As global temperatures rise, vast swathes of the global population are experiencing heat extremes that they have never faced before.
In some parts of the world, exposure to extreme heat is breaching survival limits for even the healthiest people. Heat-related deaths have increased rapidly in recent decades.
But the risks of extreme heat are even more acute for certain groups of people. Those most vulnerable include newborns, infants and children, those with preexisting medical conditions, including certain disabilities, the over 65s and workers who work outside or in a high heat indoor setting.
Despite these risks, our new research – published in the International Journal of Biometeorology – shows that vulnerable groups are being overlooked in studies of heat stress.
For early warning systems to be effective during heat extremes, it is crucial that appropriate thresholds are established for those most at risk.
Heat stress metrics
Heat stress is the build-up of body heat generated either internally by muscle use or externally by the environment. Research shows that the risks and impacts of heat stress are rising as the global climate warms.
Certain groups are typically more vulnerable to heat stress either because they are more exposed to heat – such as outdoor workers – or they have a physical limit in their ability to thermoregulate – that is, cool their body down – such as the elderly and young children.
A key metric to quantify heat stress is “wet-bulb globe temperature”. It has a long history as an international standard – originally developed by the US navy in the 1950s to indicate safe heat levels for military training.
Wet-bulb globe temperature has three components:
- Wet-bulb temperature, a measure of temperature that takes humidity and wind into account.
- Globe temperature, a measure of heat stress from direct sunlight.
- Air temperature.
Together, these components indicate a likelihood of an individual experiencing heat stress when specific thresholds are met.
Vulnerable groups overlooked
In our paper, we assess 931 peer-reviewed studies that use wet-bulb globe temperature to investigate heat stress thresholds for different population groups.
We find that the body of literature on wet-bulb globe temperature has grown substantially since the first study was published in December 1957.
The charts below show how those studies are divided by decade and sex (left) and by age group (right).
Of those 931 papers, 257 explored the differences due to sex and the majority focused on males (154).
This highlights a sex-related bias; however, this can somewhat be explained by the split in occupations where, traditionally, males end up in jobs that have clearer links to extreme heat exposure.
Only three of the 257 papers studied pregnant women and only one assessed other aspects of female health.
This is despite pregnant and postpartum women being a particularly vulnerable group. Experts in medicine, human thermal physiology and climate science have found a strong connection between extreme heat exposure and a range of negative birth outcomes, including preterm birth, low birth weight, cognitive deficits and even stillbirth.
Where the effects of age were considered (in 556 papers), most studies were conducted on adults (443) of 25-55 years of age and younger adults of 18-25 (48).
Very few studies focused on children, with five considering children of between one and five years old, just one focused on newborns up to 28 days old, and no studies of babies between one month and one year old.
For older adults, only three studies considered those 55-65 years old and four of those 65 and above. No studies placed an exclusive focus on elderly and/or older females, although women have a longer life expectancy than men.
Appropriate thresholds
In order to build a successful early warning system for extreme heat, it is necessary to identify appropriate thresholds for when people are at risk. Timely warnings can then help protect vulnerable groups by giving them time to take action.
In 2022, several UN agencies launched an “early warnings for all” initiative. This included a target to ensure that everyone in the world is protected by early warning systems for four types of extreme weather event – including heatwaves – by 2027.
However, there are many barriers to making sure that such a system is effective and properly supported by other policy measures.
One is that the wet-bulb globe temperature threshold proposed by the international standard organisation (specifically, ISO 7243:2017) only allows for different thresholds based on acclimatisation – that is, how much a person is used to their environment.
It takes a healthy individual around two weeks to acclimatise to a new thermal environment and those who are athletic often have a higher heat tolerance. (Although limits do exist, in a similar way to low oxygen at high altitudes.)
As we have described above, there has been a lot of research into appropriate thresholds for different groups of people. However, much of this understanding comes from studies on athletics.
In addition, as we have shown above, vulnerable groups are chronically underrepresented across these studies.
This is illustrated by the charts below, which show the heat thresholds estimated by the studies we have reviewed according to sex (top-left), age (top-right), clothing (bottom-left) and acclimatisation (bottom-right). Each dot represents a heat threshold estimate and the boxes and whiskers indicate the range across all the results.
The charts highlight how more research into thresholds is needed for vulnerable groups, particularly children, the elderly and older adults. For example, research in Europe has shown that elderly women are more likely to die during a heatwave.
When assessing the reception and response to extreme heat warnings, the perceived threat of danger is the strongest factor in why people do or do not heed them. This means it is even more important to fully understand which groups are most at risk.
