UCL News


New global projections highlight ‘enormous human cost’ to climate inaction

15 November 2023

Delayed action on climate change is costing lives and livelihoods, with people exposed to dangerously high temperatures and predictions of a 4.7-fold increase in heat related deaths by mid-century, finds the latest Lancet Countdown report led by UCL researchers.

Thailand city view in heatwave summer season high temperature from global warming effect

The 2023 Report of the Lancet Countdown on Health and Climate Change delivers a concerning health stocktake, with new global projections revealing the grave and mounting threat to human health as a result of climate inaction.

Key findings of the report include:

  • In 2022, individuals were, on average, exposed to 86 days of health-threatening high temperatures. Of these, 60% were made at least twice as likely to occur because of human-caused climate change.
  • New global projections reveal that the world is likely to experience a 4.7-fold increase in heat-related deaths by mid-century.
  • A new regional section of the report highlights the different and unequal health impacts of climate change, highlighting who is benefitting from climate change adaptation, and the health benefits of the clean energy transition so far.
  • Authors outline how a just energy transition could reduce health inequities and improve the health and wellbeing of all populations.
  • Data from this year’s report reveal a world moving in the wrong direction. Governments, companies and banks continue investing in oil and gas, as the challenges and costs of adaptation soar, and the world approaches irreversible harm.

The report suggests that without profound and swift mitigation to tackle the root causes of climate change, the future health of humanity is at grave risk.

The authors hope that the stark findings will encourage urgent health-centred climate action to shift the global economy to a zero-carbon footing.

Meanwhile, “transformative opportunities”, such as improved energy access and security, cleaner air, safer drinking water, healthier diets and lifestyles, and more liveable cities, could be opportunities to improve the health of world populations.

Executive Director of the Lancet Countdown, Dr Marina Romanello (UCL Institute for Global Health), said: “Our health stocktake reveals that the growing hazards of climate change are costing lives and livelihoods worldwide today. Projections of a 2°C hotter world reveal a dangerous future, and are a grim reminder that the pace and scale of mitigation efforts seen so far have been woefully inadequate to safeguard people’s health and safety.

“With 1,337 tonnes of carbon dioxide still emitted every second, we aren’t reducing emissions anywhere near fast enough to keep climate hazards within the levels that our health systems can cope with.

“There is an enormous human cost to inaction, and we can’t afford this level of disengagement – we are paying in lives. Every moment we delay makes the path to a liveable future more difficult and adaptation increasingly costly and challenging.”

Co-chair of the Lancet Countdown, Professor Anthony Costello (UCL Institute for Global Health), said: “While ambition to unlock money for adaptation will be critical, health-centred action requires urgent mitigation.

“This will require defending people’s health from the interests of the fossil fuel and other health-harming industries. Transformative climate action is needed today to enable a future where present and future generations can thrive.”

The report is launching ahead of the 28th UN Conference of the Parties of the UNFCCC (COP28), which will – for the first time – feature health as a key theme, with an official Health Day and a climate-health ministerial. The Lancet Countdown report contributes to the evidence needed to inform the negotiations and deliver truly health-protecting climate change action. 

Responding to the report publication, UN Secretary-General, António Guterres (who was not involved in writing the report), said: “We are already seeing a human catastrophe unfolding with the health and livelihoods of billions across the world endangered by record-breaking heat, crop-failing droughts, rising levels of hunger, growing infectious disease outbreaks, and deadly storms and floods.

“The continuing expansion of fossil fuels is a death sentence to millions. There is no excuse for a persistent delay in climate action. Temperature rise must be limited to 1.5°C to avert the worst of climate change, save millions of lives, and help protect the health of everyone on earth.”

The report was funded by Wellcome.



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Media contact 

Poppy Danby

E: p.danby [at] ucl.ac.uk