In News:

The Union Government has included heatwaves and lightning among the notified natural calamities eligible for relief under the operational guidelines of the State Disaster Response Fund (SDRF) and National Disaster Response Fund (NDRF) for the 2026–31 award period. The move follows the 16th Finance Commission’s recommendation, recognising the increasing frequency and intensity of extreme weather events.

What Has Changed?

• The notified list has expanded from 12 to 14 categories. With the addition of heatwaves and lightning, states can now use SDRF resources to provide relief to people affected by these hazards.
• NDRF assistance can supplement state resources where applicable, while heatwave-related mitigation projects can also receive support through Disaster Mitigation Funds.
• This is important because it shifts heatwaves and lightning from being primarily treated as emerging climate risks to hazards that are formally integrated into India's disaster-relief financing framework.

Heatwaves and Lightning as Disaster Risks

• Heatwaves are prolonged periods of abnormally high temperatures relative to a region's normal climate. In India, they occur mainly between March and June, with May generally being the peak month. The IMD determines heatwave conditions using region-specific temperature thresholds.
• Lightning is a rapid atmospheric electrical discharge resulting from the separation and accumulation of opposite electrical charges. It can occur within clouds, between clouds, between clouds and the surrounding air, or between clouds and the ground. Its increasing impacts make early warning, public awareness and lightning-safe infrastructure particularly important.

Why is the decision significant?

The inclusion strengthens India's disaster risk financing and climate adaptation framework. It enables states to respond financially to increasingly frequent climate-related hazards rather than relying only on post-disaster arrangements.

However, relief financing alone cannot address the underlying risk. Effective disaster management requires heat-action plans, early-warning systems, resilient urban infrastructure, public cooling measures, lightning alerts, safer housing and electrical infrastructure, and community-level preparedness.

In News:

In early 2026, a groundbreaking study published in Science Advances revealed a perilous synergy between the ocean and the atmosphere: Marine Heatwaves (MHWs) are now acting as high-octane fuel for tropical cyclones. This phenomenon has led to a 60% increase in billion-dollar disasters due to the "rapid intensification" of storms.

Understanding Marine Heatwaves (MHWs)

A Marine Heatwave is defined as a prolonged period (lasting days to months) of abnormally high ocean temperatures in a specific region.

• The Threshold: Typically, an anomaly of 1°C to 3°C above the long-term seasonal average is characterized as an MHW.
• Duration and Intensity: These events are not just about surface spikes; they often involve a "heat dome" effect within the water column, measured by their cumulative intensity and annual frequency.

The Mechanics of Formation

MHWs form when the ocean’s natural cooling mechanisms break down. This is driven by both atmospheric and oceanic factors:

• Weakening Winds: Strong winds normally cool the ocean via evaporation and by mixing the warm upper layer with cooler, deeper waters. When winds fail, this mixing stops.
• Ocean Stratification: Without wind-driven mixing, the top layer of the ocean becomes thin and "trapped."
• Solar Heating: This thin surface layer absorbs solar radiation rapidly. Because it cannot transfer heat to the depths, the temperature spikes, creating localized extreme heat.
• Global Drivers: Climate change ensures the oceans absorb 90% of excess global heat. Events like El Niño and shifts in atmospheric pressure (e.g., the North Pacific High) further trigger these massive pools of warm water.

How MHWs "Supercharge" Tropical Cyclones

The most critical takeaway for disaster management is the role of MHWs in Rapid Intensification (RI).

• Fueling the Engine: Tropical cyclones draw energy from the evaporation of warm ocean water. Passing over an MHW is like a car hitting a "gas station"; it provides an abundance of energy that boosts wind speeds by 20% and rainfall by 12%.
• Stalling and Decay: These "supercharged" storms tend to move more slowly over land and decay at a much lower rate, leading to catastrophic flooding.
• Economic Fallout: MHW-influenced cyclones are 1.6 times more likely to become billion-dollar disasters. This was evidenced by the back-to-back devastation of Hurricanes Helene and Milton in late 2024, where record-high sea surface temperatures in the Gulf of Mexico led to unprecedented destruction.

Ecological and Economic Implications

Beyond storm intensification, MHWs trigger a cascade of environmental crises:

• Ecosystem Collapse: MHWs are the primary cause of massive coral bleaching and the death of kelp forests, which are vital carbon sinks.
• Harmful Algal Blooms (HABs): Toxic algae thrive in warm water. These blooms produce neurotoxins like domoic acid, which contaminate the food chain and force the closure of commercial fisheries.

Biodiversity Loss: While some species migrate north ("the Winners"), cold-water species like salmon face mass die-offs ("the Losers").

In News:

India is increasingly facing more frequent, intense, and prolonged heatwaves, posing a significant threat to public health, economic productivity, agricultural stability, andenvironmental sustainability. This trend underscores the broader implications of climate change, particularly for developing economies with large vulnerable populations.

Understanding Heatwaves

A heatwave is defined as a prolonged period of abnormally high temperatures, often accompanied by high humidity. As per the India Meteorological Department (IMD):

• A heatwave is declared when the maximum temperature reaches at least 40°C in plains and 30°C in hilly regions.
• The severity is determined by how much the temperature exceeds the normal.

Impacts of Heatwaves

• Public Health:
  • Prolonged heat exposure increases the risk of heatstroke, dehydration, and worsens cardiovascular and respiratory illnesses.
  • Vulnerable groups include the elderly, outdoor workers, and those without access to cooling.
• Livelihoods and Employment:
  • According to the World Bank, India could lose 34 million jobs by 2030 due to heat-stress-related productivity declines.
  • The informal sector and outdoor labourers are especially at risk.
• Agriculture and Food Security:
  • Heat stress leads to reduced crop yields, livestock deaths, and increased irrigation demand.
  • It threatens the food supply chain and rural incomes.
• Water Scarcity:
  • 54% of India’s land is under high to extremely high water stress, as per the World Resources Institute (WRI).
  • Heatwaves exacerbate droughts and deplete groundwater sources.
• Environmental Degradation:
  • Higher temperatures increase the risk of wildfires, especially in forested and arid zones.
  • Ecosystem services and biodiversity are under stress.
• Infrastructure and Energy:
  • Rising temperatures lead to increased energy demand for cooling, straining power grids.
  • Urban infrastructure suffers due to heat-induced wear and tear.