A new study from the University of Oxford has issued a stark warning about the future of global temperatures, finding that nearly half of the world’s population could be living under conditions of extreme heat by 2050. If global warming reaches 2°C above pre-industrial levels—a scenario climate scientists see as increasingly likely—around 3.79 billion people could experience dangerously high temperatures, reshaping daily life across the planet.

The findings, published in Nature Sustainability, suggest that the impacts of rising temperatures will be felt much sooner than expected. In 2010, approximately 23% of the global population lived with extreme heat; this figure is projected to rise to 41% in the coming decades. The study warns that many severe changes will occur even before the world crosses the 1.5°C limit set by the Paris Agreement.

Central African Republic, Nigeria, South Sudan, Laos, and Brazil are expected to see the largest increases in dangerously hot temperatures

According to the study, countries such as the Central African Republic, Nigeria, South Sudan, Laos, and Brazil are expected to see the largest increases in dangerously hot temperatures. Meanwhile, some of the world’s most populous nations—including India, Nigeria, Indonesia, Bangladesh, Pakistan, and the Philippines—will have the highest numbers of people exposed to extreme heat.

The research also shows that colder countries such as the United Kingdom, Canada, Sweden, Finland, Norway, and Ireland could experience relatively dramatic increases in the number of hot days. Compared with the 2006–2016 period, warming to 2°C could lead to a 150% increase in extreme heat days in the UK and Finland, and more than a 200% increase in countries such as Norway and Ireland.

This raises concerns because infrastructure in colder regions is largely designed to retain heat rather than release it. Buildings that maximise insulation and solar gain may become uncomfortable—or even unsafe—during hotter periods, placing additional strain on energy systems and public health services.

Dr Jesus Lizana, lead author of the study and Associate Professor of Engineering Science at the University of Oxford, said the most critical changes will occur sooner than many expect. “Our study shows most of the changes in cooling and heating demand occur before reaching the 1.5°C threshold, which will require significant adaptation measures to be implemented early on,” he said. He added that many homes may need air conditioning within the next five years, even though temperatures will continue to rise if global warming reaches 2°C.

Dr Lizana also emphasised the need to address climate change without increasing emissions. “To achieve the global goal of net-zero carbon emissions by 2050, we must decarbonise the building sector while developing more effective and resilient adaptation strategies,” he noted.

Dr Radhika Khosla, Associate Professor at Oxford’s Smith School of Enterprise and the Environment and leader of the Oxford Martin Future of Cooling Programme, described the findings as a wake-up call. “Overshooting 1.5°C of warming will have an unprecedented impact on everything from education and health to migration and farming,” she said, adding that sustainable development and renewed political commitment to net-zero emissions remain the most established pathway to reversing the trend of ever-hotter days.

Rising temperatures will have far-reaching impacts beyond discomfort. Demand for cooling systems is expected to rise sharply, particularly in regions that already struggle with access to electricity. At the same time, demand for heating may decline in colder countries, leading to uneven shifts in global energy use.

Dr Luke Parsons, a senior scientist at The Nature Conservancy, said the study adds to evidence that heat exposure in vulnerable communities is accelerating faster than previously predicted. He noted that communities least responsible for climate change often face the harshest impacts, underscoring the environmental justice dimensions of the crisis. Addressing the challenge, he said, will require urgent action on both mitigation and adaptation, including rapid emissions reductions and the expansion of equitable cooling solutions.

As global temperatures continue to rise, extreme heat is no longer a distant threat. It is a present and growing challenge that will shape health, livelihoods, and living conditions for billions of people unless decisive action is taken.

On Health Day at COP30 (November 13), global health and climate experts warned that the world is dangerously underprepared for the accelerating health impacts of climate change, calling for a dramatic scale-up of adaptation finance to protect vulnerable populations.

Speaking at a press conference hosted by Regions4, the Global Climate & Health Alliance and CarbonCopy, leaders from research institutions and national governments said climate-linked health threats — from extreme heat to wildfire smoke — are rising sharply while funding remains “colossally” insufficient.

“Each year, more than half a million lives are lost due to heat, and over 150,000 deaths are linked to wildfire smoke exposure,” said Dr. Marina Romanello, Executive Director of the Lancet Countdown. “Health systems, already stretched and underfunded, are struggling to cope with these growing pressures, and most are still unprepared for what is coming.”

Romanello added that despite the scale of the crisis, “only 44% of countries have costed their health adaptation needs, and existing finance falls short by billions. Without urgent investment, we will not be able to protect populations from escalating climate impacts.”

