Was India’s hot summer of 2023 a portend of things to come?

General Studies Paper 3

INTRODUCTION

• It will be fair to say that many of us have been looking forward to the monsoon this year, eager to put behind us one of the hottest summers ever on record. With each passing year, India has been experiencing more and more instances of severe heatwaves, rendering these months more and more dreadful.

THE REPORTS

• A recent report from the India Meteorological Department (IMD) indicated an increasing trend in the number and duration of heatwaves, based on data from March to June from 1961 to 2020.
• This year, heatwaves started as early as on March 3, and many areas reported temperatures that were higher than average. The number of days with temperatures exceeding 30 degrees Celsius has also increased of late.
• The U.N. Intergovernmental Panel on Climate Change’s Sixth Assessment Report warned of prolonged rain-free periods along with excessive rainfall in many parts of the world. In recent decades, India has recorded several such extreme events.

• An October 2017 study conducted by the Indian Institute of Tropical Meteorology (IITM), Pune, reported that there was a three-fold increase in widespread extreme events from 1950 to 2015.

CHANGING WEATHER PATTERNS

• Climate change is increasing both the frequency and the intensity of extreme weather events.
• In India, for one, normal monsoon patterns have given way to, among others, delayed onset, short but intense bursts of rain, and delayed withdrawal.
• Some weather events have also become drier and others wetter thanks to the effects of climate change on the water cycle, which leads to more evaporation and eventually causes more precipitation.
• Some areas also experience heavier than normal precipitation while others are becoming prone to unexpected droughts.
• High monsoon rainfall variability and continuous warming raise the probability of dry and hot extremes, with profound implications for agriculture, water resources, and India’s overall economy.
• There is also a strong connection between land and ocean heatwaves, driven by atmospheric circulation, increase in sea-surface temperature, and feedback mechanisms that exacerbate the intensity and duration of extreme temperatures.

ROLE OF MARINE HEATWAVES

• The oceans play a key role in the formation of monsoon winds and in keeping the monsoon alive.
• When extreme heat warms their waters, the change in temperature can lead to cascading effects, such as marine heatwaves, ocean acidification, sea-level rise, and ice melting faster at the poles.
• Marine heatwaves are periods of temperature much higher than the average seasonal temperature in that region.
• The Indian Ocean recorded six marine heatwaves over a period of 52 days in 2021. They used to be rare in this water-body but today are an annual occurrence.
• A low pressure develops over the Indian subcontinent when the land heats up during the summer. The moisture for monsoon rains is thus carried by the winds as they blow in from the Indian Ocean.
• However, rainfall over the land decreases when ocean heatwaves occur, as the winds are drawn to areas over the ocean instead of land.

CLIMATE RISK AMPLIFICATION

• Amplification is what happens when certain climate- related factors and/or events interact with each other or happen at the same time, intensifying or exacerbating the overall risks and consequences associated with climate change.
• A good example is the warm and dry conditions that have put Canada on course for its worst-ever wildfire destruction this year.
• Such amplification happens in the form of various feedback loops and interconnected processes in the earth’s climate system and also occur as a result of an El Niño, prolonged hot days, dry monsoons, and/or ocean heatwaves occurring together, compounding risks across sectors.
• Such a combination will also affect water availability, soil moisture, and crop output while increasing food prices and lowering incomes.
• The co-occurrence of heatwaves and droughts can also lead to wildfires, tree mortality, and a higher risk of thermal power-plant failures.
• Ultimately, the risks can push sensitive and vulnerable systems over a tipping point, ultimately avalanching into drastic consequences for socio-ecological systems.

WAY FORWARD

• Amplified climate risks underscore the urgency of taking proactive measures to mitigate greenhouse gas emissions, adapt to changing conditions, and enhance resilience in both natural and human systems.
• Identifying compound event hotspots and monitoring them are important to frame suitable adaptation strategies.
• By understanding and addressing these amplification mechanisms, we will be able to reduce the overall risk associated with climate change and build a more sustainable and resilient future.