A grid can have thousands of wind turbines and millions of solar panels and still face an electricity shortage when the weather turns against renewable generation. The concern is not simply that wind or solar output falls. It is what happens when the decline comes quickly and continues for several days.

A new study published in Nature identifies these events as “flash energy droughts” and finds that climate change could make some of them last longer. The finding points to a growing challenge for power systems that are adding renewable generation faster than they are building the flexibility needed to manage its variability.

When Renewable Generation Suddenly Drops

An energy drought occurs when wind or solar farms produce unusually little electricity for a sustained period. The researchers add another feature to the definition: the decline must happen unusually quickly.

Using 1985–2014 as a historical baseline, they identified energy droughts when daily wind or solar capacity factors fell below the 10th percentile of the baseline for at least three consecutive days. Events with an unusually rapid decline into that low-output period were classified as flash energy droughts. When wind and solar shortages occurred together, they were treated as compound events.

For a power system, the speed of the decline matters. A gradual reduction gives grid operators more time to adjust generation, move electricity between regions, charge or preserve storage and manage demand. A rapid drop leaves fewer options.

Kavan Javanroodi, an Assistant Professor at Lund University who studies climate-resilient energy systems and extreme climate events, wrote in an accompanying Nature Climate Change commentary that rapid declines in renewable generation can leave electricity systems with little time to respond.

Longer Droughts Create Bigger Grid Problem

The researchers used climate-model projections and an electricity-dispatch model to examine how flash energy droughts could change under different future emissions scenarios. Under the relatively low-emissions SSP1-2.6 scenario, the projected duration of flash energy droughts increases by 25.6% for wind and 29.8% for solar.

The change is much larger for compound events affecting both resources. Their projected duration increases by 155.7% under the same scenario. That figure does not mean renewable electricity production will fall by 155.7%. It refers specifically to the modelled duration of compound flash energy droughts.

The study also estimates that around 70.8% of global wind and solar capacity could be exposed to increasing frequency and duration of flash energy droughts. The significance lies in the overlap between two trends: renewable generation is becoming a larger part of electricity systems, while climate change is altering the weather conditions that drive that generation.

When Wind and Solar Fall Together

Wind and solar are often considered complementary sources. Solar produces most of its electricity during daylight, while wind follows different weather patterns and can generate power at night. When one resource is weak, the other may help compensate. A compound energy drought removes some of that buffer.

The study finds that flash energy droughts can increase unserved energy, flexibility requirements and electricity costs, placing greater pressure on the rest of the power system.

This changes the storage question, too. A battery that shifts solar power from the afternoon into the evening can help with a daily peak. But if wind and solar remain unusually weak for several days, the problem becomes one of energy duration, not simply instantaneous power. A system may need electricity for longer than a conventional short-duration battery can provide it.

India’s Renewable Expansion

India is rapidly increasing its dependence on renewable electricity. As of August 31, 2026, the country had 168.04 GW of installed solar capacity and 58.52 GW of wind capacity, according to the Ministry of New and Renewable Energy. Total renewable capacity, including large hydropower, stood at about 295.55 GW. India’s renewable resources are also exposed to changing climate conditions.

A 2026 study in Applied Energy examining climate impacts on India’s solar and wind resources projected that solar photovoltaic generation potential could decline by up to 10% across the country under the scenarios studied. Changes in wind potential varied substantially by region, with projected changes ranging from about 20% lower to 30% higher. The study also projected increases in solar-generation drought days in several parts of India. But they underline the same planning challenge: renewable generation depends on a climate that is itself changing.

Storage Cannot be the Only Answer

India is already planning for a much larger role for energy storage. The Ministry of New and Renewable Energy, citing the Central Electricity Authority’s National Electricity Plan, puts India’s energy-storage requirement at 82.37 GWh in 2026–27, rising to 411.4 GWh by 2031–32. Of the projected 2031–32 requirement, 236.22 GWh is expected from battery energy storage systems and 175.18 GWh from pumped-storage projects.

Those systems can help bridge the gap between when renewable electricity is generated and when consumers need it. But a multi-day renewable drought requires a broader strategy.

Longer-duration storage can carry electricity through prolonged shortages. Pumped-storage hydropower can provide large-scale flexibility. Transmission can move electricity from regions where renewable generation remains strong to areas facing a shortfall. Demand-response systems can shift some consumption away from stressed periods.

Better forecasting also matters. If grid operators can identify a rapidly developing renewable drought early, they can preserve storage, bring flexible generation online and prepare the network before the shortage becomes acute.

For the Days When Renewables Fall Short

The study also points to the importance of where renewable projects are built. Strategic siting could reduce exposure to flash energy droughts, although the benefits depend on climate conditions, available resources and whether suitable sites can actually be developed. That adds another consideration to renewable-energy planning.

A good solar or wind site is not only one that produces large amounts of electricity under normal conditions. It should also be considered in terms of how its generation behaves during extreme weather conditions and how easily the wider grid can compensate when output falls. For India, the next phase of the renewable transition will therefore require more than adding generation capacity.

