Temperatures across parts of continent around 10-15C above average for this time of year, while thunderstorms strike eastern Australia
Europe has experienced an exceptional heatwave this week, with temperature records broken across multiple countries under a persistent area of high pressure, commonly referred to as a “heat dome.” The UK surpassed its May maximum temperature record on Tuesday, with 35.1C recorded at Kew Gardens, London.
This broke the record set only the day before, with 34.8C recorded in London on Monday. Previously, the maximum May temperature record was 32.8C, recorded in 1922 and then matched in 1944. Ireland also broke its May maximum temperature, with 28.8C recorded at two weather stations – in Killarney in the south-west and Clonmel in the south.
India and Pakistan are no strangers to heat. This time of year is the worst, as heat peaks before the monsoon brings cooler conditions from June.
But this year’s heat is something else. Intense, sustained heat began in mid-April. Daily maximum temperatures have topped 46°C in many locations, with some areas running around 5–8°C above seasonal norms.
The unrelenting heat has driven record demand for electricity in India as people turn on air conditioners – and worsened drought conditions affecting more than a million square kilometres across both countries.
When extreme heat combines with humidity, it can be lethal. Human bodies cannot cool themselves easily in these conditions. The heatwave has claimed at least 37 lives in India and 10 in Pakistan. These figures are likely to be a major underestimate, as heat-related deaths are systemically undercounted in India.
Why is it so hot?
It’s usually a hot wait for the monsoon. But several factors can line up to make a bad season much worse.
One reason it’s been so bad this year is due to persistent high-pressure weather systems. When these systems sit in place, they make heatwaves more likely by suppressing cloud formation and reducing the chance of cooling rain. This year, strong high-pressure systems have lingered over parts of India and Pakistan, trapping hot air near the surface and allowing temperatures to build over many days.
With less rain, there’s more heat at ground level and soils dry out. Drier soils make things worse, because less heat is used up evaporating moisture in the soil and more goes into heating the land. High pressure systems can often hang around for many days, allowing extreme heat to build up.
It’s often worst in cities, as concrete and asphalt absorb heat during the day and release it slowly overnight. This means cities stay hotter overnight, boosting health risks for people without access to cooling.
Behind these immediate reasons is the big one: climate change. As the world gets steadily hotter, heatwaves get worse and worse. Estimates from World Weather Attribution suggest the first big heatwave from 15–29 April 2026 was made about three times more likely and about 1°C hotter due to climate change.
At current global levels of global warming (~1.4°C), this means the subcontinent faces similar events about once every five years. At present, we’re tracking towards 2.6°C of warming by 2100. At that level of heat, heatwaves like this would hit every 2-3 years and be 2.2°C hotter.
Humidity makes heat much more lethal
The number on a thermometer is only part of the danger.
Many parts of India and Pakistan are intensely humid. When sustained extreme heat arrives, humidity acts to intensify the threat to health. Humidity levels are worsening in parts of the region.
That’s because it’s harder to cool down naturally in humid conditions. Human bodies use sweating as the main method of cooling. When these beads of warm water evaporate off the skin, heat is carried away.
Humid air makes sweating a much less effective method of cooling. When the air already holds a lot of moisture, it takes longer for sweat to evaporate. The body can keep getting hotter even as it sweats.
This is why scientists are increasingly concerned about lethal humidity – when heat and humidity combine to rapidly sicken or kill.
Dying like this is deeply unpleasant. It begins with the core body temperature rising. People sweat more to try to shed the heat, but sweating doesn’t work well. If there’s no reprieve, the body temperature can keeps rising past 40°C and heatstroke can set in, damaging the brain and other vital organs. This can be fatal without rapid cooling and urgent care.
To gauge the combined danger of heat and humidity, scientists use measures such as the wet-bulb temperature. This reflects how much cooling is possible through sweating.
It used to be thought the limit for human survival was a wet-bulb temperature of 35°C. But new research shows heat and humidity can be lethal across a range of temperature and humidity combinations. For example, for older people who are outdoors, 35°C and 90% humidity is as deadly as 45°C and 30% humidity. These levels have already been reached during heatwaves in Southern Asia in recent years. For instance, even healthy 18-35 year olds are at risk of dying with humidity of 40% and temperatures of 45°C.
It’s likely some areas of the subcontinent have hit those limits at times during this intense period of heat. But we can’t say for sure, as most weather bulletins give air temperatures rather than wet-bulb temperature.
A threat faced unequally
The risks of heat and humidity are not faced equally. Wealthier people can turn on the air conditioner and avoid going outdoors.
But poorer people in informal settlements can’t escape the heat. Neither can construction workers, farmers, delivery riders and others doing physically demanding work outdoors.
There’s another risk too. The body needs cooler temperatures overnight to recover from intense heat. When the heat continues overnight, there’s no relief.
While cities are hotter than the surrounding areas, rural communities still face threats from heat and humidity. That’s because more work tends to be outdoors, healthcare is often far away and cooling is limited.
When could relief come?
When the monsoon arrives, it usually brings cooler conditions. Cloud cover and widespread rainfall help lower daytime temperatures, though humidity often stays high. The monsoon usually arrives in early June in southern India and covers the whole country by mid-July. In Pakistan, the monsoon typically arrives later, usually beginning in early July. The monsoon often lasts till September.
