Revealed: Missing 1.5°C temperature goal would condemn 38 million young children to unprecedented heatwaves in their lifetime

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BRUSSELS, 7 May 2025 – Failure to limit global heating to 1.5°C would condemn nearly a third of today’s five-year olds to unprecedented levels of dangerous heat during their lifetimes, new research has revealed.

The figures, released by Save the Children and Vrije Universiteit Brussel (VUB) and published in Nature, map out the scale of climate extremes children will face at different levels of warming.

Under current climate commitments – which leave the world on course for 2.7°C above pre-industrial levels – about 100 million of the estimated 120 million children born in 2020 will face unprecedented lifetime exposure to extreme heat.  

Hitting the 1.5°C Paris Agreement target would reduce this number to 62 million, protecting 38 million children from dangerous heat that can be deadly for children. Heatwaves take an immense toll on children’s physical and mental health, disrupting access to food and clean water and forcing schools to close. 

The current course will also send millions hurtling towards unprecedented levels of climate extremes, including cyclones and crop failures. 

Over the lifetimes of children born in 2020, keeping to a 1.5°C rise rather than 2.7°C by 2100 would spare around: 

• 38 million from unprecedented exposure to heatwaves

• 8 million from unprecedented exposure to crop failures 

• 5 million from unprecedented exposure to river floods

• 5 million from unprecedented exposure to tropical cyclones

• 2 million from unprecedented exposure to droughts

• 1.5 million from unprecedented exposure to wildfires

Researchers defined an “unprecedented” life as an exposure to climate extremes that someone would have less than a 1 in 10,000 chance of experiencing during their life in a world without human-induced climate change. 

Shruti Agarwal, Senior Climate Change Adviser at Save the Children said:
“Across the world, children are forced to bear the brunt of a crisis they are not responsible for. Dangerous heat that puts their health and learning at risk; cyclones that batter their homes and schools; creeping droughts that shrivel up crops and shrink what’s on their plates.  

“Amid this daily drumbeat of disasters, children plead with us not to switch off. This new research shows there is still hope, but only if we act urgently and ambitiously to rapidly limit warming temperatures to 1.5°C, and truly put children front and centre of our response to climate change at every level.” 

At COP29, the UK Prime Minister committed to ensure “our children have the prosperity, the security and the stability that they deserve for generations to come” and to renew UK climate leadership.

Save the Children said the Comprehensive Spending Review and the upcoming COP30 are critical moments to back up these promises with concrete measures that stand up for children and families on the frontlines of the climate crisis. 

The aid agency said this must start with reversing or mitigating the decision to slash the aid budget from 0.5% of GNI to 0.3% by 2027, which will hugely undermine its ability to tackle climate change internationally and at home. It added that the UK needs to go further to urgently find new sources of public funding for climate action by making the biggest and richest polluters pay.

Save the Children’s second Born into the Climate Crisis report details how climate extremes – which are becoming more frequent and severe due to climate change – are increasingly harming children, forcing them from their homes, putting food out of reach, damaging schools and increasing risks like child marriage as they are forced out of education and into poverty and food shortages. 

Denise*, 16, and her family were forced from their home in Brazil when the country’s worst floods in 80 years devastated their community last year. Their home, including Denise’s bedroom, was severely damaged, and she was out of school for nearly two months.  

She said: “It really affected me mentally, and academically too. Catching up on all my grades to pass secondary school was really tough, especially at a state school. It massively impacted my schoolwork. My grades dropped significantly after the floods.” 

Children impacted by inequality and discrimination and those in lower-and middle-income countries, are often worst affected. Meanwhile they have fewer resources to cope with climate shocks and are already at far greater risk from vector and waterborne diseases, hunger, and malnutrition, and their homes are often more vulnerable to increased risks from floods, cyclones and other extreme weather events.  

Haruka, 16, whose poem is featured in the report, is from Vanuatu, which recently experienced three of the most severe types of cyclone in just a year. She said:   

“Cyclones are scary. For me, they continue to destroy my home, every year - we don't even bother trying to fix the ceiling anymore.  

“The past few years, I've seen ceaseless destruction and constant rebuilding. This seemingly never-ending cycle has become our reality, and most people aren't even aware that it's not just nature doing its thing, but it's us bearing the brunt of a crisis that we did not cause.”   

As well as comparing conditions under 1.5°C and 2.7°C scenarios, the report also examines a scenario in which global temperatures rise to 3.5°C by 2100, which will lead to about 92% of children born in 2020 – about 111 million children – living with unprecedented heatwave exposure over their lifetime.  

While we need a rapid and equitable phase-out of the use,  subsidy and financing of fossil fuels to stick to the 1.5°C target, we must not lose sight of solutions, Save the Children said. The report highlights initiatives like increased climate finance, child-centred and locally led adaptation and increasing the participation of children in shaping climate action. 

