Scientists have identified that human-made climate change is accelerating natural weather phenomena, leading to a surge in heatwaves across Asia, Europe, and North America. For UPSC Exams, it is necessary to know why 2023 has become exceptionally hot and why these record temperatures will continue to worsen, even if significant reductions in planet-warming gas emissions are achieved.
El Nino and its Influence
After experiencing a record-hot summer in 2022, the Pacific warming phenomenon known as El Nino has reemerged, contributing to ocean warming. Although the El Nino event is still in its early stages, experts, including Robert Rohde from the US temperature monitoring group Berkeley Earth, suggest that it might have added some warmth to the North Atlantic region. However, the overall effect of El Nino on the current heatwave is likely to be relatively small.
Dust and Sulphur Impact
The warming of the Atlantic Ocean may have been intensified by two factors: reduced dust particles from the Sahara desert and a decline in sulphur aerosols emitted from shipping fuel. An analysis by Berkeley Earth’s Robert Rohde observed abnormally low levels of Sahara dust in recent months due to weaker Atlantic trade winds. Additionally, new shipping restrictions implemented in 2020 have significantly reduced toxic sulphur emissions. While these factors alone do not explain the entirety of the North Atlantic heat spike, they may have contributed to its severity.
Influence of “Stagnant” Anticyclones
Warming oceans influence weather patterns over land, leading to heatwaves, droughts, and storms. The hotter atmosphere absorbs moisture and redistributes it, resulting in prolonged heatwaves and localized rainfall. Experts have emphasized the significance of persistent anticyclone systems in causing intense and prolonged heatwaves. Stagnant high-pressure areas over continents cause the air to sink and warm, eradicating clouds and intensifying summer sunshine. As a result, heatwaves can become stationary for weeks, exacerbating their impact. Climate scientists note that high-pressure conditions in Europe have caused hot air from Africa to remain trapped, leading to continuous heat build-up in sea, land, and air.
Climate Change’s Role
The Intergovernmental Panel on Climate Change (IPCC) has stated in their recent global summary report that climate change has increased the frequency and intensity of deadly heatwaves across most land regions since the 1950s. The current heatwaves are a combination of multiple factors acting concurrently, but climate change has amplified their effects. Higher global temperatures caused by climate change result in longer and more intense heatwaves. However, it is important to recognize that while climate change is a significant driver, it is a variable that human actions can influence by reducing greenhouse gas emissions.
The Way Forward
Melissa Lazenby, a senior lecturer in climate change, highlights that human influence on climate and weather patterns has taken us into uncharted and more extreme territory. However, she emphasizes that humans have the ability to mitigate their impact by reducing emissions and preventing the occurrence of even more severe and prolonged heatwaves. The IPCC warns that if significant cuts in carbon emissions are not achieved, the current El Nino event could further contribute to global warming in 2024. Governments and societies must take action to limit climate change and adapt to the reality of more frequent and intense heatwaves in the future.
