Black Carbon & climate change Part 2 (Rainfall)

This blog explores impact Black Carbon is having on rainfall in South Asia.

Atmospheric brown clouds (ABC)
   
It is made up of layers of pollution which contain aerosols like black carbon, organic carbon and dust particles which will then cause absorption and solar radiation to be displaced.

 Below is a great short video clip from CNN.

In South Asia black carbon and fossil fuel emissions levels have increased six times since the 1930s, which has been fuelling the growth of these Atmospheric brown clouds. It has led to

1) Surface solar radiation to decrease by 10 % which in turn reduces surface evaporation from land and sea
2) Dimming - 8 % decrease from 1930 to 2000 -which in turn leads to a reduction in surface evaporation from Indian
4) Atmospheric solar heating - doubled since 1930
5) Summer monsoon rainfall weakened - decline in summer rainfall by 5 %


There is a concern about the decline on monsoon rainfall in India as the link between rainfall and food production is strong. In this paper by Auffhammer et al (2006) he believes this has led to a reduction in the harvest of rice in India. The estimated impact from Atmospheric brown clouds on rise harvest between 1966 - 84 was 3.94 % by the period of 1985 and 1998 this increased to 10.6 %

While there is evidence that ABC might be causing this decline in rainfall - there could be other reasons such as the El Nino - southern oscillation below is a short clip about how it affects India.