The heat-related impacts of climate change are becoming increasingly apparent – along with their human toll in deaths and illnesses. WHO Directors of Noncommunicable Diseases and Environment, Climate Change and Health Bente Mikkelsen and Maria Neira call for the prevention of climate- and heat-related diseases to be included on the formal agenda of COP 28 – “not just on the sidelines”. July 2023 was the warmest month on record globally, with far-reaching impacts on human health. Extreme heat can lead to sudden organ failure and death. Chronic heat stress can also trigger or exacerbate several noncommunicable diseases (NCDs) such as kidney disorders, hypertension and cardiovascular and respiratory diseases, leading to premature deaths. In addition to heat waves, extreme weather events such as floods and storms also pose risks to people living with NCDs, when routine health services and access to life-saving medicines are disrupted. Displacement and trauma following extreme weather can also exacerbate mental health conditions. Yet noncommunicable diseases, such as those caused by heat and climate stress, are not yet on the agenda of the 28th United Nations Climate Change Conference (COP28), which is due to begin in Dubai on 30 November. While its hosts have pledged to elevate health issues to the forefront, WHO’s directors for noncommunicable diseases and environment, climate change and health, Bente Mikkelsen and Maria Neira, are now urging that preventing noncommunicable diseases caused by heat and other climate-related events be included on the formal agenda of the COP28 negotiations.