Electric vehicles (EVs) now account for more than one-in-four car sales around the world, but the next phase is likely to depend on government action – not just technological change.
That is the conclusion of a new report from the Centre for Net Zero, the Rocky Mountain Institute and the University of Oxford’s Environmental Change Institute.
Our report shows that falling battery costs, expanding supply chains and targeted policy will continue to play important roles in shifting EVs into the mass market.
However, these are incremental changes and EV adoption could stall without efforts to ensure they are affordable to buy, to boost charging infrastructure and to integrate them into power grids.
Moreover, emerging tax and regulatory changes could actively discourage the shift to EVs, despite their benefits for carbon dioxide (CO2) emissions, air quality and running costs.
This article sets out the key findings of the new report, including a proposed policy framework that could keep the EV transition on track.
A global tipping point
Technology transformations are rarely linear, as small changes in cost, infrastructure or policy can lead to outsized progress – or equally large reversals.
The adoption of new technologies tends to follow a similar pathway, often described by an “S-curve”. This is divided into distinct phases, from early uptake, with rapid growth from very low levels, through to mass adoption and, ultimately, market saturation.
However, technologies that depend on infrastructure display powerful “path-dependency”, meaning decisions and processes made early within the rollout can lock in rapid growth, but equally, stagnation can also become entrenched, too.
EVs are now moving beyond the early-adopter phase and beginning to enter mass diffusion. There are nearly 60m on the road today, according to the International Energy Agency, up from just 1.2m a decade ago.
Technological shifts of this scale can unfold faster than expected. Early in the last century in the US, for example, millions of horses and mules virtually disappeared from roads in under three decades, as shown in the chart below left.
Yet the pace of these shifts is not fixed and depends on the underlying technology, economics, societal norms and the extent of government support for change. Faster or slower pathways for EV adoption are illustrated in the chart below right.
Internal combustion engine (ICE) vehicles did not prevail in becoming the dominant mode of transport through technical superiority alone. They were backed by massive public investment in roads, city planning, zoning and highway expansion funded by fuel taxes.
Meanwhile, they faced few penalties for pollution and externalities, benefitting from implicit subsidies over cleaner alternatives. Standardisation, industrial policy and wartime procurement further entrenched the ICE.
EVs are well-positioned to follow a faster trajectory, as they directly substitute ICE vehicles while being cleaner, cheaper and quieter to run.
Past transitions show that like-for-like replacements – such as black-and-white to colour TVs – tend to diffuse faster than entirely novel products.
Late adopters also benefit from cost reductions and established norms. For example, car ownership took 60 years to diffuse across the US, but just 20 years in parts of Latin America and Japan.
In today’s globalised economy, knowledge, capital and supply chains travel faster still. Our research suggests that the global EV shift could be achieved within decades, not half a century.
Yet without decisive policy, investment and coordination, feedback loops could slow, locking in fossil-fuel dependence.
Our research suggests that further supporting the widespread deployment of EVs hangs on three interlinked actions: supporting adoption; integrating with clean electricity systems; and ensuring sustainability across supply chains and new mobility systems.
Closing the cost gap
EVs have long offered lower running costs than ICE vehicles, but upfront costs – while now cost-competitive in China, parts of Europe and in growing second-hand markets – remain a major barrier to adoption in most regions.
While battery costs have fallen sharply – lithium-ion battery packs fell by 20% in 2024 alone – this has not fully translated into lower retail vehicle prices for consumers.
In China, a 30% fall in battery prices in 2024 translated into a 10% decline in electric SUV prices. However, in Germany, EV retail prices rose slightly in 2024 despite a 20% drop in battery costs.
These discrepancies reflect market structures rather than cost fundamentals. Our report suggests that a competitive EV market, supported by transparent pricing and a strong second-hand sector, can help unlock cost parity in more markets.
Beyond the sale of EVs, government policy around running costs, such as fuel duty, has the potential to disincentivse EV adoption.
