Recent studies have brought into light alarming trends in heatwave patterns in India. Researchers from IIT-Bombay and ETH Zurich have identified a new category of heatwaves termed ‘oppressive heatwaves’. These are characterised by both high temperatures and elevated humidity. Such conditions are expected to become more frequent due to global warming. The implications for human health, particularly mortality rates, are .
Definition of Heatwaves
Heatwaves are classified based on temperature thresholds. The India Meteorological Department (IMD) defines a heatwave as a period of three or more days where temperatures exceed specific limits. In plains, this threshold is above 45 degrees Celsius, while in hilly regions, it is above 40 degrees Celsius. This classification is crucial for understanding the severity and impact of heatwaves across different regions.
Types of Heatwaves
- The researchers categorised heatwaves into two types – oppressive and extreme.
- Oppressive heatwaves occur with both high temperature and high humidity.
- Extreme heatwaves are characterised by high temperatures but low humidity.
- The distinction is vital as oppressive heatwaves pose a higher risk to human health, particularly in densely populated areas.
Methodology of Research
The study utilised historical data from 1951 to 2013, sourced from the IMD and other meteorological agencies. The researchers employed the Community Earth System Model Large Ensemble Numerical Simulation (CESM-LENS) data to project future heatwave events. They assessed changes in heatwave characteristics under two global warming scenarios – a 1.5 degrees Celsius rise and a 2 degrees Celsius rise.
Projected Changes in Heatwaves
The findings indicate a dramatic increase in oppressive heatwave days. Under a 1.5 degrees Celsius warming scenario, oppressive heatwave days could increase five-fold between 2035 and 2065, and also by the end of the century. In contrast, extreme heatwave days are projected to remain relatively stable. Under a 2 degrees Celsius warming scenario, oppressive heatwave days could increase eight-fold.
Impact on Human Mortality
The research puts stress on a strong correlation between oppressive heatwave days and heat-related mortality. Historical data from 1967 to 2007 revealed that mortality rates rise during oppressive heatwaves compared to dry heatwaves. The study warns of an exacerbated risk of heat-related deaths in the future if current trends continue.
Adaptation Measures
The researchers advocate for urgent adaptation measures. The notable rise in oppressive heatwave days signals an immediate need for strategies to mitigate health risks. Limiting global warming to 1.5 degrees Celsius could reduce the likelihood of oppressive heatwaves by 44% and extreme heatwaves by 25% by the century’s end.
Questions for UPSC:
- Examine the impact of climate change on agricultural productivity in India.
- Discuss in the light of recent studies how urbanisation contributes to the urban heat island effect.
- Critically discuss the role of government policies in mitigating the effects of climate change.
- With suitable examples, discuss the relationship between public health and environmental changes.
Answer Hints:
1. Examine the impact of climate change on agricultural productivity in India.
- Climate change leads to altered precipitation patterns, affecting crop yields.
- Increased temperatures can stress crops, reducing their growth and productivity.
- Extreme weather events, such as floods and droughts, disrupt farming cycles.
- Pests and diseases may proliferate due to warmer conditions, harming crops.
- Adaptation strategies, like drought-resistant crops, are essential for resilience.
2. Discuss in the light of recent studies how urbanisation contributes to the urban heat island effect.
- Urbanisation increases impervious surfaces, leading to heat retention.
- Vegetation loss in cities diminishes natural cooling effects.
- Higher energy consumption in urban areas contributes to increased heat emissions.
- Studies show temperature differences of 2-5 degrees Celsius between urban and rural areas.
- Mitigation strategies include increasing green spaces and reflective building materials.
3. Critically discuss the role of government policies in mitigating the effects of climate change.
- Government policies can promote renewable energy sources, reducing dependency on fossil fuels.
- Implementation of carbon pricing can incentivize emission reductions from industries.
- Regulations on land use and urban planning can help manage environmental impacts.
- Investment in climate-resilient infrastructure is crucial for adaptation.
- International cooperation and agreements, such as the Paris Accord, are essential for global efforts.
4. With suitable examples, discuss the relationship between public health and environmental changes.
- Air pollution from industrial activities leads to respiratory diseases, as seen in cities like Delhi.
- Water contamination from agricultural runoff can cause gastrointestinal illnesses, impacting communities.
- Heatwaves, exacerbated by climate change, increase heat-related illnesses and mortality rates.
- Vector-borne diseases, like malaria, may spread due to changing climate conditions.
- Urban planning that includes green spaces can improve mental health and overall well-being.
