Following a May characterized by excessive rainfall in many regions, a sharp transition to searing heatwaves has been observed, particularly across North India, with temperatures exceeding 44°C in Punjab, Haryana, Rajasthan, and Delhi. This abrupt shift underscores how climate change is fundamentally altering weather systems, leading to more frequent and intense extreme weather events.
Scientists have long warned that human-caused climate change, primarily through the emission of greenhouse gases from burning fossil fuels, is increasing the frequency and intensity of extreme weather events such as heat waves and large storms. These gases trap heat in the atmosphere, causing a rise in global average temperatures, which in turn disrupts normal weather patterns. This disruption manifests in various ways, including altered rainfall patterns, prolonged droughts, and more intense heat waves.
The recent weather patterns exemplify these changes. The unusually wet May across the Indo-Gangetic Plains, which brought relief from pre-monsoon heat, was followed by a stalling of the monsoon's progress after it reached Mumbai and parts of Northeast India. Simultaneously, the frequency of western disturbances decreased significantly. This created conditions ripe for a severe heatwave, with hot, dry winds flowing continuously from the Thar Desert, where temperatures were already hovering near 48°C, toward the eastern and central parts of the country.
One of the key mechanisms by which climate change exacerbates heatwaves is through increased atmospheric moisture. For every 1°C rise in average temperature, the atmosphere can hold approximately 7% more moisture. While this can lead to heavier rainfall in some areas, it also increases humidity, making heatwaves feel more oppressive and dangerous. This added humidity hinders the human body's ability to cool itself through sweating, posing serious health risks, especially for vulnerable populations such as the elderly, outdoor workers, and those with chronic illnesses.
The interplay between rainfall and heatwaves is complex and influenced by soil moisture. Wetter regions, humid heatwaves are more likely to follow periods of suppressed rainfall. Rainfall increases moisture in soils making conditions more humid. Less rainfall and fewer clouds allow the land to warm, thereby increasing temperatures.
The current situation highlights a concerning trend: the increasing unpredictability and intensity of weather events. The fact that heatwave spells were previously confined to Rajasthan but have now expanded to include Punjab, Haryana, and Delhi, with the India Meteorological Department (IMD) issuing red alerts for consecutive days, demonstrates this shift. Such changes necessitate a re-evaluation of preparedness and response strategies, particularly in regions that were not historically prone to extreme heat.
Addressing the root causes of climate change through reducing greenhouse gas emissions remains the most critical long-term solution. This requires a transition away from fossil fuels towards renewable energy sources, as well as implementing policies that promote energy efficiency and sustainable land use. Furthermore, it is crucial to develop and implement adaptation strategies to help communities cope with the increasing impacts of extreme weather events. These strategies may include improving heatwave early warning systems, providing access to cooling centers, promoting water conservation, and investing in infrastructure that can withstand more extreme conditions.
