2023 saw the highest global temperatures in over 100 000 years, with some of the hottest months on record. Greenhouse gas emissions reached record levels in 2022 despite commitments by countries in the 2015 Paris Agreement to limit the global temperature increase to less than 1·5°C above pre-industrial temperatures. Estimates suggest a potential 2·7°C increase by 2100 unless commitments to transition from fossil fuels are met. Not only do global warming and anthropogenic climate change have profound effects on the planet’s environmental systems, but the seemingly inexorable temperature rise will also have catastrophic effects for human health and wellbeing, with implications for populations affected by HIV.