By tailoring early warning systems to individuals needs and requirements, effective warnings can promote societal resilience by protecting the most exposed and vulnerable. And targeted heat thresholds are fundamental to this.
The post Guest post: Heat stress thresholds are not designed for vulnerable groups appeared first on Carbon Brief.
Guest post: Heat stress thresholds are not designed for vulnerable groups
Amira Odeh Quiñones is a hydrologist and Caribbean organiser for the 350.org climate campaign group
El Niño, likely to be one of the strongest in modern history, has arrived on Caribbean shores.
Drought is slowly creeping up on our islands. But unlike the fiery wildfires ravaging parts of Europe, there’s no smoke signalling the damage being done, no sirens to warn of the danger. Only announcements from public health officials to stay indoors and remain hydrated — as if outdoor workers and farming communities have the luxury to heed such advice.
During El Niño, strong atmospheric winds alter rain patterns and trap heat across the Caribbean. But while we have experienced El Niño many times before, it has become very visible in recent years how climate change is making this natural phenomenon worse.
Across the Greater Antilles, temperatures are soaring past 38°C (100°F), with real-feel indexes reaching a gruelling 43°C in parts of Puerto Rico where I live. Cuba has it worse. Widespread power outages mean that methods for cooling down are unavailable for most of the day, leaving millions of vulnerable people at risk of heat stroke when temperatures hit 38°C.
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During the last strong drought a decade ago, I had water only two days a week in my home. Today, there are many families whose taps are about to run completely dry. Water authorities have already begun strict rationing in some municipalities, with more on the list scheduled for rationing if conditions don’t change.
Water rationing is far more than an inconvenience; it is an immediate health risk. This means thousands of people need to constantly haul heavy buckets up flights of stairs just so they could bathe, cook, stay hydrated – the basics of survival.
Heat causes health problems
Puerto Rico is home to roughly 300,000 elderly residents. Many live alone, isolated and without support. They risk severe physical injury when carrying heavy water containers, and are wont to suffer from silent heat exhaustion in unventilated rooms.
Furthermore, when water shortages force residents to store water in open household containers, it inadvertently creates breeding grounds for Aedes aegypti mosquitoes. Paired with scorching temperatures that tend to shorten the mosquito breeding cycle, the region is facing explosive outbreaks of dengue fever that endanger our most vulnerable: children and the elderly.
The economic fallout is equally devastating. Dry fields mean millions of dollars in lost crops, forcing small agricultural businesses to collapse, needing urgent government relief to survive. Extreme fuel shortages have already paralyzed Cuba’s agricultural sector, cutting food output by 60% – the El Niño dry spell threatens to decimate it.
At sea, warmer ocean waters fuel massive influxes of sargassum seaweed. Rotting sargassum chokes our beaches, destroying the local tourism industry that so many working families rely on. Tangled seaweed also damages nets and boat engines, slashing fish catches and driving up equipment costs for local fishers.
In the south of Puerto Rico, the coastal town of La Parguera is currently witnessing a historic amount of sargassum on its shores. This has halted most of the boating activity in the area, which is the seaside town’s main tourist draw and economic driver.
All over the Caribbean, from town halls to local group gatherings, the story I hear is always the same: constant headaches, lost work hours, failing health, and a sense that quality of life is silently being stolen. The compounding effects of heatwaves, drought, and marine destruction are exhausting our people, our islands.
Climate change to blame
Climate change makes each El Niño year hotter and more damaging. Higher baseline global temperatures increase the energy and moisture available for extreme weather. Latest projections show that El Niño may push the monthly global average temperature past 2°C of warming for the first time in early 2027. In the Caribbean islands, that will not just be breaking records – it’ll be breaking lives.
Recently, I had the opportunity to share a panel with climate scientists behind what is known as the field of “attribution science” – or the science that compares today’s climate conditions to what the Earth’s climate would be like without human activity, particularly burning fossil fuels. They’re unequivocal: it’s no longer a question of whether extreme weather is caused by climate change, it’s just a question of how much.
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Attribution science recently got a boost from the U.S.’ top scientific advisory body. The National Academies of Sciences, Engineering and Medicine recognized that researchers’ methods have advanced considerably in recent years, resulting in better assessments on how much extreme weather can be attributed to human-caused climate change. It noted that attribution findings could be relevant in some types of legal cases, including those seeking damages from oil companies for climate impacts.
This crisis, which is already taking a heavy toll on our communities’ survival, needs real, urgent, and structural action that goes beyond aid. With similar droughts now gripping parts of Asia and Africa, we’re falling into the familiar narrative of treating the looming humanitarian crisis as if no one was to blame, as if it is being caused solely by a natural phenomenon we can’t control.
