In the last few years, particularly in the last 3 -4 years, we get the news that several parts of the world had the hottest day in 50 years, 70 years or even in recorded history. This has led people to conclude that there is global warming and that the ice at the poles would melt, leading to the submerging of several island countries. The conclusion is incorrect.
During this same time period, we also read news that several parts of the world experienced the coldest day in several decades or even the coldest day in recorded history. This means that what we witness now is not global warming but rather weather extremes. While estimating the increase in the volume of sea water and rise in sea level, the following need to be kept in mind.
- When it is hot in the northern hemisphere, it is cold in the southern hemisphere. Thus the snow melting is restricted to just 50% of the area of snow
- When snow melts, the volume of the melted snow, i.e water comes down by around 10%.
- During summer, when snow melts and raises sea water level, there is substantial evaporation of sea water leading to lowering of sea water level. Evaporation has been calculated to be higher than the quantum of flow of river water into the sea.
- With increased use of surface water, the flow of water into the sea from the rivers is decreasing steadily.
- With increasing exploitation of ground water, seepage of seawater into the earth takes place, reducing sea water level.
Based on these points, the consequences of ”global warming” is not so alarming as is made out by some scientists or experts.
However, it has to be noted that the rivers bring into the sea not only water, but also mud, sand, salt and minerals which, get deposited into the sea, thus reducing the quantum of water which the sea can hold. Dredging to the extent possible, extraction of minerals, desalination of sea water for irrigation purposes as well as for other uses including industrial use would all serve to reduce sea water level.