Is Global Dimming Reducing Global Warming?

Posted on November 10, 2010 in Environment

By Harsimrat Parmar:

Ever wondered, what if the Sun dies? What if it refuses to shine? No photosynthesis forever! The Sun’s gravity holds us in orbit, so if it was gone, we’d go flying off into space. Also, there’d be no light and no food chain.

Sun is the most vital part of our ecosystem. Life is impossible with no sun. Scientists have discovered that the sun light is reducing every decade gradually. And it is a worrisome situation. As per observations, the evaporation is loosing its strength over Russia, Eastern Europe and US. Measurements say that evaporation reduced by about 100mm less over 30 years. The report of drop in evaporation was exactly the same as drop in sunlight after the research. During the research, Pan Evaporation technique was used in which as the global climate warms, all other things being equal, evaporation will increase and as a result the hydrological cycle will accelerate. The sunlight is becoming lighter.

This phenomenon of reduction in sun light that reaches the Earth is called Global Dimming. Global Dimming is the gradual reduction in the amount of global direct radiance at the earth’s surface that was observed for several decades after the start of systematic measurements in the 1950s. The effect varies by location but has shown its impact across the world.

It took scientists little more than ten years to find out the cause of this phenomenon. Many experiments were conducted. A climate scientist named Veerabhadran Ramanathan from University of California along with his team conducted various experiments during the 90’s in the Maldives and reached to the conclusion that yet again it is the pollution which is the cause. Almost anything we do to produce energy causes pollution. The pollution caused by the ignition of fossil fuels leads to reduction in the sun light reaching the surface of the earth. The thick layer of the particle pollution cuts down the solar supply by more than 10%. Particles such as sulphates, nitrates, ash and soot created by various human-activities cause the particle pollution.

There are effects of every phenomenon so does Global Dimming! The massive famines caused during 1960-70s in Africa are the effects of dimming. Millions of people died and around 50 million were affected. These famines can be accounted as the aftermaths of the disturbed rainfall trends of the world. The scientists have proved that due to the particles which are created by burning of fuels are suspended in the air there is an impact on the clouds. A cloud is a visible mass of droplets of water or frozen crystals suspended in the atmosphere above the surface of the Earth or other planetary body. These droplets combine together to form a larger droplet which when becomes heavy becomes a rain drop. The particles in the atmosphere provide sites around which water droplets can be formed. This results into many small water droplets, which act as mirrors, and do not cause rain as well affecting the rainfall trend. And the mirrors formed cause the reflection of around 10% of the sunlight.

September 11, 2001 has played a major role in the research of global dimming. After the terrorist attack, all the flights to and from US were sealed. Hence forth there was no air traffic for three days. It helped a scientist to observe the temperatures of the entire US through the weather stations situated in all the states. The results were astonishing. There was a tremendous increase in the temperature range i.e. the highest and the lowest temperature recorded during a day. Thus it was clear that the dimming is due to the particle pollution. But the other aspect of worry that arose was if only one source of pollution can affect the temperature so much what if there is a decrease in pollution?

So now the crux of the problem is, is global dimming good? Is it protecting us from the devastating affects of global warming? What if we are able to fight global dimming?

In present circumstances, we need to consider the combined effects of global warming & global dimming.

The world must come together and reduce the aggregate demand for oil. It is essential that we work towards developing alternative sources of energy such as solar energy, hydro-electricity, and wind-energy. What ever we do we need to hurry because we are running short of time.

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