It’s not. The world was already on fire before its regular visitor, El Niño, came. While we need humanitarian action, we need climate action too, in order to permanently put out the flames.
The post When taps run dry in the Caribbean, it’s not enough to blame El Niño appeared first on Climate Home News.
When taps run dry in the Caribbean, it’s not enough to blame El Niño
China has released a five-year plan dedicated to addressing climate change.
The 15th five-year plan for a national response to climate change is the latest in a series to outline in-depth climate and energy targets for the 2026-2030 period.
These include five-year plans for “building a Beautiful China”, developing a “new-type energy system” and developing renewable energy.
There are also separate “action plans” for the 2026-2030 period, such as for peaking carbon emissions.
China has pledged to peak its emissions before 2030 and reach carbon neutrality before 2060.
The new plan does not include any major new targets, instead consolidating and reaffirming existing policies.
Nevertheless, it includes significant signals on key policy areas, such as non-carbon dioxide (CO2) greenhouse gases, global climate governance and carbon markets.
Below, Carbon Brief examines some of the notable elements in the latest five-year plan and what it reveals about China’s policy direction through to 2030.
What does the climate plan cover?
The Ministry of Ecology and Environment (MEE) released the plan in late July, in unison with 18 other government departments. These include the National Development and Reform Commission (NDRC), China’s top economic planning agency, and the National Energy Administration.
The document covers a range of topics, including CO2 emissions, other greenhouse gases (non-CO2 GHGs), carbon markets, carbon footprints, climate adaptation and international cooperation on climate change.
For the first time at the five-year plan level, the plan creates a comprehensive target system covering all areas of climate policy, say officials in a MEE Q&A.
They describe it as “the main policy instrument” for advancing China’s climate action during 2026-2030.
China rarely issues high-level multi-year policies dedicated to “responding to climate change”. In 2014, the NDRC published a plan on the topic running through to 2020, but this was not linked to a five-year plan period.
Qin Yan, principal analyst at ClearBlue Markets, tells Carbon Brief that the plan shows that China’s climate governance has reached “an unprecedented strategic level”.
She adds that the plan creates an “all-encompassing target system” to support China’s Paris Agreement climate pledges for 2030 and 2035.
In its 2030 pledge, China aimed to peak emissions “before 2030” and reduce carbon intensity – its emissions per unit of GDP – by more than 65% from 2005 levels.
Last year, president Xi Jinping personally announced China’s 2035 pledge to cut China’s greenhouse gas emissions to 7-10% below peak levels by 2035, while “striving to do better”.
The five-year plan marks a new phase in China’s climate policy, according to researchers at CIB Research, an economic research body affiliated with the Industrial Bank, whose largest shareholder is the Fujian provincial government.
Their analysis adds that the plan represents a broad effort to strengthen China’s climate-governance system, implementation mechanisms and underlying capacity.
Nevertheless, several headline targets and policies in the document simply reiterate already established plans.
These include:
- Cutting carbon intensity by 17% across the five years
- Reducing carbon intensity per product in industries under China’s carbon market by 3%
- Substituting fossil fuels with renewables
- Strengthening climate adaptation
- Supporting the “free flow” of cleantech
What does the plan say about non-CO2 GHGs?
The plan also goes into detail on China’s approach to non-CO2 GHGs. This includes reaffirming a target of an emissions “reduction capacity” from these gases totalling 30m tonnes of CO2 equivalent (MtCO2e) by 2030, although the baseline is unclear.
The target previously appeared in the overarching five-year plan, as well as the plan for building a “Beautiful China”.
The goal refers to emissions reductions, which can be realised through implementing current non-CO2 emissions reduction policies and projects, says Chen Meian, programme director and senior analyst at the Institute for Global Decarbonization Progress (iGDP).
She adds that it is “relatively achievable”, with sources including increasing the number of coal-mine methane utilisation projects.
She points to an MEE explanatory note for a draft methodology under the China Certified Emission Reduction (CCER) scheme, China’s voluntary carbon-credit market. Chen says the note suggests that projects using ventilation air methane and coal-mine methane with concentrations below 8% alone could deliver around 20MtCO2e of reduction by 2030.
The note states that, currently, such projects are estimated to be able to “generate annual emission reductions of approximately 4.5MtCO2e”.
In addition, Chen says, measures targeting industrial nitrous oxide (N2O) and hydrofluorocarbons (HFCs) could help make up the remainder needed to meet the target.