Adaptation gap continues to widen

The speakers described health-sector underfunding as a critical part of the broader adaptation finance gap. The latest UNEP Adaptation Gap Report estimates developing countries will need $310–365 billion annually by 2035, while the international community is still struggling to mobilise even the $40 billion Glasgow Pact Goal.

“With regards to finance, the reality is that we have a deficit that is quite colossal,” said Carlos Lopes, Special Envoy for Africa, COP30 Presidency. “Most of the efforts are from national authorities. What we need from international finance is that it must be complementary.”

Lopes cautioned that climate and health policy still operates in “multiple contested layers,” warning that unless these are aligned, “we risk losing coherence in our global response.”

Countries highlight urgent needs

Representatives from Bangladesh, Nigeria, India and Chile echoed concerns that adaptation finance is far from matching on-ground needs.

“Our adaptation financing for health is far below what is needed. The gap between what we require and what we receive is enormous,” said Md Ziaul Haque, Additional Director General, Ministry of Environment, Bangladesh. He urged multilateral finance entities to bring forward “concrete, holistic proposals that match the scale of the challenge.”

Nigeria’s challenges are equally stark. “In Nigeria, we are facing an additional 21% disease burden due to climate change… yet the adaptation finance we received in 2021–22 only met 6% of our needs,” said Oden Ewa, Commissioner for Special Duties and Green Economy Lead. He called adaptation finance a “lifeline that saves lives, strengthens communities, and protects economies.”

India outlines its adaptation burden

India also presented updated estimates of its climate adaptation needs. “India will require $643 billion between now and 2030 to adapt to climate change under a business-as-usual scenario,” said Dr. Vishwas Chitale of the Council for Energy, Environment & Water. He noted that India has already made “significant progress, spending $146 billion in 2021–2022 alone — 5.6% of GDP.”

New funding coalition signals momentum

Speakers highlighted the launch of the Climate and Health Funders Coalition, which has committed an initial $300 million annually.

“This is an encouraging signal… It shows that the world is beginning to recognise that protecting health must be at the centre of climate adaptation,” said Jeni Miller, Executive Director, Global Climate & Health Alliance.

Health at the centre of adaptation

Chile stressed the need for integrated policy approaches.

“It is vital to combine the efforts of different ministries — not only health but also transport, energy and food production — so that we generate co-benefits across sectors,” said Dr. Sandra Cortes, President of Chile’s Climate Change Scientific Committee. “A more integrated approach will allow us to improve public health, reduce emissions and create fairer, more sustainable development opportunities.”

As negotiators continue discussions in Belém, experts reiterated that adaptation finance — especially for health — must be just, equitable, accessible and prioritise the most climate-vulnerable nations. The recently proposed Belém Health Action Plan and the Global Goal on Adaptation are expected to serve as frameworks for strengthening health system resilience worldwide.

A new MIT-led study reveals how key mucus molecules naturally shield the gut from dangerous bacteria like Salmonella. The breakthrough opens new pathways for affordable, preventative treatments for travelers and soldiers at risk of infection.

Researchers at MIT have discovered new powerful ways the body guards itself from dangerous bacteria: by deploying mucins, special molecules in mucus that neutralize microbes and stop infection before it starts. The team identified mucins—especially MUC2 and MUC5AC—in the digestive tract that shut down the genetic machinery Salmonella uses to invade cells and cause diarrhea.

“By using and reformatting this motif from the natural innate immune system, we hope to develop strategies to preventing diarrhea before it even starts. This approach could provide a low-cost solution to a major global health challenge that costs billions annually in lost productivity, health care expenses, and human suffering,” said Katharina Ribbeck, the Andrew and Erna Viterbi Professor of Biological Engineering at MIT, in a media statement.

In experiments, exposing Salmonella to the intestinal mucin MUC2 blocked the bacterial proteins that enable infection, turning off the critical regulator HilD. The study also found that a similar mucin from the stomach, MUC5AC, works the same way—and both molecules appear to protect against multiple foodborne germs triggered by similar genetic switches.

“We discovered that these mucins not only create a physical shield but also actively control whether pathogens can turn on genes needed for infection,” Ribbeck explained in the media statement.

Lead authors Kelsey Wheeler and Michaela Gold say synthetic versions of these mucins could soon be added to oral rehydration salts or chewable tablets, providing practical protection for troops, travelers, and people in high-risk areas. According to Wheeler, “Mucin mimics would particularly shine as preventatives, because that’s how the body evolved mucus — as part of this innate immune system to prevent infection,” she said.