It will require a grid that can store electricity for longer, move it across regions, adjust demand and respond quickly when weather-driven generation suddenly drops. The goal is not to eliminate the variability of renewable energy. It is to build a power system capable of working through it.

India is heading into another winter against the backdrop of a changing climate, with scientists warning that rising global temperatures are altering the country’s weather patterns. Heatwaves are becoming a growing public-health concern, yet one question remains hard to answer: “How many heat deaths is India actually recording from extreme heat?”

A new report by the Climate Impact Lab, an initiative of the University of Chicago’s Energy Policy Institute, puts the toll in the thousands. Titled ‘451,000 at Risk’ and published in September 2026, it projects about 15,800 additional deaths in India, with a stated range of ±1,600, between September 2026 and February 2027. The comparison is with the same months of an average year between 1996 and 2025. That makes India the fourth most affected country in the report’s ranking, behind Nigeria, Indonesia and Sudan. The figure comes with an important caveat: it is a modelled estimate, not a count of deaths recorded by India’s health system.

The timing matters. Of India’s projected total, 7,400 deaths fall between December and February, and the Lab expects heat-related deaths in India and Pakistan to keep rising into their summer, beyond the forecast window. It says it will update its projections as the El Niño progresses.

El Niño, the ‘Little Boy’

El Niño is Spanish for ‘the little boy’, but the concern it is causing is far from small as global temperatures continue to reach exceptional levels.

El Niño is a naturally occurring climate pattern associated with unusually warm waters in the central and eastern tropical Pacific Ocean. It can temporarily push global temperatures higher and influence rainfall and temperature patterns across the world, including the Indian monsoon. The Lab describes the current event as a ‘Super El Niño’ that began in June and is expected to last through the northern-hemisphere spring, and notes that it could become the strongest on record.

The report projects that global land temperatures will be about 1.2°C above normal in the coming months, largely because of El Niño. That is comparable to the warming climate change is projected to deliver 20 years from now, and the Lab expects 44 per cent more extremely hot days than in a normal year.

Scientists have increasingly examined El Niño alongside the longer-term influence of human-caused climate change. While El Niño is a natural phenomenon, its effects occur against a warmer global baseline created by the accumulation of greenhouse gases in the atmosphere.

Recent records show the scale of that warming. The EU’s Copernicus Climate Change Service has recorded exceptionally warm months and seasons in recent years, and 2024 was the first calendar year in which the global mean temperature exceeded 1.5°C above the pre-industrial level, according to the Lancet Countdown. Single months or years above 1.5°C do not by themselves mean the Paris Agreement limit has been breached, which is judged on a multidecadal average. On 2 September, the UN Environment Programme (UNEP) published its ‘Limiting Overshoot’ report, which warns that global temperature rise is set to cross 1.5°C, likely within the next few years.

An aerial view of a wildfire burning through dry vegetation, highlighting the growing risk of extreme heat and fire in a warming climate.Image credit:Kelly/Pexels

The changing climate is also being felt in more variable rainfall. According to the India Meteorological Department (IMD), India received 706.9 mm of rain between 1 June and 22 September against a normal of 832.4 mm, a deficit of about 15 per cent. Rainfall has not been uniform across the country: some regions have had significant rain, while others have faced prolonged deficits or intense, short-duration downpours.

Rainfall, temperature and humidity also interact to shape heat exposure. A warmer atmosphere can increase the intensity of certain heat events, while high humidity makes it harder for the body to cool itself through sweating.

The Hidden Mortality Problem

The 2025 report of the Lancet Countdown on Health and Climate Change found that heat-related deaths have risen by 63 per cent since the 1990s, averaging an estimated 546,000 a year between 2012 and 2021.

The Lab projects around 451,000 additional heat-related deaths worldwide, compared with a normal year, from June 2026 to February 2027, the first nine months of the El Niño event. About 239,000 of those (±11,000) fall in the six months from September to February, the same window as India’s figure.

The Global South is expected to be hit hardest. Nigeria, Sudan, Niger and Chad, which the report groups as the Sahel, together face 66,800 additional deaths, of which Nigeria accounts for around 31,400, Sudan 17,500, Niger 10,000 and Chad 8,000. Indonesia is projected to see 19,300 additional deaths, and the Philippines, Vietnam, Thailand and Cambodia together 19,400. Brazil’s projected figure is 13,300.

Emily Grover-Kopec, Director within the Energy & Climate practice at Rhodium Group and co-author of Climate impact lab report said the estimates are based on temperature–mortality relationships and seasonal temperature forecasts from the European Centre for Medium-Range Weather Forecasts’ SEAS5 system. The Lab says it applied those relationships, which account for differences in local climate, vulnerability and adaptive capacity across 24,378 regions, to the forecasts. It says the full methodology will appear in an upcoming peer-reviewed journal, so the analysis has not yet been through that process.

Counting deaths from extreme heat is considerably harder than counting deaths from an accident or an infectious disease.

