Urgency, Implications and India: A Conversation with J. Srinivasan on Climate Change
J. Srinivasan, a distinguished scientist at the Divecha Centre for Climate Change and honorary professor, the Centre for Atmospheric and Ocean Sciences, Indian Institute of Science, Bangalore is an eminent climate researcher.
As an expert who advises on the planning and implementation of climate-related projects and programs, he attracts many to climate action and research. Known popularly as J.S., Srinivasan is an icon and an inspiration to climate researchers worldwide.
JS started the conversation by recounting how he got involved in climate science research in 1982 when Professor Roddam Narasimha established the Centre for Atmospheric Studies (CAOS) at the Indian Institute of Science. His expertise in heat transfer, gained from his higher studies at Stanford University, which was fundamental to the understanding of atmospheric processes facilitated his transformation as a climate scientist.
Rising global temperature
On the question about global warming and its effects, JS quoted NOAA’s report saying that 2023 was the planet’s warmest year on record when earth’s average land and ocean surface temperature was 1.18°C, the highest global temperature in NOAA’s 1850-2023 year climate record. This exceeded the pre-industrial (1850–1900) average by 1.35°C.
The dangerous part is that 90% of global warming takes place in the ocean, leading to an increase in the internal heat and expansion of water, resulting in sea level rise. The increase is not just surficial, but affects the upper two kilometres. This change is crucial as the ocean dictates our weather patterns by transferring heat and moisture into the atmosphere. Higher sea temperatures may also cause more severe storms in tropical parts of the world, posing a threat to life and infrastructure.
The sea is home to most of our biodiversity, with three billion people globally relying on it for their livelihoods.
On the health issue, JS recalled the World Health Organisation’s estimate that climate change will cause around a quarter of a million additional deaths each year by 2030-50, from malnutrition, malaria, diarrhoea and heat stress. Rising temperatures also contribute to worsening air quality, which can increase the risk and severity of asthma attacks. A big threat is from sea level rises, which could affect the global supply chains, and put ports and coastal infrastructure out of action. According to the UN, carbon emissions from human activity are causing ocean warming, acidification and oxygen loss, putting large numbers of marine-related jobs at risk.
Impact of heat waves
On the issue of heat waves and how it affects people, JS cited the World Meteorological Organization’s, definition of heatwave as "more than 5 consecutive days where the daily maximum temperature exceeds the average maximum temperature by 5°C or more”.
The effects of heat waves are global, from Europe to Russia to India, and he recalled how more than 70,000 people died during a record-breaking heat wave that left Europe sweltering in June, July and August 2003. Look at Moscow, which never anticipated any impact from global warming and enjoyed an average maximum July temperature of about 23°C until 2000.
However, during the summer of 2010, the temperature crossed 40°C, with some cities touching 44°C, and in the drought conditions that followed, around 9 million hectares of crops perished. Such temperatures, coupled with the pollution from the fire and smog, took its toll and Moscow recorded over 14,000 deaths.
Photo: Nomad Tales/Flickr. CC BY-SA 2.0.
India is also affected by heatwave conditions every year, usually in the dry season, from March to May. During the summer of 2024, Churu in Rajasthan recorded 50.5°C which was the highest temperature in India in eight years. In the 2024 heatwave, more than 200 people died in India and 25,000 people suffered from heat stroke. The causalities were mostly among outdoor labourers.
Advancement of climate science
About the significant advances in climate change research, the major developments are in data gathering and fast computing facilities leading to more reliable climate models. From regional grids of 50x50 km and local grids of 20x20 km, the future models are moving to 1x1 km grids.
A great advancement is in the use of satellites that have an unparalleled capability for measuring sea-surface temperature from space, and land surface temperature from space. Sentinel 3, an earth observation heavy satellite series developed by the European Space Agency is the latest development in this area.
China, India and the US are among the top countries with the most climate satellites in operation, which provide un unprecedented global view. More than 16 “climate satellites” operated by these nations are continuously collecting data also from regions that are not easily accessible.
What do climate models say?
On the issue of predicting the monsoon, JS mentioned that although several climate models (50-60) are available for predictions, they give different results making them unreliable. Monsoon rainfall predictions for three days, are very good and medium-range predictions (seven days) are getting better.
However, predictions for longer periods are tougher, but they might get better in future, especially with the support of AI.
Most climate models predict an increase in Indian summer monsoon rainfall, but the pattern could be random. Measurable melting of Himalayan glaciers which could lead to breaching of rivers and rise in sea level could impact both coasts of India. Predictions about the place, amount and duration of rainfall are difficult but these issues can be dealt with through proper urban infrastructure. For developing countries including India, where frequent spells of increased rainfall are expected, there needs to be more focus on irrigation.
A vendor sells fruits amid heavy rainfall, in Kanyakumari district, Tamil Nadu, Tuesday, March 11, 2025. Photo: PTI.
