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“A concoction of natural and human-made reasons specific to India make it particularly vulnerable to the climate crisis”.

October 31, 2020

Dr. Chirag Dhara is a physicist and climate scientist – a rare combination. He is currently working at the Indian Institute of Tropical Meteorology (IITM), Pune. Chirag started his academic career as a theoretical physicist with a PhD at the Institute of Photonic Sciences, Barcelona, Spain. He subsequently switched his research focus to the climate sciences with a second PhD at the Max Planck Institute for Biogeochemistry in Germany. His larger concerns are climate impacts, environmental protection, and climate justice.

Chirag is one of the authors of India’s first comprehensive climate assessment report released three months ago, which is the regional analog of the IPCC’s global scale reports. It can be accessed at: https://link.springer.com/book/10.1007%2F978-981-15-4327-2.

The scientific understanding is that both the Bay of Bengal and the Arabian sea will see a greater fraction of cyclones intensifying into the most severe categories.

Praveen Gupta: What are the Climate related vulnerabilities that India faces?

Chirag Dhara: A concoction of natural and human-made reasons specific to India make it particularly vulnerable to the climate crisis. High baseline summer temperatures, its varied geography over a vast area, a heavy dependence of agriculture on stable monsoons and a coastline stretching 7000 km are some.

Runaway pollution, unplanned development, a large informal economy, deforestation, insufficient disaster-preparedness, and a significant proportion of its population living in poverty are other factors adding to India’s unique vulnerability.

PG: What do you expect happening to the Indo-Gangetic belt and the Sunderbans, in particular?

CD: I believe that the Indo-Gangetic belt and the Sundarbans will be among the most affected parts of the country since multiple climate change impacts are playing out in those regions. The Indo-Gangetic plains are hot and humid. Humid heat is much more dangerous than dry heat, and a simultaneous spike in heat and humidity can significantly raise the risk of cardiovascular and neurological conditions. In fact, the deadly heat waves in the summer of 2015 across India and Pakistan, with high fatalities, were a result of the combination of high temperature and humidity that lasted several days.

Humid heat is much more dangerous than dry heat, and a simultaneous spike in heat and humidity can significantly raise the risk of cardiovascular and neurological conditions.

The Indo-Gangetic plains are projected to see higher intensity of ‘humid heat waves’ with global warming. The Sundarbans in particular is seeing a highly accelerated pace of sea level rise relative to the global average (attributed not just to global warming but also to extensive upstream damming of rivers flowing into the Sundarbans and ground water extraction). In addition, there is the propensity for cyclones, which are likely to intensity with warming.

PG: Will higher precipitation lead to both floods and droughts?

CD: Yes. It is a worldwide phenomenon that rainfall patterns are tending towards shorter intense bouts of rainfall interspersed with lengthening dry spells. The one increases the propensity for floods, and the other for droughts. In addition, higher temperatures tend to dry out soil and vegetation more, making droughts more intense and wildfires more likely.

It is a worldwide phenomenon that rainfall patterns are tending towards shorter intense bouts of rainfall interspersed with lengthening dry spells.

PG: Would the same location be faced with both – hot dry spells and excessive wet?

CD: It may well be for the reasons I’ve outlined above. But regional climate projections are a scientifically complex problem and much more work is necessary. We need more scientific groups around the country working in tandem to arrive at better assessments of regional flood and drought risk.

PG: What do your projections say about storms/hurricanes in Bay of Bengal and the Arabian Sea?

CD: The scientific understanding is that both the Bay of Bengal and the Arabian sea will see a greater fraction of cyclones intensifying into the most severe categories. While such trends are already seen in the observation record, they are not yet significant enough to be attributable to anthropogenic global warming. We cannot yet discount the possibility that most of the changes seen thus far may have resulted from natural variations in the Earth’s climate. However, the fundamental science is clear and trends in cyclone intensification are expected to strengthen with continued heating.

The fundamental science is clear and trends in cyclone intensification are expected to strengthen with continued heating.

 PG: How much of what manifests here would be a result of our own doing? Is it all about pollution?

CD: Most of India’s industrial era temperature rise has been attributed to rising GHGs from human activity. 

The changing rainfall patterns over India on the other hand is increasingly being understood as a complex interplay between a rising tendency due to GHGs counteracted in part by the radiative (climate) effects of particulate matter pollution (what we perceive as ‘air pollution’). Hence, strong regional variations.

Flood and drought propensity are, of course, a consequence of changing rainfall patterns. In the case of floods, clear increases in the extent and pace of Himalayan glacier melt due to rapid warming will also increasingly play a role. However, an important caveat when it comes to floods is that it is also heavily dependent on the ‘developmental’ paradigm at work. Deforestation and concretisation both increase flood propensity.

As I said, it is not yet clear if the rising cyclone intensity trends seen in the observations can be attributed in part to human activity or if natural variations alone are responsible for them. It is likely that global warming has played a role but we don’t have enough information yet to draw robust conclusions.

Sea levels are rising in line with expectation from theory and models, so are robustly attributed to anthropogenic GHG emissions.

GHGs and particulate matter pollution are the key aggravators for changes in different climate variables. These rise with industrial activity.

PG: A growing population, rising aspirations would have implications for energy, infra, agriculture and livestock – these are the key Climate aggravators?

CD: GHGs and particulate matter pollution are the key aggravators for changes in different climate variables. These rise with industrial activity. There are technologies that may help in rapid reduction in particulate matter pollution. However, there is no proven technological quick fix that can rapidly reduce atmospheric GHGs. Rising industrial activity is being driven more by rising aspirations than by population. This is because population growth is highest among the lowest economic classes, which have very low carbon and resource footprints. 

PG: Would afforestation help? What needs to be done and how quickly?

CD: I quote a paragraph from the last chapter of our recent book “Assessment of Climate Change over the Indian Region”:

Ambitious afforestation efforts offer myriad benefits. Aside from mitigating climate change through carbon sequestration, trees also enhance resilience to flash floods and landslides by improving soil retention, improve resilience to droughts by increasing percolation of surface water into the soil, improve resilience of coastal infrastructure and habitation by reducing coastline erosion due to storm surges and sea-level rise, 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.

An ecologist would be better placed to answer how and where to make this happen.

Ambitious afforestation efforts offer myriad benefits... 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.

PG: Is there a way to quantify the precise physical risk posed by Climate risk and what kind of resilience does it call for?

CD: Certainly, but this has not been done for India to my knowledge. Quantifying risk involves quantifying regional scale impacts, and perhaps also exposure of the population in those regions. Resilience doesn’t necessarily have to be high-tech. Ahmedabad’s excellent heat action plan is an inspiration to draw from. I am certain there must be many examples around the country that deserve replication.

PG: Many thanks Chirag for these compelling insights. Here is wishing you all the very best in all your ongoing endeavours.

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