For example, New Zealand’s introduction of road-pricing for EVs contributed to a collapse in registrations from nearly 19% of sales in December 2023 to around 4% in January 2024.
EV-specific fees have also been introduced in a number of US states. Last month, the UK also announced a per-mile charge for EVs – but not ICEs – from 2028.
Addressing the loss of fuel-duty revenue as EVs replace ICE vehicles is a headache for any government seeking to electrify mobility.
However, to avoid slowing diffusion, new revenues could be used to build out new charging infrastructure, just as road-building was funded as the ICE vehicle was scaling up.
While subsidies to support upfront costs can help enable EV adoption, the best approach to encouraging uptake is likely to shift once the sector moves into a phase of mass diffusion.
Targeted support, alongside innovative financing models to broaden access, from blended finance to pay-as-you-drive schemes, could play a greater role in ensuring lower-income drivers and second-hand buyers are not left behind.
Mandates as engines of scale
Zero-emission vehicle (ZEV) mandates and ICE phase-out deadlines can reduce costs more effectively than alternatives by guaranteeing market scale, our research finds, reducing uncertainty for automakers and pushing learning rates forward through faster production.
California’s ZEV mandate was one of the first in the 1990s, a policy that has since been adopted by ten other US states and the UK.
China’s NEV quota system has produced the world’s fastest-growing EV market, while, in Norway, clear targets and consistent incentives mean EVs now account for nearly all of new car sales. These “technology-forcing” policies have proved highly effective.
Analyses consistently show that the long-run societal benefits of sales mandates for EVs far outweigh their compliance costs.
For example, the UK’s ZEV mandate has an estimated social net present value of £39bn, according to the government, driven largely by emissions reductions and lower running costs for consumers.
Benefits can also extend beyond national borders. For example, California’s “advanced clean cars II” regulations – adopted by a number of US states and an influence on other countries – have been instrumental in compelling US automakers to develop and commercialise EVs, which can, in turn, trigger innovation and scale to reduce costs worldwide.
Research suggests that, where possible, combining mandates and incentives creates further synergies: mandates alleviate supply-side constraints, making subsidies more effective on the demand side.
Public charging: a critical bottleneck
Public charging is one of the most significant impediments to EV adoption today.
Whereas EVs charged at home are substantially cheaper to run than ICE vehicles, higher public charging costs can erase this benefit – in the UK, this can be up to times the home equivalent.
While most homes in the UK, for example, do have access to off-street parking, there are large swathes of low-income and urban households without access to private driveways. For these households, a lack of cheap public charging has been described as a de facto “pavement tax”, which is disincentivising EV adoption and resulting in an inequitable transition.
Our research shows that a dual-track charging strategy could help resolve the situation. Expanding access to private charging – through cross-pavement cabling, “right-to-charge” legislation for renters and planning mandates for new developments could be combined with strategic investment in public charging, to overcome the “chicken-and-egg” problem for investors uncertain about future EV demand.
Meanwhile, “smart charging” in public settings – where EV demand is matched with cheaper electricity supply – can also help close the affordability gap, by delivering cheap off-peak charging that is already available to those charging at home.
The Centre for Net Zero’s research shows that drivers respond to dynamic pricing outside of the convenience of their homes, which reduces EV running costs below those of petrol cars.
The figure below shows that, while the level of discount being offered had the strongest impact, lower-income areas showed the largest behavioural response, indicating that they may stand to gain the most from a rollout of such incentives.
Our research suggests that policymakers could encourage this type of commercial offering by creating electricity markets with strong price signals and mandating that these prices are transparent to consumers.
Integrating with clean electricity grids
Electrification is central to decarbonising the world’s economies, meaning that sufficient capacity on electricity networks is becoming a key focus.
For the rollout of EVs, pressure will be felt most on low-voltage “distribution” networks, where charging is dispersed and tends to follow existing peaks and troughs in domestic demand.