According to iGDP analysis of biennial reports submitted by China to the UNFCCC, China emitted around 14,000MtCO2e of GHGs in 2021, excluding land use, land-use change and forestry (LULUCF).
Non-CO2 GHGs accounted for around 2,700MtCO2e, or 19%, of the total, the majority of which was methane, as shown in the figure below.
China’s plans to curb these super-pollutants in the five-year period include coal-mine methane utilisation projects, end-of-pipe destruction technologies for HFCs and guidance on the use of catalysts to reduce N2O emissions.
The plan also calls for the recovery and replacement of sulphur hexafluoride (SF6) in power equipment.
For Chen, the plan’s focus on SF6 control is particularly noteworthy. She says the gas is “finally receiving policy attention” and that proactive action is “timely and will help avoid future emissions growth” as China’s power system expands.
What does the plan say about global climate governance?
One of the plan’s clearest objectives for international cooperation is for China to play a more active role in global climate governance.
By 2030, it says China should markedly increase its “influence, guiding power, shaping power and moral appeal” in this area.
It says China’s climate action could also feed into the Global Governance Initiative, a policy initiative aimed at reforming the global governance system.
China will also aim to “build a new narrative on climate governance”, it adds.
Prof Thomas Hale, a professor in public policy at the University of Oxford’s Blavatnik School of Government, writes on LinkedIn that the plan “marks a major rhetorical shift” towards China being increasingly willing to “lead and shape” global climate action.
Another clear focal point for international cooperation is in carbon markets.
The plan calls for China to expand the global influence of its carbon market, such as through international rule-setting, cooperation on standards and by hosting the China Carbon Market Conference.
Qin says China’s more active role in global carbon pricing is already evident in the launch of the open coalition on compliance carbon markets with the EU and Brazil. This coalition is expected to adopt a work plan at the China Carbon Market Conference in September.
Qin also notes that China “could become the world’s largest [carbon] offset buyer” as its energy transition progresses.
The country would, therefore, “benefit from helping shape global rules under the Article 6 framework [for carbon trading under the Paris Agreement]”, she adds.
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The post Q&A: What is in China’s new five-year plan for climate change? appeared first on Carbon Brief.
Q&A: What is in China’s new five-year plan for climate change?
About a quarter of the countries signed up to the Paris Agreement are still breaching its rules by failing to submit a new national climate plan, 18 months after the February 2025 deadline.
Forty-five nations had not submitted a plan known as a nationally determined contribution (NDC), according to the Paris Agreement Implementation and Compliance Committee’s (PAICC) newly-published report of its 7-10 July 2026 meeting. One, Oman, has published it since the meeting.
Twelve countries ignored the committee’s repeated attempts to find out why they had not yet produced a climate plan, the report said. They will be invited to the committee’s next meeting, from September 1-4, so it can identify the challenges and constraints they face.
Members of the committee are divided, as they were at their last meeting, on whether to name those countries publicly and will debate the question again in September.
The PAICC does not have any power to punish governments, as building these powers into the Paris Agreement was thought to be so controversial that it could have stopped some governments from joining, experts have previously told Climate Home News.
A key requirement of the landmark 2015 Paris Agreement is that governments publish a more ambitious NDC every five years, setting targets to reduce their planet-heating emissions and outlining their policies to adapt to climate change, in order to meet the accord’s goals on limiting global warming and protecting people from its effects.
The latest set – the third round of plans, with new targets for 2035 – was due in 2025.
Some medium-sized emitters
Countries without an updated NDC include Egypt, Vietnam, Argentina and the Phillippines, all of which rank among the world’s 40 largest greenhouse gas emitters. The rest of the countries are smaller, poorer nations, with many in Africa or the Caribbean.
Some nations have argued that they cannot put together an NDC – which requires a significant amount of work in tracking emissions and consulting on how to curb them across the economy – because of exceptional circumstances. For example, a letter from a Sudanese official to the PAICC committee, seen by Climate Home News, says that the country’s civil war has led to the suspension of its NDC preparation.
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The US and Iran are not signed up to the Paris Agreement, although the US submitted a 2035 NDC under the Biden administration before Donald Trump pulled the US out of the UN climate accords.
The committee also expressed concern that the UN’s NDC registry continued to label the climate plans of countries that are no longer party to the Paris Agreement as “active”, according to its report. The US submission has since been archived.
Since the last PAICC meeting in March, ten countries have published NDCs. The committee did not name them but they include India, Algeria, Cameroon and Guyana.
The post Quarter of countries still missing UN climate plans 18 months after deadline appeared first on Climate Home News.
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