How El Nino impacts monsoon rainfall in India

The India Meteorological Department (IMD) has forecast a 60 per cent probability of El Nino this year along with a below-normal monsoon projection. A strong El Nino can cause drought-like conditions.

El Nino is a weather condition that lasts for about a year on average. This period coincides with the warming of sea surface temperatures that affect wind patterns and trigger floods and droughts in different parts of the world.

According to Skymet, a private weather forecaster, El Nino and Indian monsoon are inversely related. The most prominent droughts in India - six of them - since 1871 have been El Nino droughts, including the recent ones in 2002 and 2009, it said.

However, not all El Nino years led to a drought in India. For instance, 1997/98 was a strong El Nino year but there was no drought. On the other hand, a moderate El Nino in 2002 resulted in one of the worst droughts.

Historical data for 126 years (1880-2005) compiled by Skymet show that about 90 per cent of all evolving El Nino years have led to below-normal rainfall and 65 per cent of evolving El Nino years have resulted in droughts. However, one thing is clear that El Nino years do affect monsoon rainfall in India. During this time, the rainfall is generally below normal, which has its bearing on crop production.

A phenomenon opposite to El Nino is La Nina. During this, less heating leads to colder sea waters off the western South America Coast, thus making it a high-pressure zone. This pushes moist sea winds towards the Indian Ocean and increases the chance of normal or excessive rainfall in India.

El Nino directly impacts India's agrarian economy as it tends to lower the production of summer crops such as rice, sugarcane, cotton and oilseeds. The ultimate impact is seen in the form of high inflation and low gross domestic product growth as agriculture contributes around 14 per cent to the Indian economy.