Part of the difficulty lies in how deaths are recorded. Heat may not appear as the immediate cause of death on a death certificate. A person exposed to extreme temperatures may die from cardiovascular disease, respiratory illness, kidney failure or another complication, making it difficult to establish the role heat played.

When temperatures rise sharply, hospitals may see more patients with dehydration, heatstroke and other heat-related illnesses. But extreme heat can also worsen existing medical conditions, and deaths from those conditions may not be recorded as heat-related.

This creates a gap between observed deaths and excess mortality: the number of deaths above what would normally be expected in a given period.

In India, that gap starts with how deaths are counted. According to an analysis by Rakesh Dubbudu on India Together, the country has no single authority, definition or process for a heat-related death. The National Disaster Management Authority counts deaths tied to declared heatwaves, the National Crime Records Bureau relies on police registers, and the health ministry counts clinically suspected heatstroke. For 2000–2020, the crime records bureau’s total exceeded 20,600, the disaster authority’s was about 17,700 and the IMD’s about 10,500. The Associated Press reported in 2024 that for 2020 the crime records bureau recorded 530 heatstroke deaths while the disaster authority reported four.

The wider system has its own limits. India’s civil registration system recorded 86.6 lakh deaths in 2023, a registration level of 97.2 per cent, but medical certification of the cause of death is far less complete, and heatstroke is hard to certify after death, especially in rural areas where post-mortems are rare.

Beyond the Numbers

The projection of thousands of additional deaths is therefore more than a statistical matter. It raises a larger question: whether India’s public-health and mortality surveillance systems can keep pace with a changing climate.

Michael Greenstone, a co-founder of the Climate Impact Lab and the Milton Friedman Distinguished Service Professor in Economics at the University of Chicago, said the report allows decision-makers to see ‘exactly where emergency actions can be taken now’ to save tens of thousands of lives in the coming months.

Co-author Tamma Carleton, the Lab’s faculty head of research and an assistant professor at the University of California, Berkeley, said that better-targeted emergency efforts can save many lives this year, but that resources must also be mobilised now to design, deploy and evaluate the planning tools that will save lives in the years ahead.

The Lab argues that targeted action could avoid tens of thousands of deaths. It points to early-warning systems and heat action plans, cooling centres, protections for outdoor workers, expanded health-system capacity, more accurate temperature forecasting and wider access to cooling technologies, while noting that many of these measures have been evaluated only in specific geographies.

As climate change raises the frequency and intensity of extreme heat in many regions, the ability to measure its human cost will matter more.

The question is no longer only how hot India is becoming. It is also whether the country’s data systems can tell us how many lives that heat is costing.

Delhi has had a taste of cooler weather earlier than usual. On Sunday, the capital recorded a minimum temperature of 21°C at Safdarjung, its lowest September minimum in 18 years. Conversations to tackle winter pollution are also surfacing along with it. Rain and northerly winds kept the air relatively clean too, with the 4 pm AQI at 53.

But that clean-air window may not last. As the southwest monsoon retreats and winter approaches, Delhi is entering the season when pollution can begin to linger in the air for longer. The government is already preparing for it.

On Monday, Union Environment Minister Bhupender Yadav met Delhi Chief Minister Rekha Gupta and senior officials to review preparations for the winter pollution season. The measures include restrictions on older vehicles entering Delhi, “No PUCC, No Fuel” checks, higher parking charges, staggered office timings and work-from-home arrangements. Construction and demolition will also face tighter restrictions during the winter months.

Air Stops Moving

Delhi’s winter pollution is not simply a result of colder temperatures. The problem begins when cold weather changes how the atmosphere behaves. During winter, winds can become weaker and the layer of air in which pollutants normally mix can become shallower. Pollution from vehicles, industries, construction and other sources then has less space to disperse.

A temperature inversion can make this worse. Cold air stays close to the ground while warmer air sits above it, forming a kind of lid that prevents pollutants from rising and spreading. For people on the ground, the result is familiar: hazier skies, poorer visibility and air that can remain polluted for days.

What Changes After Monsoon

The monsoon gives Delhi some natural help in clearing the air. Rain removes particles from the atmosphere, while stronger winds help disperse emissions. Once the rains withdraw, that help diminishes. If winds are weak and the atmosphere becomes stagnant, pollution can begin to build up.

And Delhi does not produce all of that pollution on its own. Emissions from traffic, industries, construction, road dust and waste burning within the city mix with pollution transported from neighbouring areas. Agricultural fires in northern India can add to the particulate load during parts of the post-monsoon season.

Why the Recent Cold Matters

In December 2025, falling temperatures, dense fog and shallow atmospheric mixing accompanied a deterioration in air quality. On December 18, the maximum temperature was 20.1°C while the city’s 24-hour AQI reached 373.

That is why winter pollution is partly a weather story and partly an emissions story. As winter sets in, the amount of pollution released by the city and surrounding region matters. So does what happens to that pollution once it enters the atmosphere.