Rather than responding to this challenge by just building out the grid – with the corresponding economic and political implications – making smart charging the norm could help mitigate pressure on the network.
Evidence from the Centre for Net Zero’s trials shows that AI-managed charging can shift EV demand off-peak, reducing residential peak load by 42%, as shown in the chart below.
Additionally, the amount of time when EVs are plugged in but not moving is often substantial, giving networks hours each day in which they can shift charging, targeting periods of low demand or high renewable output.
The system value of this flexible charging is significant. In the UK, managed charging could absorb 15 terrawatt hours (TWh) of renewable electricity that would otherwise be curtailed by 2030 – equivalent to Slovenia’s entire annual consumption.
For these benefits to be realised, our research suggests that global policymakers may need to mandate interoperability across vehicles, chargers and platforms, introduce dynamic network charges that reflect local grid stress and support AI-enabled automation.
Bi-directional charging – which allows EVs to export electricity to the grid, becoming decentralised, mobile storage units – remains underexploited. This could allow EVs to contribute to the capacity of the grid, helping with frequency and providing voltage support at both local and system levels.
The nascency of such vehicle-to-grid (V2G) technology means that penetration is currently limited, but there are some markets that are further ahead.
For example, Utrecht is an early leader in real-world V2G deployment in a context of significant grid congestion, while Japan is exploring the use of V2G for system resilience, providing backup power during outages. China is also exploring V2G systems.
Our research shows that if just 25% of vehicles across six major European nations had V2G functionality, then the theoretical total capacity of the connected vehicles would exceed each of those country’s fossil-fuel power fleet.
Mandating V2G readiness at new chargepoints, aligning the value of exports with the value to the system and allowing aggregators to pool capacity from multiple EVs, could all help take V2G from theory to reality.
A sustainable EV system
It is important to note that electrification alone does not guarantee sustainability.
According to Rocky Mountain Institute (RMI) analysis, the total weight of ore needed to electrify the world’s road transport system is around 1,410mtonnes (Mt). This is 40% less than the 2,150Mt of oil extracted every year to fuel a combustion-based system. EVs concentrate resource use upfront, rather than locking in fossil-fuel extraction.
Moreover, several strategies can reduce reliance on virgin minerals, including recycling, new chemistries and improved efficiency.
Recycling, in particular, is progressing rapidly. Some 90% of lithium-ion batteries could now be recycled in some regions, according to RMI research. Under an accelerated scenario, nearly all demand could be met through recycling before 2050.
Finally, while our report focuses largely on EVs, it is important to highlight that they are not a “silver bullet” for decarbonising mobility.
Cities such as Seoul and New York have demonstrated that micromobility, public transport and street redesign can cut congestion, improve health and reduce the number of overall vehicles required.
Better system design reduces mineral demand, lowers network strain and broadens access.
The ‘decision decade’ ahead
Policy decisions made today will determine whether EVs accelerate into exponential growth or stall.
Our research suggests that governments intent on capturing the economic and environmental dividends of electrified mobility are likely to need coherent, cross-cutting policy frameworks that push the market up the steep climb of the EV S-curve.
The post Guest post: How to steer EVs towards the road of ‘mass adoption’ appeared first on Carbon Brief.
Guest post: How to steer EVs towards the road of ‘mass adoption’
The African continent’s hopes for a legally binding agreement to combat drought have been dashed again, as UN land restoration talks in Mongolia passed the issue onto the next set of talks in Egypt in two years’ time.
For over a decade, Africa has pushed for a UN protocol on drought risk management that would acknowledge drought as an issue requiring a regional and global – not just a national – response, potentially paving the way for more finance to help ensure water is available when drought hits.
A formal protocol would enable countries to transition from reacting to drought once it hits to “a proactive enabling mechanism to address drought and its effects such as migration”, said a Tunisian negotiator on behalf of the African Group of countries last week. Once land is regularly too dry and infertile to grow crops or graze animals, people often leave to seek a living elsewhere.
