Climate change harms health in all populations. 1 Ebi KL Capon A Berry P et al. Hot weather and heat extremes: health risks. Lancet. 2021; 398: 698-708 Summary Full Text Full Text PDF PubMed Scopus (217) Google Scholar Heat-related illness and deaths are increasing worldwide, from heatstroke, adverse pregnancy outcomes, worsened kidney function, and adverse mental health effects. 1 Ebi KL Capon A Berry P et al. Hot weather and heat extremes: health risks. Lancet. 2021; 398: 698-708 Summary Full Text Full Text PDF PubMed Scopus (217) Google Scholar , 2 Romanello M Di Napoli C Drummond P et al. The 2022 report of the Lancet Countdown on health and climate change: health at the mercy of fossil fuels. Lancet. 2022; 400: 1619-1654 Summary Full Text Full Text PDF PubMed Scopus (150) Google Scholar For those working outdoors, heat limits physical work and labour productivity, undermining livelihoods. 1 Ebi KL Capon A Berry P et al. Hot weather and heat extremes: health risks. Lancet. 2021; 398: 698-708 Summary Full Text Full Text PDF PubMed Scopus (217) Google Scholar Extreme weather events cause illness (eg, through particulate pollution from fires, or water contamination from floods), direct injury (eg, physical injury and drowning), and chronic malnutrition by reducing agricultural output and increasing infections. 1 Ebi KL Capon A Berry P et al. Hot weather and heat extremes: health risks. Lancet. 2021; 398: 698-708 Summary Full Text Full Text PDF PubMed Scopus (217) Google Scholar , 3 Costello A Abbas M Allen A et al. Managing the health effects of climate change: Lancet and University College London Institute for Global Health Commission. Lancet. 2009; 373: 1693-1733 Summary Full Text Full Text PDF PubMed Scopus (1759) Google Scholar Climate change means many infectious diseases expand into previously safe areas and could increase pandemic risk. 1 Ebi KL Capon A Berry P et al. Hot weather and heat extremes: health risks. Lancet. 2021; 398: 698-708 Summary Full Text Full Text PDF PubMed Scopus (217) Google Scholar Loss of physical assets and damage to infrastructure affect essential health and social services and socioeconomic wellbeing. Together, these factors drive population migration, political upheaval, and economic damage, all of which impact health. For these reasons the 2009 Lancet Commission on managing the health effects of climate change 3 Costello A Abbas M Allen A et al. Managing the health effects of climate change: Lancet and University College London Institute for Global Health Commission. Lancet. 2009; 373: 1693-1733 Summary Full Text Full Text PDF PubMed Scopus (1759) Google Scholar described climate change as the “greatest global health threat of the 21st century”. However, it was wrong, both qualitatively and temporally. The threat is now to our very survival and to that of the ecosystem upon which we depend. Grave impacts of climate change are already with us and could worsen catastrophically within decades. A UN Environment Programme report states there is “no credible pathway to 1·5°C in place” today. 4 UN Environment ProgrammeEmissions gap report 2022. Oct 27, 2022. https://www.unep.org/resources/emissions-gap-report-2022Date accessed: November 9, 2022 Google Scholar