The climate emergency is real for India

With a rise in earth's temperature inevitable now, India needs to empower and make every district climate-change ready in order to mitigate its impact on the poorest populations

The climate has changed forever and will remain so for centuries, if not a few thousand years into the future. Human-caused carbon dioxide emissions are responsible for it, and our current mitigation strategies are insufficient to stop it from changing further. The global mean temperature will cross the 1.5°C limit in the current decade or next, and the 2°C mark during 2040–2060. This is the sixth assessment report of the Intergovernmental Panel on Climate Change (IPCC) in a nutshell.

Let us first look at some of the irreversible climate change and extreme weather events that have already set in and are going to intensify further. 

Some of the most significant changes occurred in the ocean, but with obvious implications for the climate over the land. This is because the oceans absorb more than 93 per cent of the heat from global warming. In turn, the global ocean has warmed and acidified, and oxygen levels have dropped since the 1970s. Over the rest of the 21st century, ocean warming might increase four to eight times the current change under high emission scenarios. Ocean acidification, deoxygenation, and stratification will continue to increase in the 21st century. These changes in the ocean are irreversible and will last for centuries if not a millennium or more.

The Arctic Ocean will likely become practically ice-free during northern summers for the first time before 2050, even if we cut down our emissions drastically. There is already a 40 per cent decline in Arctic Sea ice area during peak summer since the 1970s, which will continue into the future. The Greenland ice sheet has also lost mass since the 1990s and will continue to lose mass, contributing to sea level rise. Under continued warming, glaciers will be lost globally and regions with small glaciers, such as the European Alps and low latitude mountains, will lose most or all glaciers by 2100. Mountain and polar glaciers will continue melting for decades or centuries.

Due to ice-glacier melting and thermal expansion of water, sea level is increasing faster than ever. The average rate of global sea level rise was 1.3 cm per decade between 1901 and 1971, increasing to 1.9 cm per decade between 1971 and 2006, and further increasing to 3.7 cm per decade between 2006 and 2018. For the Indian subcontinent, the current rate is between 3 and 5 cm per decade from the west to the east coast, with the land subsidence along the Bangladesh coast aggravating the impact. A 3 cm per decade of sea level rise is equivalent to a disproportionate 17 metres of land carved away from the coast every decade, considering the slope along the coastal zone.

Under moderate-to-high emission scenarios, the sea level will rise further, between 40 cm to 1 metre by 2100. The IPCC report says that the sea level rise approaching 2 metres by 2100 cannot be ruled out due to deep uncertainty in ice-sheet processes. The sea level rise will also continue for centuries to millennia due to continuing deep ocean warming and ice sheet melt.

Illustration: Binay Sinha

Since the 1950s, the tropical ocean has been warming faster than other regions, with the tropical Indian Ocean warming even faster than the rest of the tropical ocean basins. This has already put immense pressure on the Indian subcontinent, particularly the coastal regions. Water expands and increases in volume with the heat, contributing to the sea level rise along the Indian coast. The monsoon and the cyclones source their moisture and energy from the warm waters of the Indian Ocean, and they have intensified. With the rapid ocean warming, we see a threefold rise in extreme rains causing floods across India—while the total monsoon rainfall has declined in some regions. Cyclones in the Arabian Sea increased by more than 50 per cent, with very severe cyclones increasing by 150 per cent. 

The recent IPCC reports also warn us about multiple extremes overlapping. These compound events are already happening in India. With cyclones Tauktae and Yaas in May 2021, we saw storm surges to the height of 5 metres and above, pushing water on to the land. The storm surge flooding over the coast was aggravated by the heavy rains from the cyclones and a background rising sea level. 

It is not just the coastal cities, but rural areas are also hit badly. During the Maharashtra floods in July 2021, the India Meteorological Department recorded 1,074 mm of rain at the Mahabaleshwar hill station in just two days. You can visualise that as more than a metre in height of rainfall. This station has been monitoring rainfall for over a century, and the recent rains broke all-time records. All that water ran down the hills causing landslides and overflowing the rivers, thereby flooding the downstream towns, killing more than 200 people.

I live in Pune, where I used to think that it is climate safe. During June–July, Pune received 34 per cent more rain than normal. During the heavy rains, the roof of our maid Shakuntala’s house leaks, and the rooms get flooded. It is the poor that are always hit the first and the worst. Climate hazards are also leading to the migration of marginal agricultural communities from northern states of India to the Indian megacities like Mumbai that are facing bigger threats due to climate change. The population exposed to floods has increased by 24 per cent since the turn of the 21st century—due to rising floods and population. India has the largest population at the highest risk, followed by China, Bangladesh, and Pakistan.

We might think that the recent floods in India, Europe and China, and the heatwaves in Canada and the US are a wake-up call. We are way past that, and in fact, we keep pressing the snooze button several times. Europe had a massive heatwave killing about 70,000 people in 2003. Mumbai had its devastating flood in 2005, killing more than a thousand, and now floods are an annual affair for the city. Research shows that human-induced climate change is behind these events. Did we learn? 

What do we do now? While curbing emissions is essential so that we don’t accelerate climate change further, we need urgent measures to evaluate and adapt to the increased risk due to intense cyclones, floods, and heatwaves in the near future. While climate change is global, the challenges are always local. The IPCC reports provide only a large-scale assessment, and it is our task to identify the local challenges and disaster-proof those regions where the risk and vulnerability are the highest.

Sometimes citizen science networks can help, where government agencies cannot reach. There are several examples from Kerala and Maharashtra where citizen networks are monitoring the rains, rivers and landslides, and sending flood alerts to people in vulnerable areas. This can work beautifully with the assistance of scientists, engineers, and government bodies. Evidence shows that this has saved lives. We need to empower and make every district of India climate-equipped.

The writer s a climate scientist at the Indian Institute of Tropical Meteorology and lead author, contributor, and reviewer of recent IPCC reports