But this effort to adopt a protocol, led by Africa, has been resisted at successive land restoration COPs under the UN Convention to Combat Desertification (UNCCD), mainly by developed countries, which argue that a legally weaker alternative – a framework – would be faster and cheaper to set up.
Governments at the previous COP in Saudi Arabia in 2024 failed to reach agreement despite talks running past midnight, while this year’s saw African officials coordinate a walkout from negotiating rooms on Wednesday morning, according to two sources at the talks.
Drought deal delayed until 2028
The IISD’s Earth Negotiations Bulletin, a non-governmental organisation which unlike the media is allowed to watch and report on closed-door talks, said a call to suspend negotiations on Wednesday showed negotiations had reached “boiling point” and “made some jaws drop”.
Negotiations resumed after a lunchtime meeting with the Mongolian COP presidency although governments were only eventually able to agree that they could not find consensus in Ulaanbaatar and should resume talks on an instrument to deal with drought in 2028.
Christine Colvin, WWF’s head of freshwater policy, told Climate Home News that, with droughts hitting from Honduras to the English region of Hampshire, something concrete – whether a protocol or a framework – is needed urgently “rather than the can being kicked down the road for another two years as will now happen with the protocol procrastination”.
But, in a closing press conference on Friday, the Mongolian minister presiding over talks celebrated that governments had reached consensus on several “contentious” issues and that agenda items blocked at this year’s COP17 would be put on the agenda for COP18 in Egypt.
US blocks agenda items
Other agenda items that divided countries were on measuring land degradation’s effects on women, enhancing the involvement of civil society and women in land COPs, and the UNCCD working more closely and effectively with the UN’s climate and nature conventions.
On the COP’s opening day two weeks ago, the US representative said the Trump government objects to these agenda items “on their premise and no amount of negotiation will allow us to join consensus on these items. As such we request that they be struck from the agenda at which time we will then be able to approve it, saving us valuable negotiating time.”
A US State Department spokesperson later told Climate Home News that the US wants the UN “to get back to basics by refocusing on its core mandate, eliminating overlap, and reducing competition for scarce resources”.
The spokesperson added, “that means prioritising the concrete work member states created [the UN] to do – rather than diverting limited time, attention, and resources toward social and political agendas, including gender-related initiatives.”
On COP’s first day, the European Union and Brazil pushed back against the blocking of these agenda items, with a Brazilian negotiator saying his country attaches “great importance” to them. But the Mongolian presidency directed governments to adopt the rest of the agenda without the controversial items, which were discussed privately with countries throughout the two weeks.
An EU statement, read out later by Irish minister Timmy Dooley, accused “some parties” (meaning national governments) of having adopted a “less constructive approach” and preventing “discussions on important matters from even commencing”.
The agenda items the US refused to engage with were never discussed and were only placed onto the agenda for the next COP on the last day. Those talks will take place in Egypt in two years’ time, with Donald Trump due then to be in his last year as US president.
No restoration without women
The blocking of the gender agenda item has stymied attempts, agreed on by governments at the last COP, to develop gender-specific indicators for the UNCCD’s next overall framework and to facilitate more women delegates at COPs. Women made up only about a quarter of delegates to COP15 in 2022, UNCCD analysis with the latest data shows
Criticising the move to keep gender off the agenda, the EU said in a statement that it welcomes “the attention being given at COP17 to women pastoralists and herders, recognising their contribution to sustainable land management and resilient rural livelihoods”.
The head of the UNCCD, former Egyptian environment minister Yasmine Fouad, said on Friday that “regardless that the agenda item was blocked”, she was proud that she and COP17 President Batmunkh Battsetseg had led the COP as women and attended the gender caucus (a meeting of groups supporting women at the talks).
“Without the women,” she told the closing press conference on Friday, “we will not be able to restore land, restore hope, restore life or restore even our children and grandchildren. And we will keep on pushing that agenda.”
