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Updated: Sep 20, 2019 11:26 IST

India will conduct a national review in the coming months, modelled on the assessment done by the Intergovernmental Panel on Climate Change (IPCC), to determine the impact of a warming climate on the subcontinent.

The national assessment, commissioned by the ministry of earth sciences (MoES), will be published every five to six years.

The assessment will tell “us what we know but in much more detail like events of heavy precipitation and heatwaves will increase, so will dry spells, and intensity of tropical cyclones will go up. But the assessment will not tell us how various sectors like agriculture, health and economy will be impacted,” said M Rajeevan, secretary, MoES.

The document may be available only after the 25th conference of parties to the UN Framework Convention on Climate Change (UNFCCC) in Chile in December 2019. It is expected to be available in 2020 when the Paris Agreement is operationalised.

The finance ministry, in a note on climate change earlier this week, mentioned that India was juxtaposed between the Himalayas and the India Ocean and that the subcontinent was subject to higher climate variability compared to the continental climates of North America and Europe.

The annual mean, maximum and minimum temperatures during the period 1901 to 2010 show a significant increasing trend of 0.6°C, 1°C and 0.18°C, respectively, it said. Daily rainfall observations during 1901-2004 indicated that the frequency of extreme rainfall events (rain rate > 100 mm/day) rose significantly. Several IMD studies have highlighted the climate change hotspots in India — central India, for example, is the most vulnerable to extreme rain events. One of the findings of the assessment is that intensity of Category 4 and 5 cyclones will increase. Cyclones are ranked on a five-scale intensity index based on severity from Category 5 being the strongest.

Several countries are now considering domestic climate change assessments to be better prepared, according to R Krishnan,an Indian Institute of Tropical Meteorology (IITM) scientist who is curating the assessment. “It will be a useful document for policymakers. IPCC makes global projections. There are knowledge gaps for individual countries, so ministry is keen that we know what to expect in India,” he said.

Scientists and scientific institutions have been forthcoming in recording impact and assessing what a 2°C warming scenario means for India. A study by the IITM earlier this year warned that the frequency and duration of heat waves in April, May and June will increase dramatically during the 2020-2064 period.

Worse, even southern and coastal parts of the country, which are presently unaffected by heat waves, are likely to be affected by heat waves. Both heat wave frequency and duration will increase significantly in the core heat wave zone over central and northwest India by 0.5 events per decade and 4-7 days per decade respectively.

The Divecha Institute of Climate Change at the Indian Institute of Science-Bangalore (IISc-B), for example, has prepared several research notes on how climate change is impacting the Himalayas. For the past three decades, the mean temperature increase in the Himalayas has been higher than the global mean. It has projected that the Himalayan region will experience a temperature rise of approximately 2.4°C in a low emission scenario and as high as 5.5°C in a high emission scenario by end of 21st century, which would mean an increase in disasters like glacial lake outburst floods and implications for water availability.

(HT is participating in Covering Climate Now, a global journalism initiative committed to bringing more and better coverage to the defining story of our time)