India’s heatwaves will intensify four-fold by 2100, says its first climate assessment report

India’s average temperature has already increased by around 0.7 degree Celsius during the 1901–2018 period due to greenhouse gas emissions and by the end of 2100 it is expected to rise by approximately 4.4 degree Celsius – relative to 1976–2005 average, in the worst-case scenario – warns the first-ever climate change assessment report by the Indian government.

The report Assessment of Climate Change over the Indian Region prepared by the Union Ministry of Earth Sciences or MoES warned that the rapid changes in the temperature would mean increasing stress on India’s “natural ecosystems, agricultural output, and freshwater resources, while also causing escalating damage to infrastructure.” This ultimately means a serious impact on “country’s biodiversity, food, water and energy security, and public health.”

It said that several regions in India are global biodiversity hotspots with numerous endemic species of plants and animals and with the “climate changing more rapidly than the usual pace of evolutionary adaptability of many species, they may face increasing threats on account of these changes.”

The global average temperature has risen by around one degree Celsius since pre-industrial times. In 2015, at the Paris Agreement, the world decided to limit global warming to two degree Celsius below pre-industrial levels and to pursue efforts to limit the increase to 1.5 degree Celsius. At current greenhouse gas emissions trajectories, global average temperature may rise 3-5 degree Celsius and perhaps higher if tipping points are triggered.

The MoES report cautioned that by the end of 2100, the “frequency of summer [April–June] heat waves over India is projected to be three to four times higher” and the “average duration of heatwave events is also projected to approximately double.” The impact of heatwave stress is expected across India but particularly over the densely populated Indo-Gangetic river basin. According to the report, the sea surface temperature of the tropical Indian Ocean has also risen by one degree Celsius, on average, during 1951–2015, which is higher than the global average warming of 0.7 degree Celsius, over the same period.

The rise in temperature is also playing havoc with India’s rainfall which is significant for India’s agriculture sector on which millions are dependent. The report noted that the summer monsoon precipitation (June to September) over India has declined by around six percent from 1951 to 2015, with notable decreases over the Indo-Gangetic Plains and the Western Ghats.

“There has been a shift in the recent period toward more frequent dry spells [27% higher during 1981–2011 relative to 1951–1980] and more intense wet spells during the summer monsoon season,” said the report.

It stressed that the overall decrease of seasonal summer monsoon rainfall during the last six to seven decades has led to an increased propensity for droughts over India.

“Both the frequency and spatial extent of droughts have increased significantly during 1951–2016. In particular, areas over central India, Southwest coast, Southern peninsula and Northeastern India have experienced more than two droughts per decade, on average, during this period. The area affected by drought has also increased by 1.3% per decade over the same period. Climate model projections indicate a high likelihood of an increase in the frequency [more than two events per decade], intensity and area under drought conditions in India by the end of the 21st century,” said the MoES report.

Climate scientist Roxy Mathew Koll of the Pune-based Indian Institute of Tropical Meteorology, who is also the author of the Intergovernmental Panel on Climate Change Special Report on Oceans and Cryosphere in a Changing Climate, explained to Mongabay-India that until now we were dependent on IPCC report for assessment of climate change but the problem is that it is a global overview and doesn’t include region-specific details.

“We urgently needed something like that considering that rise in extreme weather events is already visible,” said Koll, who is one of the co-authors of the MoES report. “We required a report that quantified the changes on the regional scale and this report gives an overall view as to how climate change is happening in different spheres across India. Whether it is the changes over the Himalayas, the coastal areas, or the rainfall pattern, in this report we are quantifying it. Now we have the exact details as to what extent climate parameters are changing.”

Severe impact on Himalayas

The report highlights that the Hindu Kush Himalayas have experienced a temperature rise of about 1.3 degree Celsius during 1951–2014. “Several areas of HKH have experienced a declining trend in snowfall and also retreat of glaciers in recent decades. In contrast, the high-elevation Karakoram Himalayas have experienced higher winter snowfall that has shielded the region from glacier shrinkage. By the end of the 21st century, the annual mean surface temperature over HKH is projected to increase by about 5.2 degree Celsius...human-induced climate change has led to accelerated warming of the Himalayas and the Tibetan Plateau at a rate of 0.2 degree Celsius per decade during 1951–2014,” said the report.

It said that the future warming in the HKH region, “which is projected to be in the range of 2.6–4.6 degree Celsius” by the end of 2100, “will further exacerbate the snowfall and glacier decline leading to profound hydrological and agricultural impacts in the region.”

Resources under stress

The report by the Union Ministry of Earth Sciences observed that the impact of climate change on the availability of freshwater is a critical area of concern for India and the growing propensity for droughts and floods because of changing rainfall patterns caused by climate change would be “detrimental to surface and groundwater recharge, posing threats to the country’s water security.”