The civil society agenda item aimed to allow NGOs to attend land COP negotiations, as they do at climate COPs, and included terms of reference for an Indigenous Peoples Caucus.
A representative of Indigenous Peoples told the COP’s closing plenary meeting that the group had “deep disappointment that the agenda of this COP has removed the dedicated space for indigenous peoples”. “We cannot restore the land while removing the voices of those who care for it,” she said.
On Tuesday, the UNCCD’s deputy head Andrea Meza was asked about Indigenous Peoples’ participation. She said that the blocking of “one agenda item” is “generating uncertainty in the progress” towards creating caucuses for Indigenous Peoples and for Local Communities within the talks.
Because of the “complex geopolitical situation” making it hard to obtain consensus, coalitions of the willing have become more important, she added.
Mining out, money in
Outside the formal negotiations, the summit was marked by a focus on the strongly Mongolian issues of the role played by pastoralists and rangelands like grasslands, as well as mining, in both degrading and restoring land.
Part of the conference was sponsored by Australian mining company Rio Tinto and its local partner Oyu Tolgoi. Their presence was protested by campaigners wearing T-shirts calling on the companies to “stop wasting drinking water” and to “get out of Mongolia”.
The UNCDD and others praised the success of the summit in raising more finance for land restoration. The COP saw institutions like the Asian Development Bank and Global Environment Facility pledge money to combat land degradation, with the UNCCD estimating that $645 million of new commitments were made.
An estimated $355 billion a year is needed through 2030 to meet global land restoration commitments, compared with around $77 billion currently invested. Private finance accounts for only around 6% of global investment, according to the UNCCD.
UNCCD chief scientist Baron Orr told a press conference that many of the announcements were public-private partnerships that use government money to “even the playing field” for companies that want to protect land, in a bid to ensure they are not disadvantaged compared with those that do not.
Such partnerships are a “huge opportunity”, he said, especially as “we’re not in a moment of public finance – public finance is tight in every country.”
The post Despite African walkout, fractious land COP ends without drought deal appeared first on Climate Home News.
Despite African walkout, fractious land COP ends without drought deal
Burdened by rising fuel import costs and an “ocean crisis” of record-breaking heat, Pacific island nations are seeking to build support for a new regional fund ahead of COP31, intended to channel investment into renewable energy, community resilience and ocean protection, experts said.
Leaders from the 18-member Pacific Islands Forum (PIF), including Australia and New Zealand, are expected to issue a call for global pledges to the Pacific Resilience Facility (PRF) at a high-level meeting this coming week in Palau, seeking to build a new model for financing climate action.
The new regional fund was formally launched in May this year and is meant to “serve communities at a community level”, swiftly channelling investments for their projects on the ground, according to Fiji’s assistant minister for foreign affairs, Lenora Qereqeretabua.
“We are expecting pledges for the PRF, and these funds will go to communities that apply,” she told journalists at an online briefing. “We have organised it in such a way that it makes our application processes much, much easier than applying for global funding.”
Qereqeretabua added that she expects that PRF funds will be “utilised by communities to protect themselves from climate change and the effects of climate change.”
The Pacific Islands Forum meeting is expected to shape the region’s priorities ahead of this year’s pre-COP, hosted by Fiji and Tuvalu, and COP31, which will be co-led by Australia and Türkiye.
At COP31, a dedicated session on the climate finance needs of small island states will seek to drive pledges into the PRF. The fund has so far received about $172 million in capital – with about $67 million coming from Australia – and aims to close the year with $500 million.
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Ocean heat and fossil fuel shocks
Leaders from the Pacific will meet in Palau from Sunday amid an “ocean crisis” of record-breaking ocean heat caused by this year’s “super El Niño”, according to Kevin Chand, Pacific ocean policy director at National Geographic’s Pristine Seas conservation project.
Leaders at the PIF are expected to put forward commitments towards new marine protected areas, which will be key for shielding ecosystems from future climate extremes, Chand said. The forum is expected to issue a statement on the need for ocean action at COP31, and announce commitments towards reaching the global goal of protecting 30% of the planet’s land and sea ecosystems by 2030.
