s surface.
• Human activities are the main cause of global dimming. Pollution is the main source of most of the particulates in the air above the Earth.
• The dimming cools things down on earth, which is not good for the world. The cooling hurts ecosystems and causes other problems. 
• Global dimming has different effects on different parts of the world. Solar radiation can be different in different areas of the world. There is a lot of evidence that the northern hemisphere is the worst.
• Data showed a 4 to 8%  drop in the amount of solar energy that reached the Earth between 1961 and 1990. People in the southern hemisphere aren’t as affected by global dimming as people in the northern hemisphere.
• The effects of global dimming are the opposite of global warming.

CAUSES OF GLOBAL DIMMING

Global dimming happens when there are too many particles in the air. Tiny liquid droplets or solid particles called aerosols are the main cause for concern. They are also called “atmospheric particulates.”

These compounds can be released into the air by natural or man-made processes:

1. Burning of Fossil Fuels

• Harmful compounds form when fossil fuels like coal and oil are burned. Carbon dioxide is the main danger. However,  other particles are also made during the process of burning something, like wood or paper.
• Sulfur dioxide, ash, soot and other things pollute the air. It is easy for these airborne aerosols to get into the upper atmosphere.
• With time, these small particles build up in the earth’s atmosphere, making it darker. This causes global dimming.
• Gradually, there will be more particulates in the air. This will cause more solar energy to be reflected out into space.

2. Volcanic Eruptions

• Active volcanoes can erupt from time to time.  Volcanic eruptions are bad for the environment because they release dangerous gasses into the air.
• Sulfur dioxide (SO2), hydrogen sulfide (H2S), water vapor (H2O), hydrogen halides, and carbon dioxide are some of the gasses volcanoes make (CO2).
• SO2 and H2O have been shown to cause global dimming, which makes the sky look dark.
• CO2, on the other hand, is to blame for the rise in global temperatures.
• Solar energy can be absorbed by the ash made when volcanoes erupt. Ash may also be spread out in the air.

3. Wildfires

• Wildfires are more common because of the rise in global temperatures. Fires start in most parts of the United States and Australia every year.
• Wildfires, like volcanoes, send greenhouse gasses and smoke into the air. The thick smoke from wildfires can block the sun for a short time. This blocking of the sun causes low temperatures.
• Smoke particles can also make clouds more reflective.  It may take time for the smoke from wildfires to go away. However, the clouds have long-term effects on areas around fires.
• The wind carries the dangerous particles in the air to other places. Thus, causing dimming in other places.

EFFECTS OF GLOBAL DIMMING

Global dimming affects the planet in many different ways. All living things on Earth get their energy from the sun. If there was no sun, the earth would become a big ball of ice floating in space. (Research from The Guardian)

Impacts the Hydrological Cycle

• The hydrological cycle is very important for the survival of the planet. It makes sure that all organisms in an ecosystem get enough water.
• One of the things that happen in the hydrological cycle is evapotranspiration. It can only happen when the sun heats water to a certain level.
• Global dimming will block the sun’s energy. Then that will slow down the rate at which water evaporates from the ground. This will mess with the hydrological cycle, which will change the climate.
• Changes in the hydrological cycle can have an effect on both land and sea animals.

Decrease in Global Temperatures

• Aerosols in the air protect the earth’s surface from the sun. This lowers the temperature all over the world.
• Areas that have a lot of solar dimming may have cold weather. This is due to the fact that the heat is blocked and reflected into space.
• There is some good news about global dimming.  The drop in temperature can help to counteract the effects of global warming.

Drought

• Drought can happen when an area doesn’t get enough rain for a long time. Many water droplets make clouds. Rain comes from clouds.
• Solar energy is needed for the clouds to start to form. The sun’s heat warms up water in large bodies of water, which makes it evaporate.
• When particulates in the air block the sun’s heat, rain clouds are less likely to form.Then this leads to drought.
• Many people have died because of global dimming. It has also changed ecological patterns in different parts of the world. In fact some places are less able to grow food.
•  The Sahelian droughts may happen in part due to the darkening of the world’s skies.

HOW TO REDUCE GLOBAL DIMMING

Reducing pollution is the best way to cut down on global dimming:

• Using fossil fuels is bad for the environment. They put greenhouse gasses and aerosols into the air, which can damage the climate.
• Gas-powered vehicles should be replaced with electric vehicles to minimize the emission of particulates.
• It is better for the environment if people use renewable energy sources. Solar panels and windmills can make electricity without causing as much air pollution.

WHAT IS THE DIFFERENCE BETWEEN GLOBAL WARMING AND GLOBAL DIMMING?

Both global warming and global dimming have bad effects on the world. However, these two processes are not the same:

• Global dimming cools things down, while global warming raises the temperature.
• It is because of global dimming that there is less evaporation, which causes drought. Global warming, on the other hand, can lead to more rain because it speeds up the process of evapotranspiration.
• Global warming is caused by the greenhouse effect, and global dimming is caused by the buildup of aerosols.

GLOBAL DIMMING AND CLIMATE CHANGE

Earth may not be as bright as it used to be because of global dimming. Particulates in the air not only change the climate, but they also mess with ecological systems. Global dimming has caused long-term drought in some regions, resulting in the loss of lives and animal habitats. It can also lead to a slow drop in global temperatures, which can harm the environment.

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