I happen to see a very interesting special program in BBC today, which has driven me to write the third blog post of this day.
For years, right from our school days, we have been very familiar with the term ‘Global Warming’. But today, I got to become acquainted with a new terminology known as ‘Global Dimming’. We knew global warming occurs as a result of extensive addition of particulate matter, mainly due to the burning of fossil fuels all over the world. Though the developed nations put the blame on developing nations like India, for increasing the global warming further up the record. It has now been proved that for most of the natural calamities which happened in the last two decades are mainly due to the activities of the developed nations.
Explaining this further, right from the start of the industrialization we (mainly today’s’ industrialized nations) have dumped a massive amount of green house gases into our earth’s atmosphere. This has been causing an very interesting as well as unexpected happening which has never struck the brilliant brains’ of our scientists all over this brilliant planet. Now, it has developed into a very significant factor called global dimming.
As the term indicates, it has been causing a dimming effect all over the earth’s atmosphere, prevalent especially in the upper regions of atmosphere well above the cloud region. The greenhouse gases with a high level of particulate content got deposited in higher levels of atmosphere, where the cloud formation occurs. A further look into the gimmicks of what happens during the cloud formation and rainfall will help in understanding the dimming effect in the following paragraph. In the higher regions of atmosphere, the water droplets condense around the minute particulates. More and more water molecules condense over the same particulate, that the overall weight of the droplet increases. This especially happens in warmer regions of the sky and when the droplets weight goes above the threshold they fall down as rain.
Now taking the conditions which had been happening since 1950s due to massive industrialization and dumping of huge volumes of greenhouse gases into the atmosphere, the average size of the particulate matter started increasing. As the weight of the particulates increase, the threshold value for the water droplet to cause rain also increases. Thus, the condition which lead to the rains became sparse. This resulted in reduced rainfall in equatorial and sub-equatorial regions of the earth and thereby leading to famines. The famine of Somalia actually alarmed the global environmentalists and scientists who later found this amazing reason.
Coming back to global dimming, when the high-particulate gases reach the atmosphere and participate in cloud formation, a different variant of normal clouds form – Clouds which have the propoerty of reflecting the solar radiation back into outer space rather than inside the earth. Though scientists initially considered this to be influential to tackle global warming, later discovered this to be as bad as greenhouse global warming. The peculiar phenomenon is, this dimming was actually causing the failure of rains in the above said equatorial and surrounding regions. For monsoon rains and summer rains to occur in Africa and South-Asia respectively, they need hotter conditions to exists. such a condition causes the movement of rain clouds from the southern hemisphere to the equatorial regions. When these clouds occur at warmer equatorial regions, they fall as rain.
But the dimming prevents such a hotter region to be developed and thereby there is no condition existing in these regions for rain to pour down. This has led to the sufferings due to poor rains and failure of monsoons for the past two decades.
The entire 2 hour featured programs was really an eye openers. The first part featured how the concept of global dimming got into existence, whole the later part was aimed at exploring a formidable solution to this problem. Hope, the entire world starts exploring ways to prevent from this wonderful planet moving towards a place not very much suitable for human existence.