Rising ocean heat could lead to food insecurity and lost government earnings in the region, as key fish stocks like tuna start migrating away from their coastline in search of colder waters, said Coral Pasisi, director of climate change and sustainability at the Pacific Community (SPC).
Climate shocks are deepening existing economic pressures, as Pacific nations have spent up to a quarter of their GDP on fossil fuel imports due to the war in Iran, according to a recent report by the University of New South Wales (UNSW) in Australia.
Wesley Morgan, one of the study’s authors, told journalists that partner nations “ought to be putting their money where their mouth is”, and should support the energy transition in the Pacific by covering the upfront costs of switching from polluting diesel to solar power, batteries and electricity grid upgrades.
China keeps Indonesia’s battery dream afloat but future less certain
Given the increase in climate-related shocks and sea-level rise, the PIF should also mention the need to phase out fossil fuel extraction and consumption, said Sindra Sharma, international policy lead at the Pacific Islands Climate Action Network (PICAN).
Last year’s COP30 failed to deliver a global roadmap on transitioning away from fossil fuels, which led to a group of countries – including several Pacific island nations – pursuing their own fossil fuel phase-out summit in Santa Marta, Colombia. Next year’s conference will be hosted by Tuvalu and co-chaired by Ireland, which should also receive backing from the PIF, Sharma said.
Both the chairs of the Santa Marta coalition and the Australian COP31 co-presidency have vowed to continue a push for this topic to be discussed at COP31.
New fund to test allies
As local communities in the Pacific struggle to access global climate funds, the PRF’s planned model for quick, direct disbursements has “very solid and good” intentions, Sharma said, but it will need political and financial backing from donor countries.
“The proof is going to be when the fund actually starts operating and delivering to communities,” she added. “If there is too much bureaucracy in being able to access the funds, for example. These things will have to be scrutinised.”
The facility aims to deliver funds in two categories: one for climate adaptation and “disaster resilience”, and another for social and community resilience that includes areas like community capacity-building, education, data analytics and financial management, among others. It will launch its first call for proposals at the PIF.
Morgan added that Australia will need to “leverage global interests” so that funding is directed to the Pacific Resilience Facility “or else the Pacific won’t be able to trust Australia as a partner”. The country ratified the PRF treaty in May, triggering its entry into force.
“The perception [of Australia] in the region is genuinely divided, and it’s worth being honest about it,” Sharma said, adding that the pre-COP31 in Fiji, which is usually limited to a technical space for negotiations, will determine how meaningful Australia’s advocacy for the Pacific can be.
This time, Pacific nations want to use the pre-COP in early October as an opportunity to demonstrate the challenges their largely low-lying islands face and to advocate for their political priorities, including a renewed global effort to limit global warming to 1.5C by cutting emissions faster and deeper. World leaders are due to visit Tuvalu to experience the frontline of rising sea levels, although Australia and Fiji have yet to confirm who will attend.
“In Bonn, Australia was largely missing on the negotiated outcomes that we so urgently need to see. It’s not enough to get Pacific priorities on the agenda. Agenda placement is not delivery,” Sharma added.
The post Pacific islands seek backing for new regional fund ahead of COP31 appeared first on Climate Home News.
Pacific islands seek backing for new regional fund ahead of COP31
Climate Change
Climate change exposes 580 million children to 20 extra ‘heat-stress days’ every year
More than 40% of children under the age of 10 globally are already experiencing at least 20 additional “heat-stress days” due to climate change.
This is according to a new attribution study, published in Science Advances, which combines climate models with demographic data to assess the age groups and regions that are exposed to the most hot, humid days.
The study finds that children up to the age of nine already face more additional heat-stress days globally as a result of climate change than any other age group.
It adds that south Asia and west Africa are recording the greatest childhood exposure to dangerous levels of humid heat – largely because these regions have a rapidly growing population with the highest proportion of young children.
