New Delhi: As heavy rain, record heat waves and severe cold waves intensified across the country in 2019, the year served as another reminder of how India is one of the countries that are the most vulnerable to the impact of climate change.
“There is no denying that the rise of these extreme weather events in India is linked to the global patterns of climate change. Be it severe heat waves during summer, cold waves during winter, or intense heavy rain during monsoon, everything has an imprint of climate change," said M. Mohapatra, director general of meteorology, India Meteorological Department (IMD), New Delhi.
The World Meteorological Organization (WMO) says the decade starting 2011 remains on track to be the warmest on record. It is this consistent warming, especially prominent since the 1970s, which has altered major weather patterns across countries.
In India, the annual mean surface temperatures in 2019 remained far above normal in all the four seasons. The annual mean land surface air temperature for the country was +0.36°C above the 1981-2010 period average, making the year the seventh warmest year on record since 1901, according to IMD.
Higher daily peak temperatures have become increasingly frequent and the number of days with heat waves has also gone up, according to scientists.
In 2019, as many as 350 people died in one of the longest heatwaves in May-June, which is one of the deadliest weather hazard globally, according to WMO.
The monsoon season in 2019, from June to September, was also the warmest in a century. Floods triggered by heavy rain claimed over 850 lives across states.
“The moisture holding capacity of the atmosphere is increasing, and there is enhanced uplifting of warm, moist air from the sea. This is leading to formation of more deep convective clouds and so increase in thunderstorms and lightning," said Mohapatra.
Warmer air holds more moisture and studies show that the relative humidity in the troposphere has increased by 2% over the sub-continent in last three decades.
Increased warming is also raising the potential of oceans to form intense cyclonic disturbances.
The year saw as many as eight tropical cyclones in North Indian Ocean. While the Bay of Bengal was relatively subdued with only three cyclones, Arabian Sea saw its most intense cyclone season ever with as many as five cyclones, compared to the usual occurrence of one every year.
“The intensity of cyclones developing in Arabian Sea is on rise. But apart from higher sea-surface temperatures, active north-east monsoon conditions and a weather system called Madden Jullian Oscillation (MJO) also favoured cyclone formation last year," said Mohapatra.
Warming is also impacting systems like MJO, which are linked to formation of tropical cyclones.
A recent study led by the Indian Institute of Tropical Meteorology (IITM), Pune showed how rapid warming of the Indo-Pacific warm pool has altered MJO, which could impact formation of cyclones in the north Indian Ocean in the post monsoon season.
Roxy Mathew Koll, from IITM, Pune, who led the study, says the impacts of climate change have unfolded sooner than expected, and India is beginning to witness the consequences.
“The world is hotter than ever before and as per WMO average temperature are set to rise to at least 1.2-1.3°C above pre-industrial levels over the next five years. This means, that the extreme events which we have been witnessing now are only going to rise. We can contain the damage if we step up our action now and put into place early warning systems across the country," said Koll.