New global findings in the 2025 Lancet Countdown on Health and Climate Change reveal that the continued overreliance on fossil fuels and failure to adapt to climate change continues to be paid in people’s lives, health, and livelihoods, with 13 of 20 indictors tracking health threats now reaching unprecedented levels.
The University of Sydney’s Heat and Health Research Centre contributed to the global report of the Countdown, which is published annually by The Lancet , the world’s leading medical research journal and is regularly among its most highly cited articles.
The annual indicator report, now in its ninth year, informs government policy globally with respect to climate change. It covers 50+ indicators tracking the impacts of, and efforts to adapt to, the ongoing health effects of climate change globally across five working groups, representing the work of 128 leading experts from 71 academic institutions and UN agencies globally.
Findings of 2025 report
This year’s report indicates:
Positive action
The report also details actions local governments, individuals, civil society, and the health sector are undertaking to shape a healthier future including:
Professor Anthony Costello, Co-Chair of the Lancet Countdown warned, “As a rising number of world leaders threaten to reverse the little progress to date, urgent efforts are needed at every level and in every sector to both deliver and demand accelerated action that will yield immediate health benefits. As some governments uphold an unsustainable, unhealthy and ultimately unliveable status quo, people around the world are paying the ultimate price. We have to build on the momentum we have seen from local action: Delivering health-protective, equitable, and just transition requires all hands on deck.”
University of Sydney contribution
Ollie Jay , Professor of Heat and Health and Director of the Heat and Health Research Centre (HHRC), is a Chair of the one of the five working groups, Working Group 1, contributing to the global report making the University of Sydney the host institution of the group.
This group addresses all aspects of health impacts and vulnerabilities and has academic oversight of the 20 indicators associated with it, the highest number of the report, including indicators Professor Jay has led on, supported by University of Sydney HHRC researchers Dr Federico Tartarini and Associate Professor Troy Cross.
Dr James Smallcombe , also from the HHRC is the Working Group 1 global fellow and an author on the report.
Professor Jay said, “The findings in this year’s report are sobering, revealing that millions of lives have already been lost unnecessarily due to over-reliance on fossil fuels, rising greenhouse gas emissions, and inadequate adaptation to climate change. The imperative now is to limit future harm by placing human health at the centre of policy decisions. The HHRC at the University of Sydney is proud to be leading several contributions featured in this year’s report—driven by our team of early and mid-career researchers who represent the next generation of leaders the world urgently needs.”
The Lancet Countdown is funded by Wellcome Trust and the online launch event of the global report yesterday was addressed by speakers including:
The 9th Lancet Countdown annual indicator report is led by University College London and is produced in strategic partnership with the World Health Organization (WHO).
The Lancet
Observational study
People
The 2025 report of the Lancet Countdown on health and climate change
28-Oct-2025
PJB, AC, IH, JJH, S-CH, IK, KAM, YP-S, MRo, MW, and HW were compensated for their time while drafting and developing the Lancet Countdown's report via the Lancet Countdown: tracking progress on health and climate change Wellcome Trust grant (grant number 304972/Z/23/Z). MSo, RH, and RK acknowledge the funding of Research Council of Finland VFSP-WASE (grant number 359421), together with the EU Horizon projects FirEUrisk (grant number 101003890) and ClimAir (grant 101156799).