Healthcare in a Changing Climate 2025

Preparing for the climate-induced health crisis 1 Preparing for the climate crisis requires investing in resilient systems, boosting innovation and implementing enabling policies. High-priority strategies A short five years from now, the global economy should have cut 45% of its annual greenhouse gas emissions,7 in line with the 2015 Paris Agreement on climate. But as of today, maintaining flat emissions in the face of economic expansion is the principal achievement of the global community. Even if new low-carbon or no-carbon technology is fully scaled- up in the next two decades, policy-makers and the public need to prepare for the effects of more significant global warming — with some of the most severe impacts affecting human health. Climate events such as flooding, heatwaves, tropical storms and wildfires are already having a significant impact on public health. The increasing frequency and intensity of these events – together with longer term trends such as desertification, rising sea levels and changing habitats for the vectors of disease – are likely to trigger a climate health emergency. If the impact of biodiversity loss on health is also factored in, the consequences for human health will potentially be even greater. The complex links between climate change, biodiversity loss and human health warrant further research. For instance, global warming is already causing8 significant increases in vector-borne diseases such as malaria, dengue fever, Zika, West Nile, Lyme disease and tick-borne encephalitis, with spikes in populations9 of mosquitos, ticks and other vectors. Hotter and wetter weather means an increase in the breeding periods of vectors as well as an extension of their geographic range. Already, there have been reported cases of dengue and malaria in North America and Europe and it is probable that those numbers will begin rising quickly.10 This combination of factors is likely to expose 500 million more people to such diseases by 2050, as disease-carrying vectors begin to be found routinely in Europe and North America.* Relationship between climate impacts and health outcomes Understanding the cascading effects of climate events provides valuable insights into the cause- and-effect relationship between climate impacts and health outcomes, which involve both direct and indirect consequences from these events. More immediate impacts include death, physical injuries, malnutrition, respiratory and cardiovascular ailments and exposure to infectious diseases, including vector-borne malaria and dengue, plus diseases caused by contaminated water or food, such as cholera and dysentery. Additional long-term and indirect impacts will likely include heat-stress associated risks11 to maternal health that can lead to higher incidences of miscarriage, premature birth, low birth weights and potentially stunted infant growth.12 Stunted development will also be seen among children suffering from drought-related malnutrition. Further impacts include respiratory and cardiovascular diseases triggered by deteriorating air quality from wildfires or prolonged heatwaves. Longer term, climate-related events will impact both individuals and societies. The stress, trauma and displacement caused by climate-related disasters can be expected to produce a surge in mental health illnesses,13 including anxiety, depression 1.1 Quantifying the impact of future climate events on public health Global warming is already causing significant increases in vector-borne diseases – 500 million more people are likely to be exposed to such diseases by 2050. * Core datapoints in Chapters 1 and 2 of this report on climate-related impacts to mortality and economic costs by 2050 are sourced from: World Economic Forum. (2024). Quantifying the Impact of Climate Change on Human Health, written in collaboration with Oliver Wyman. Healthcare in a Changing Climate: Investing in Resilient Solutions 6