Over the decades, there have been many changes in the landscape and there is a need to develop new models incorporating these changes as well as the vegetative cover. Heavy rainfall over a short duration often results in urban floods, and this issue needs to be addressed by creating proper infrastructure and effective water management strategies.
What do global models say?
The global climate models predict that earth's global average temperature will rise an additional 4°C during the 21st century if greenhouse gas levels continue to rise at the present levels. Globally, the atmosphere is expected to become richer in moisture in response to global warming. Dry summer heatwaves severely impact agriculture, ecosystems, water supplies, and local economies. The combination of high temperature and humidity can be more repressive for people, especially in the coastal areas, and there is the additional threat from coastal flooding. JS cautions how climate change could be a threat multiplier as multiple levels of human activities would compound the impact. Excessive pumping of groundwater causes subsidence of land, which would magnify the effect of inundation from coastal flooding. Unplanned development of coastal areas, like unscientific land reclamation and destruction of coastal swamps would only add to the impact.
The increasing incidences of landslides and cloud bursts in the Himalayas and elsewhere also show how climate change can be a “threat multiplier”.
Take the case of the Wayanad landslide on July 30 that claimed 375 lives, and displaced 10,000 people, a trigger that followed was the unprecedented, relentless rainfall of 409 millimetres within 24 hours in July 2024. Unplanned land use and highly altered natural hydrological conditions added to the impact, making the event a ‘threat multiplier’.
In the Western Ghats, timely implementation of recommendations, such as the Gadgil committee report, and careful land use practices would have reduced the magnitude of the disaster. Climate scientists need to reach out to the concerned units of administration, politicians and the general public, to create awareness about climate change. It is important to learn from experiences, within our surroundings and elsewhere. They also need to educate the local population, who are the ultimate victims, about the inevitable aspects of climate change that would get worse if there is no preparedness.
Winners and losers and lessons from the past
Global warming is said to result in winners and losers, and history testifies to that predicament. The world had mostly been warming for thousands of years before the industrial era began, and that warming has indisputably favoured the spread of civilisation. Today, the world’s economic geography is organised according to a stabilised climate since the Middle Ages. Europe’s Medieval Warm Period, from around 1000 to 1400 CE, which saw the rise of Spain, France, and England, allowed the expansion of farm production, population, cities, and universities, setting the stage for the Industrial Revolution. Here are the clear winners.
And there are losers. The 1800 BC Maya settlements that spread across today's Guatemala, Mexico, Belize, Honduras, and El Salvador, experienced a demographic disaster, the greatest in human history between about AD 750 and 950. Due to a shortage in rainfall, many of the densely populated urban centres were permanently abandoned and the classic Maya civilisation ended.
Cultures in various Asian countries have also suffered from climatic fluctuations. According Monsoon Asian Drought Atlas, the 16th and 17th centuries experienced some of the most highly variable periods dry and wet periods and the Ming Dynasty of China ended during the drought of 1638. The drought of during 1769 to 1773 and the East Indian Drought of 1790 to 1796, each resulted in millions of deaths due to starvation. Thus, the 18th century is one of the most tumultuous periods of the past millennium, when successive decades of weakened monsoons took their toll.
Where does India stand, in terms of water availability? JS feels India stands to lose, due to the rising demand from the increasing population, and with no projected increase in rainfall. The decline in groundwater, which many parts of India are already facing, would add to the farmer's distress and reduce agricultural yield.
Farmers take part in a drive to desilt the Indravati river, at Jora Nala in Bastar district, Wednesday, March 12, 2025. Photo: PTI
Climate changes denialists
While people around the world are becoming more concerned about climate change, climate change denialism persists in one form or another. JS noted how cynicism prevails in the media, government, political and economic establishments, the general public, and even among a section of scientists. Although many are critical of climate change and believe that it is an exaggerated issue, an overwhelming consensus of 97% of climate scientists believe that global warming caused by anthropogenic activity has reached unprecedented levels in human history so it has become an emergency that threatens the entire planet.
We tend to be insensitive to data from around the world in favour of what we experience in our own lives. Personally experiencing record-breaking heatwaves and flooding tends to increase belief in climate change. It is also true that public opinion is often by political leaders, media and other influencers, which include industrial houses that do not like the idea of climate change because it would affect their businesses.
The only way to address this issue is through education. People need to understand what is happening around the world. They need to realise that what is happening to someone else somewhere can happen to them, someday. They need to understand that the earth could change and it will not always be for the betterment of humanity. As one who has been a part of IPCC, he realises its limitations as an advisory body, with no authority for implementation. It is for the participating nations to develop a consensus, gather more data, make strong recommendations, communicate with the public and move on. It is a fact that unless something catastrophic happens, people do not react or comply. The sense of urgency needs to be communicated to the public and the administration should prepare their action plans, ahead of any impending disaster.
The interview was first published in the Malayalam weekly, Mathrubhoomi, February 23-March 1, 2025. Excerpts have been translated by Kusala Rajendran.
C.P. Rajendran is a geoscientist and a communicator on science policies, environment and education.
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