Save the Children supports children and their communities globally in preventing, preparing for, adapting to, and recovering from climate disasters and gradual climate change. We have set up floating schools, rebuilt destroyed homes and provided cash grants to families hit by disasters. 

We also work to influence governments and other key stakeholders on climate policies, including at the UNFCCC COP summits, giving children a platform for their voices to be heard. 

ENDS 

NOTES TO EDITORS   

Summary of Save the Children’s recommendations:  

Leaders must: 

• Take ambitious and urgent action now to limit warming to a maximum of 1.5°C above pre-industrial levels, including by rapidly and equitably phasing out the use, subsidising and financing of fossil fuels, with high-income and historically high-emitting countries leading the way.  

• Urgently close the adaptation gap and provide loss and damage funding through the provision of new and additional climate finance, prioritising children and child-critical social services, with a particular focus on reaching children most at risk. Climate finance should be delivered primarily in the form of grants, particularly for adaptation and loss and damage. 

• Children, their rights, voices and unique needs and vulnerabilities must be centred in international climate plans and agreements, including the upcoming submission of new Nationally Determined Contributions (NDC 3.0), as well as building and investing in the climate resilience of child-critical services such as health and nutrition, water, sanitation and hygiene (WASH), education, child protection, and social protection. 

Additional data: 

• *Children born in 2020 (“today’s five-year-olds”), measured against the 2020 birth cohort of about 120 million. 

• Example interpretation of the table: Under a 1.5°C compatible warming pathway, about 62 million children born in 2020 will experience unprecedented lifetime exposure to heatwaves, corresponding to 52% of all children born in 2020.  

• NB: Numbers in the table have been rounded up or down to the nearest integer. Please note that all these figures and the 120 million total birth cohort are all approximations and rounded up/down. Exact figures are available on request. 

• Please note that all these figures are based on predictive modelling from scientists at VUB. 

Endnotes:   

• For this research, scientists have defined a heatwave as: when the daily Heat Wave Magnitude Index of that year exceeds the 99th percentile of pre-industrial Heat Wave Magnitude Index distribution for the specific climate model grid cell. The Heat Wave Magnitude Index measures how intense a heatwave is during a year. It looks at the hottest stretch of at least three days in a row when temperatures are much higher than what was normal before industrial times. The higher the number, the more extreme the heatwave.  

• Ten years ago, world leaders at the UNFCCC COP21 summit in Paris agreed on a long-term goal to limit global temperature rise to 2°C above pre-industrial levels by 2100. The treaty also states that preferably this would be limited to below 1.5°C.

• To achieve these emissions reductions, signatories to the Paris Agreement must pledge NDCs and update these every five years. According to the latest available data, the pledges currently being implemented will see global temperatures rising to 2.7°C above pre-industrial levels by 2100. We also look at a 3.5°C scenario, a near-worst-case outcome that assumes continued high emissions and insufficient mitigation efforts which is worryingly close to the 3.2°C warming we are currently headed towards.  Both these scenarios will have an unacceptable and deadly impact on children. Some signatories to the Paris Agreement submitted new NDCs earlier this year, but many are delayed in their submission and the full picture won't be available before the end of 2025.

• This new report follows a groundbreaking report from 2021 looking at the projected increase in climate extremes faced by children. 

• 111 million is 92% of the 2020 birth cohort of about 120 million children, as detailed in Global emergence of unprecedented lifetime exposure to climate extremes, the research underpinning this report. 

Methodological note  

This report is a collaborative product, with significant contributions from researchers from Vrije Universiteit Brussel, Save the Children experts, and a child reference group of 28 children from Colombia, Vanuatu, New Zealand, Ukraine, Albania, Sierra Leone, China and Yemen who ensured a comprehensive and child-centred perspective on climate action. The findings on climate risks and its impacts are based on five data analysis sources from Vrije Universiteit Brussel, including newly generated simulations of climate impacts across six climate extremes (heatwaves, crop failures, river floods, tropical cyclones, droughts, wildfires), and global mean temperature scenarios based on Intergovernmental Panel on Climate Change (IPCC) 6th Assessment Report Scenario Explorer [i].  

Moreover, country-level life expectancy provided by the United Nations World Population Prospects, population reconstructions and projections by the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) database, and country-scale cohort size data provided by the Wittgenstein Centre for Demography and Global Human Capital’s Data Explorer were used in the analysis. The research methodology integrates these diverse datasets to calculate the lifetime exposure of people to climate extremes in 177 countries, across regions and globally. This is achieved by mapping the projected climate extremes along various global mean temperature trajectories, which are then crossed with life expectancy and population data to calculate conservative estimates of the lifetime exposure to climate extremes for different generations of people. 

