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Lancet Countdown 2023 Report reveals a “grave risk” for the health of humanity

ISGlobal researcher Cathryn Tonne contributes to the 8th annual health and climate change report published in The Lancet


The publication of Lancet Countdown 2023 report delivers a concerning health stocktake, with new global projections revealing the grave and mounting threat to health of further delayed action on climate change. ISGlobal researcher Cathryn Tonne is one of the contributing authors of the eighth annual global report of the Lancet Countdown on Health and Climate Change, which has been published today.

“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”, says Marina Romanello, Executive Director of the Lancet Countdown at University College London.

“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”, says Romanello.

Cathryn Tonne, Research Professor at ISGlobal said: “ We urgently need deep reductions in greenhouse gas emissions across all sectors, scaling up renewable energy and phasing out fossil fuels. The good news is that in doing so, there is an incredible opportunity to reduce energy poverty and save lives through cleaner air.”

Key findings

  • Climate inaction is costing lives and livelihoods today. In 2022, individuals were, on average, exposed to 86 days of health-threatening high temperatures , of which 60% were made at least twice as likely to occur because of human-caused climate change.
  • New global projections reveal the grave and mounting threat to health of further delayed action on climate change, with the world likely to experience a 4.7-fold increase in heat-related deaths by mid-century.
  • New regional section of the report highlights the different and unequal experience of the health impacts of climate change, and who is benefiting from climate change adaptation and the health co-benefits of the clean energy transition so far. Authors outline the opportunity that a just energy transition offers to reduce health inequities and improve the health and wellbeing of all populations.
  • Despite these harms, 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.
  • Without profound and swift mitigation to tackle the root causes of climate change, the health of humanity is at grave risk . The stark findings must force urgent health-centred climate action to shift the global economy to a zero-carbon footing while delivering “transformative opportunities” to improve the health of world populations through improved energy access and security, cleaner air, safer drinking water, healthier diets and lifestyles, and more liveable cities.

Transformative opportunities of health-centred climate action

The failure to seriously mitigate climate change is self-evident in the report, with health-related losses and damages soaring globally. However, the report is launching ahead of the 28th UN Conference of the Parties of the UNFCCC (COP28), where ISGlobal will be present as an observer . For the first time, health will be one of the key themes, 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) says, “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.”

Find out more, and read the full report at

This report was funded by The Wellcome Trust .