“Likewise, the country’s food security may be placed under progressively greater pressure due to rising temperatures, heat extremes, floods, droughts and increasing year-to-year rainfall variability that can disrupt rain-fed agricultural food production and adversely impact crop yield,” the report warned. It further explained that the rising temperatures are also likely to increase energy demand for space cooling, which if met by thermal power would mean a further increase in greenhouse gas emissions.

“In addition, thermal power plants require substantial amounts of water for cooling to generate electricity. Power plants sited inland draw freshwater largely from dam reservoirs, rivers and canals. A rise in water withdrawal by power plants would directly compete with water withdrawal for agriculture and domestic consumption, particularly in water-stressed areas. On the other hand, power plants sited around the coast that use seawater for cooling are vulnerable to damage from sea-level rise, cyclones, and storm surge,” said the report adding that this could mean that climate change could impact the “reliability of the country’s energy infrastructure and supply.”

Forests and urban spaces

According to the MoES report, India’s climate change adaptation and mitigation response is achievable by a greater emphasis on widening observational networks, sustained monitoring, expanding research on regional changes in climate and their impacts, and by continued investment in education and outreach programmes.

“For instance, networks of tide gauges with GPS along the Indian coastline would help monitor local changes in sea level, climate models would help project future changes, and outreach would help inform the requisite adaptation measures in coastal communities and cities. Outreach and communication of climate change risk to district and village-level communities would facilitate water-harvesting and farming decisions needed to adapt to a changing climate,” it explained.

The report stressed that as “cities being uniquely impacted by heat stress and localised flooding”, there is a pressing need for research and strategies that are directed towards “improving resilience in Indian cities.”

Koll stressed that oceanic changes are an important area and the report focuses on that. “The origin of many of the extreme events, rainfall, cyclones, heatwaves, sea-level rise is the oceanic changes. The reason is that they absorb about 93 percent heat from global warming and then respond to it. For instance, the intensity cyclones hitting India’s coasts are intensifying quite rapidly. There are many gaps in our ocean observations and we need to plug them by improving observations both over coastal regions and in the open ocean,” said Koll.

He further said that the first assessment report by them takes care of the physical aspects of climate change while the next one could focus on how these changes are impacting sectors like agriculture, food, water and power.

The report emphasised that low impact development and green building infrastructure can reduce both urban heating and air pollution. “A reduction in air pollution would greatly benefit human and environmental health, improve the efficiency of solar energy generation, and even potentially aid in increasing the quantum of monsoon rainfall over India. An increase in rainfall together with measures for water harvesting would aid the restoration of groundwater levels,” it added.

Anumita Roychowdhury, of the Centre for Science and Environment, a Delhi-based environment think-tank, said, with this report the government is officially recognising the interconnectedness of the diverse nature environmental impacts and its deep link with climate change.

“This report reinforces the idea that we need alignment at the policy and implementation level across sectors that have an impact on the environment. This is absolutely critical as different sectors cannot remain in silos anymore. Post this report, we look forward to well-defined indicators for an aligned action with focused policy interventions and effective leveraging of resources and budgets to deliver on a larger goal. This should be the basis of the action of the government going forward,” Roychowdhury told Mongabay-India.

The report suggested that policymakers focus on forests and urban green spaces. It said that aside from mitigating climate change through carbon sequestration, trees also enhance resilience to flash floods and landslides, improve resilience to droughts, improve the resilience of coastal infrastructure, reduce vulnerability to extreme heat by reducing ambient temperatures, and support native wildlife and biodiversity.

“In short, forests and urban green spaces will deliver substantial economic benefits to the country by mitigating a wide range of the expected impacts of climate change in India and is the safest, most reliable means of realising several of India’s sustainable development goals,” the report said.

Aarti Khosla, who is the director of Climate Trends, told Mongabay-India that the “report is a good step as it finally lays to rest all confusion about the relationship of climate change with extreme weather events and climate vulnerabilities in terms of increase in droughts and lean rainfall period etc.”

“However, at the time of post-Covid-19 lockdown, when the focus is on economic recovery, it stops short of establishing linkages between the importance of sustainable and green recovery,” said Khosla while explaining that the report should have focused properly on the importance of pursuing economic growth which is sustainable for the planet.

She said such scientific evidence will prove useful to simplify and educate the citizens on what is happening to our environment. “The pandemic has revealed that society does have a collective conscience and people are ready to shift their attitudes. The impacts of climate change don’t fall evenly and will have to be communicated across the vast swathes of our population,” Khosla said.

This article first appeared on Mongabay.