The context for this analysis is provided by the initial set of climate action commitments (Nationally Determined Contributions) announced following the Paris Agreement. The findings 34 highlight intergenerational inequalities in exposure to climate extremes and underscore the critical need for robust climate action to minimise impacts on children and future generations. The extent to which current and future generations will experience a warmer and, as a result, a different world with greater climate impacts depends on the choices we make now, which will shape future greenhouse gas emission scenarios, ranging from the optimal situation of very low emissions to the extreme case of very high emissions [ii].  

The analysis refers to three global warming scenarios by the year 2100, compared to pre-industrial temperatures:  

• a 1.5°C scenario, which aligns with the ambitious objective of the Paris Agreement and requires significant and rapid reductions in greenhouse gas emissions.  

• a 2.7°C scenario, which reflects the expected heating based on current mitigation policies and pledges, as estimated by the Climate Action Trackerl [iii] .  

• a 3.5°C scenario, a near-worst-case outcome that assumes continued high emissions and insufficient mitigation efforts.   

These scenarios are crucial for modelling and comparing the potential long-term impacts of the climate crisis on populations, and emphasise the urgency of taking action to mitigate future climate risks.   

To assess how socio-economic vulnerability exacerbates unprecedented lifetime exposure to heatwaves, the study employs two indicators. In addition to gross domestic product (GDP), the analysis relies on the Global Gridded Relative Deprivation Index (GRDI), which rates multidimensional deprivation and poverty through a combination of factors including the ratio of children to working-age population, infant mortality rates, human development levels, and the contrast between rural and urban populations. While these indicators do not directly account for potential adaptations to climate change, they provide insight into the current capacity of populations to adapt. The study then maps the unprecedented exposure to heatwaves of the 20% most and least vulnerable as indicated by GDP and GRDI across the three global warming scenarios mentioned above for different generations.  

It is important to acknowledge that climate and impact models such as the ones this analysis is based on – while invaluable for projecting future climate scenarios – have inherent limitations and uncertainties. These models produce simulations that rely on a mathematical representation of the climate that is limited by the models’ spatial resolution, and what these attempt to project into the future is historical data that may have gaps and may not fully capture future climate conditions. The rate of climate warming is influenced by complex interactions between emissions and various processes that can either mitigate or amplify atmospheric climate cycles. Scientists remain uncertain about several factors, such as the interaction between water vapour and aerosols in cloud formation, which may have cooling or warming potential, and they cannot predict natural phenomena like volcanic eruptions. Additionally, potential tipping points in the climate system and the unpredictable nature of human behaviour add layers of uncertainty. These complexities highlight challenges in predicting precise climate scenarios especially over the longer-term, underscoring the need for adaptive and flexible climate strategies.   

The findings on promising responses to climate risks for children and good practices in child-centred or child-responsive, locally led adaptation are based on a systematic scoping of evidence. This review focused on the most promising responses to climate risks for children across six priority sectors for Save the Children’s climate work: health, WASH (water, sanitation 35 and hygiene), education, child protection, food and nutrition security and livelihoods, and social protection. It was conducted by Lezlie Morinière and Charlotte Gendre of Integrated Risk Management Associates LLC (IRMA).  

[i] Edward Byers, Volker Krey, Elmar Kriegler, Keywan Riahi, Roberto Schaeffer, Jarmo Kikstra, Robin Lamboll, Zebedee Nicholls, Marit Sanstad, Chris Smith, Kaj-Ivar van der Wijst, Alaa Al Khourdajie, Franck Lecocq, Joana Portugal-Pereira, Yamina Saheb, Anders Strømann, Harald Winkler, Cornelia Auer, Elina Brutschin, Matthew Gidden, Philip Hackstock, Mathijs Harmsen, Daniel Huppmann, Peter Kolp, Claire Lepault, Jared Lewis, Giacomo Marangoni, Eduardo Müller-Casseres, Ragnhild Skeie, Michaela Werning, Katherine Calvin, Piers Forster, Celine Guivarch, Tomoko Hasegawa, Malte Meinshausen, Glen Peters, Joeri Rogelj, Bjorn Samset, Julia Steinberger, Massimo Tavoni, Detlef van Vuuren. AR6 Scenarios Database hosted by IIASA. International Institute for Applied Systems Analysis, 2022.  

[ii] IPCC, 2023: Summary for Policymakers. In: Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, H. Lee and J. Romero (eds.)]. IPCC, Geneva, Switzerland, pp. 1-34, doi: 10.59327/IPCC/AR6-9789291691647.001. 

[iii] Climate Action Tracker (2024). 2100 Warming Projections: Emissions and expected warming based on pledges and current policies. November 2024. Available from https://climateactiontracker.org/global/temperatures/. Copyright ©2024 by Climate Analytics and New Climate Institute. All rights reserved. 

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