Global warming and global dimming are two big issues that have drawn attention in the recent years. Due to industrial revolution, increase in population, and growing demands of the people, these issues are booming out. They pose great danger to our earth and the sole responsibility is in our hands. First, it is necessary to know about these two phenomenon and how it affects us. Let's start.
What is Global Dimming?
It is a phenomenon that happens due to reduction in the solar rays falling on the earth's surface. The residues and particulates such as sulfur dioxide, ash, soot (black carbon), that are produced after combustion of fossil fuels cause global dimming. These pollutants evaporate and add to the droplets in the cloud. The clouds that contain the sulfate aerosols (cloud of solid or liquid particles in a gas), have a high reflective property, due to which they reflect the suns rays that fall on them, back to the space. Solar rays are very essential for the balance in water cycle.
When the solar rays are reflected back to the space by these particulates, then what happens? It causes reduction in water vapor content in the atmosphere, which eventually results in less rainfall. The study about this topic was first started by Gerry Stanhill, an English scientist who studied about solar radiations in Israel. Gerry Stanhill compared the amount of solar radiation from 1950s with the recent solar radiation records. He stated that "There was a staggering 22% drop in the sunlight, and that really amazed me".
Impacts of Global Dimming
We all know how significant is rainfall for our living. The clear-cut effect of global dimming is 'famine' and 'drought'. It was found that, the famines that happened during 1970s and 1980s were a direct effect of rainfall shortage which is a cause of this phenomenon. Billions of people from all over the world including America, Europe, Asia, Africa are affected due to it, in the form of famines. Several areas in North Africa got dried out due to inadequate rainfall. Even though Africa did not contribute much to it by burning of fossil fuels, industrialization etc., it was badly affected than any other developed and developing countries.
The developed countries such as the US is affected by acid rain, which is caused by the aerosols in the clouds. The process of photosynthesis in the plants can reduce due to shortage of solar rays. The sulfur aerosols when inhaled, can cause respiratory diseases in human beings.
Interesting Evidence of Global Dimming
Three days after 9/11 attacks, scientists found that the sky was abnormally so clear. They found that the reason behind this kind of climatic change is due to grounding hundreds of fleets at the same time. The contrails (artificial vapor cloud created by the air crafts) from the jets and air crafts that landed in the US after the attack, were the causes for such a climatic change. It was later revealed by Travis, D.J., Carleton, a scientist who studied this phenomenon, that the temperature during the three days after 9/11, was reduced to 1 degree from the average range before 9/11 and few days after the incident.
The 1 degree Celsius reduction in temperature is nothing much for a common man, but scientific records reveal that this kind of abrupt reduction in temperature can have adverse effects in future.
What is Global Warming?
It is a phenomenon caused by increase in the atmospheric temperature of the earth's surface, due to increase in concentration of greenhouse gases such as carbon dioxide, methane, nitrous oxide, chlorofluorocarbons (CFC), etc. These greenhouse gases trap the solar rays and cause temperature rise in the earth's atmosphere. This process of trapping solar energy is called greenhouse effect. Increase in population causes demand in energy sources by burning of fossil fuels and cutting down trees (deforestation) which is major cause for global warming.
It is clear that, burning of fossil fuels directly contributes to global warming by releasing greenhouse gases, but how does deforestation contribute to it? Trees and plants take in carbon dioxide and give out oxygen. If these plants and trees are cut down, the carbon dioxide will remain unused in the atmosphere, and increase the temperature of the earth's surface, which is called global warming!
Impacts of Global Warming
In recent years, we have heard a lot about floods, hurricanes, tornadoes, droughts, extinction of certain species, earthquakes, etc. What do you think about all these? Humans are interfering too much with the nature and act against it in many ways. The natural balance in the earth is being shaken by our activities and the direct result is global warming. Glaciers in the polar regions and mountains melt down and the sea level rises which is all due to increase in temperature, and it causes floods, and damage to the food crops.
Large areas of lands are damaged permanently due to extraction of fossil fuels from deep underground. This leads to frequent earthquakes. Ozone layer is a blanket that entirely covers the earth's surface and protects it from harmful UV (ultraviolet) radiations. The CFC that is emitted from refrigerators and insecticides, depletes the ozone layer and makes our earth vulnerable to harmful UV rays.
- The basic difference between the two phenomenon is that, global warming causes heating effect in the earth's atmosphere, whereas global dimming causes cooling effect.
- Global warming is caused by greenhouse gases and global dimming is caused by aerosols.
- Global warming traps sunlight and global dimming blocks sunlight.
The common thing between global warming and global dimming is that, they both are destructive to our earth. They both cause environmental and ecological problems to earth. Government and people in developed and developing countries should be more cautious and take the necessary steps to mitigate the effects of global warming and global dimming, because in most cases, countries like Africa which is not a developed country is always the most affected and falls prey to these phenomenon, due to industrialization and other acts of the people in the developed countries like the US. To avoid such a disparity, we all should join hands irrespective of the countries we belong to, and protect our earth from the adverse effects of global warming and global dimming.