1.5 degrees of aberration | Is India prepared to deal with the fallout of increasing emissions and long-term warming in the near future?

India faces severe climate impacts, including heatwaves, cyclones, and water-related disasters, requiring urgent adaptation and policy action.

On January 20, 2025, Donald Trump withdrew the United States, the largest historical greenhouse gas emitter and second-largest annual emitter currently, from the Paris Agreement for the second time and promised record fossil fuel expansion. With that, the 1.5 degrees Celsius goal that was already on life support earlier is now decidedly out of reach. It may even arrive earlier than expected if global emissions soar due to Trump’s climate policy backtracking and its knock-on effects, counteracting the emission reductions from the rest of the world and other large emitters such as China.

For a vast country like India, the challenges from climate impacts are not only numerous but can also be drastic, severely impacting development goals. 2024 being the first time any single year has crossed 1.5 degrees Celsius of warming and the hottest ever, probably in the whole of human history — about 1.6 degrees Celsius warmer than pre-industrial levels — is a grim and symbolic marker of the world’s failure to limit warming.

This portents turbulent times ahead for India in dealing with the fallout of increasing emissions and breaching 1.5 degrees of long-term warming in the near future (2030s). But what exactly does it mean for a highly populated and climate vulnerable, developing country with diverse geographies, a growing economy and great inequalities? We ask leading climate scientists to weigh in on what India at 1.5 degrees Celsius would look like and how to prepare for changes that were expected by 2100 but are now imminent in the coming decade.

Last year’s heatwave sent shockwaves around the globe when Delhi, one of the world’s most populated capitals with a large section of people in highly vulnerable conditions, recorded temperatures as high as 52.3 degrees Celsius, prompting both fear and scepticism if perhaps a faulty sensor was responsible for the confusion. However, 50-degree days are already becoming more frequent around large parts of the country as the global temperature rises.

Krishna AchutaRao, Dean and Professor at the Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, says, “The effect of even a small change in the tropics is significant because we are already at the edge of what is possible to live with — be it extreme temperatures or rainfall. The full extent of the impacts we face — either from the slow-moving changes in the mean or the increased extreme events — is not yet fully accounted for.”

In order to help climate science inform adaptation policy, his group at IIT Delhi analysed future heatwaves over India in both 1.5 degrees Celsius and 2 degrees Celsius warmer worlds. In a recent study, they found higher extremes in temperatures are unlikely, but the increasing coverage is more worrisome. “The likelihood of large parts of the country experiencing two-month-long heatwaves is alarmingly high and we are not prepared for such events. The chance of heatwaves into July are also projected to increase, which is an alarming prospect considering that the monsoon would have set in already by then and the humidity will be high,” says AchutaRao.

Previous studies have found that high humidity can create dangerous conditions even in seemingly lower temperatures due to the inability of the human body to thermoregulate and cool itself down through sweating. Another study found that 3.7 billion people in the tropical belt, which includes peninsular India, will be at high risk of high humidity-induced heat stress nearing the human physiological limits if temperature crosses 1.5 degrees Celsius. Humidity is the reason why the dry heat of Delhi or Hyderabad seems much more bearable than the humid summers of Mumbai or Chennai.