Relief can’t come too soon for the region.
Unfortunately, it won’t be the last threat. But as climate change ramps up, extreme heat and humidity will hit these nations more often – and more severely.
Oluwafemi E. Adeyeri receives funding from the Australian Research Council.
Sarah Perkins-Kirkpatrick receives funding from the Australian Research Council and is President of the Australian Meteorological and Oceanographic Society.
The NT government is arguing its planned mega Middle Arm gas industry precinct will be needed to help shore up Australia’s future fuel and energy supplies — but it has just identified that a tiny endangered herb could be growing in the way.
The government’s recent announcement of support for voluntary carbon and nature markets effectively offers a “warrant of fitness” to signal which markets can be trusted, without directly regulating them.
The aim is straightforward. By giving investors, landowners and developers confidence, the government hopes to unlock private finance for projects that reduce emissions or restore ecosystems.
As Associate Minister for the Environment Andrew Hoggard put it:
The pressures on nature and climate are bigger than the public purse.
But voluntary markets are based on self-imposed targets and governed by a patchwork of organisations. The credibility of climate claims in voluntary carbon markets has already been repeatedly challenged internationally.
This raises the deeper question of whether the government can create a credible framework by relying on externally developed standards in a lightly regulated system, or whether it risks outsourcing key decisions about environmental integrity.
How voluntary markets work
Carbon markets allow organisations to buy and sell “credits” representing reductions or removals of greenhouse gas emissions. In compliance markets – such as New Zealand’s Emissions Trading Scheme – participation is required by law, and governments set the rules.
Voluntary carbon markets are different. In these markets, businesses and individuals choose to buy credits to meet self-imposed climate targets or demonstrate environmental responsibility.
They are not governed by a single regulator. Instead, various independent organisations verify projects and issue credits, often following standards set by international bodies.
Voluntary nature markets work in a similar way but extend beyond carbon, covering biodiversity, water quality and ecosystem restoration.
This decentralised structure is both a strength and a weakness. It allows innovation and experimentation, but it also means that credibility depends heavily on the quality and consistency of external standards.
The credibility problem
Voluntary markets can channel finance into projects that fall outside regulated systems such as emissions trading schemes. But internationally, they have been dogged by controversy.
The main issue is credibility. For a carbon credit to have real climate value, the emissions reductions it represents must be real, additional and permanent. In practice, many credits fall short of these criteria.
Concerns have been documented widely. They include weak or inconsistent standards, limited transparency, difficulties verifying whether projects would have happened anyway, risks that stored carbon may later be released, and the possibility of the same reductions being counted more than once.
These problems are not just technical. Some analyses suggest a significant share of offsets used by companies may not deliver genuine emissions reductions.
Even where credits are of high quality, they can be misused to justify claims of “carbon neutrality” without any meaningful reduction in the use of fossil fuels.
The result has been a persistent gap between the promise of voluntary markets and their performance. Investor confidence has been shaken and concerns about greenwashing have grown.
A ‘light-touch’ solution
The government’s response is not to regulate the market directly, but to endorse schemes it considers credible.
However, endorsement does not eliminate the underlying risks.
These initiatives operate within a system that remains fragmented and evolving. Their effectiveness depends on how consistently standards are applied, how rigorously projects are assessed and how transparently information is shared.
By relying on these schemes, New Zealand is effectively tying its approach to international governance processes over which it has limited control. Endorsement may signal quality, but it also outsources key judgements about environmental integrity.
It is a light-touch approach in a context where the risks are already well established.
Beyond trees
Despite these concerns, voluntary markets could offer important opportunities, particularly for diversifying New Zealand’s approach to carbon removal.
At present, tree planting dominates the country’s removal strategy. But there is growing interest in alternatives such as wetland and peatland restoration, soil carbon, coastal “blue carbon” ecosystems and emerging technologies such as direct air capture.
Many of these approaches are not yet supported by compliance markets. Voluntary markets could provide early-stage funding, helping promising ideas get off the ground.
In this sense, a light-touch approach may encourage innovation.
But here, too, the risks are not insignificant. Measuring and verifying carbon removals in soils, oceans or engineered systems is often more complex and uncertain than measuring emissions reductions. This makes these areas especially vulnerable to weak standards and low-quality credits.
The same flexibility that enables innovation also increases the risk of poor environmental outcomes, particularly in areas where robust measurement is hardest.
What role should voluntary markets play?
The international evidence suggests voluntary carbon and nature markets can play a useful but limited role in climate policy.
They can help mobilise private finance, support conservation and restoration projects and provide early funding for emerging technologies. But they are not a substitute for direct emissions reductions or strong domestic regulation.
For New Zealand, this implies a need for clear boundaries. Voluntary markets should complement, not undermine, the emissions trading scheme and other core climate policies. That means ensuring strict rules around how credits can be used and what claims can be made.
Without guardrails, voluntary markets could expand faster than the governance needed to ensure they deliver genuine climate benefits.
The government’s strategy may succeed in attracting investment. But its long-term credibility will depend on whether that investment translates into real, measurable and lasting environmental gains.
Jennifer Campion received funding from the Ministry of Business, Innovation and Employment under the Endeavour Fund.