As the climate warms, children will continue to be more exposed to heat stress than any other age group, the paper warns.
The lead author of the study tells Carbon Brief that the findings should inform discussions about climate justice, noting that children in developing countries “have contributed the least to historical greenhouse gas emissions”.
Humid heat
High temperatures can be deadly. For example, the heatwaves that swept across Europe in the summer of 2026 have been linked to tens of thousands of “excess deaths”.
A prominent 2021 study found that children born in the 21st century will be exposed to more extreme weather events in their lifetimes than their parents and grandparents.
Four years later, a study conducted by scientists from the same team found that more than half of children born in 2020 – around 62 million people – will experience “unprecedented lifetime exposure” to heatwaves, even if warming is limited to 1.5C.
Now, the latest research from the same team finds that children already face greater exposure to dangerous levels of humid heat than adults as a result of human-caused climate change.
Extreme heat is particularly dangerous when combined with high humidity. In hot weather, the human body produces sweat to cool itself down. However, as humidity increases, sweating becomes less effective.
The study uses wet-bulb globe temperature – a measure of temperature that takes humidity and wind into account – to calculate heat stress. It defines a “heat-stress day” as any day with a wet-bulb globe temperature above 28C, as this is considered the threshold for “moderate heat stress”
The authors then use climate models to simulate global temperature patterns in the present-day climate. (The authors use the climate of 2023, in which human activity has caused 1.3C of warming, to represent the “present-day”.)
They then count the number of heat-stress days that each country records on average, per year. The authors then repeat this exercise, simulating a pre-industrial climate without human-caused warming.
By comparing the number of heat-stress days in the present-day climate with the number in a pre-industrial climate, the authors can determine how many extra heat-stress days were driven by climate change. They refer to these as “extra” or “attributable” heat-stress days.
The authors find that “low-latitude” countries, located in the tropics, record the most extra heat-stress days.
For example, the paper finds that people living in Côte d’Ivoire currently face 112 heat-stress days every year. It adds that around half of these are due to human-caused climate change.
In contrast, Germany sees only 0.1 heat-stress days per year in today’s climate on average, which is largely attributable to human-caused climate change.
Rosa Pietroiusti, a PhD student at Vrije Universiteit Brussel and lead author on the study, explains why this number may seem lower than expected.
She tells Carbon Brief that the paper “really focuses on humid heat, at levels that are relatively rarely felt in Europe”. She adds:
“Our data also doesn’t capture the urban heat island effect, due to the resolution of the data we use, which also would lead to underestimations of heat stress locally, and lead to a mismatch with what people are experiencing at local scales, particularly in cities.”
Inequality
Extreme heat affects some people more severely than others. Children, people over 65 and those with pre-existing medical conditions or certain disabilities are among the most vulnerable. This is because their bodies are less able to regulate their temperature.
The authors use gridded demographic data to determine the age structure of each country. From this, they calculate how many people from each age cohort are exposed to extra heat days as a result of climate change.
The research finds that globally, 583 million children under the age of 10 already live through at least 20 attributable heat days every year. This accounts for 44% of all children in this age bracket.
In comparison, 190 million people aged 60-69 face at least 20 attributable heat days per year, accounting for 30% of this age cohort.
The authors find that children face the greatest exposure to humid heat for two main reasons.
First, there are more young people alive today than older people, with 1.3 billion children aged under 10 in the world, compared to 0.6 billion people aged 60-69.
Second, they find that countries in Africa and Asia typically have rapidly growing populations with more young children. In contrast, many countries in the northern hemisphere – which are typically cooler – have older populations.
The map below shows how many extra stress heat days each country currently faces as a result of human-caused climate change. Darker reds indicate a higher number of attributable heat days. The blue circles show the percentage of the population under the age of 10, with larger circles indicating a higher percentage.
Warming world
The authors also repeat their analysis for a 1.5C and 2C warmer world. They use population estimates from the SSP2 scenario, which projects that the world’s population will peak at more than nine billion in the second half of the 21st century, with most growth occurring in low-latitude regions – especially in sub-Saharan Africa.
The research finds that, in today’s climate, 11% of all under 10s currently experience 100 or more extra heat-stress days per year due to climate change. In worlds warmed by 1.5C and 2C, the percentage rises to 13% and 23%, respectively.
In contrast, only 6% of all people aged 60-69 currently face 100 or more extra heat-stress days each year due to climate change. This number rises to 9% and 17% for 1.5C and 2C worlds, respectively.
These results are shown in the plot below. The three rows represent the climates of 2023 (top), a 1.5C world (middle) and a 2C world (bottom). The columns show different age cohorts, from the oldest on the left to the youngest on the right.
Each circle contains 100 coloured dots, with each dot representing 1% of the age cohort.
The colour of the dot represents exposure to annual heat-stress day, with darker dots indicating more heat-stress days. Grey dots mean that people experience fewer than one extra heat-stress day per year due to human-caused climate change, while black dots mean more than 150 extra heat-stress days due to climate change.
The figure shows that higher warming levels expose more people to heat stress and that younger cohorts tend to be worst affected.
For example, the top-right circle represents heat stress for under 10s in the present-day climate. Three of these dots are coloured black, indicating that 3% faced at least 150 attributable heat-stress days in 2023.
Pietroiusti tells Carbon Brief the study uses wet-bulb temperature because it is a “well-established heat stress metric”. However, she notes that it was not “explicitly defined to focus on children”. She continues:
“A really important step forward in the research community would be to link up climate science and health science experts to do research on what metrics are really most representative of, for example, health impacts and educational impacts that children will be suffering.”
Vulnerability
Dr Qinqin Kong, a postdoctoral researcher at the departments of medicine and health policy at Stanford University, who was not involved in the study, praises its “robust” methodology.
He tells Carbon Brief that the research provides “a timely quantitative evidence for discussions of climate justice, children’s rights and intergenerational equity”.
However, Kong suggests that the paper “may overstate the contrast between children and the elderly and underestimate the relative burden of older adults”.
He says:
“The elderly may also be more vulnerable due to their social circumstances. Children often benefit from parental supervision and caregiving, whereas many older adults live alone, have limited mobility and face barriers to accessing cooling or emergency assistance during heat events.”
Kong also notes that “people and societies in the mid-latitudes [for example, across much of Europe and North America] are less adapted to heat”, which may make them vulnerable to its impacts.
For example, he says that Europe “shows substantially stronger relative risk of heat mortality likely due to less heat-acclimatised populations, lower air conditioning prevalence and urban designs that don’t favour heat dissipation”.
Similarly, Dr Daniel Vecellio – a researcher at the University of Nebraska, who was not involved in the study – tells Carbon Brief that children are an “understudied cohort”.
However, he says there is “reason for hope” because “children are typically pretty good behavioural adapters to extreme heat” and because people who are “chronically exposed to extreme heat” will “have a better chance at better acclimatisation”.
Pietroiusti tells Carbon Brief that global reporting on heatwaves is often skewed towards wealthier nations.
For example, she notes that large-scale databases of disasters, such as EM-DAT, often underrepresent heatwaves in Africa, due in part to a lack of news coverage and formal reporting. She adds:
“Studies like this, which start from the climate data, can start to fill some of these gaps.”
She adds that the paper should inform discussions about climate justice, noting that children in developing countries, who are most severely affected by the increase in heat-stress days, “have contributed the least to historical greenhouse gas emissions”.
Pietroiusti, R. et al. (2026) Age-specific exposure to human-induced increases in humid heat, Science Advances, doi:10.1126/sciadv.aeb3232
The post Climate change exposes 580 million children to 20 extra ‘heat-stress days’ every year appeared first on Carbon Brief.
Climate change exposes 580 million children to 20 extra ‘heat-stress days’ every year
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