There are still many unanswered questions regarding the impact of climate change on health. It is particularly important to understand the relationship between climate change and non- communicable diseases (NCDs). Climate change will aggravate NCDs, already responsible for more deaths than any other cause on the planet.130 For instance, researchers studying Brazil and Australia131 found that for every 1°C increase in temperature, the estimated risk of hospitalization for renal diseases lasting up to seven days increased by almost 1%. For children, women and those over 80 years old, the risks are even higher. There will also be a higher risk of exposure to air pollution from wildfires and the continued burning of fossil fuels that emit carcinogenic gases such as nitrogen dioxide and sulphur dioxide. For example, air pollution is believed to be responsible for approximately 14% of lung cancer cases worldwide.132 A meta-analysis involving numerous lung cancer cohort studies over the past 25 years found that each 10 µ/m3 increase in PM2.5 exposure is associated with another 14% average increase in lung cancer mortality. There could be a higher incidence and higher mortality rate from chronic disease, as already stretched public health resources are switched from regular surveillance and health promotion activities to combating the climate-health crisis. This is a phenomenon caused by excess demand, as seen during the COVID-19 pandemic.133 Diabetes is a non-communicable disease that could be aggravated by climate change, because of diabetics’ impaired responses to heat stress. This includes compromised vasodilation and sweating, diabetes-related comorbidities and chronic low- grade inflammation.134 Diabetics are also more susceptible to many pathogens because of their altered immune systems.135 It is important to understand the interplay between diseases and to consider how climate-related stresses could disproportionately affect more compromised populations, including those with NCDs. For example, diabetes, obesity and hypertension often coexist136 and could increase the likelihood of climate- driven health complications. COVID sufferers with comorbidities are also more likely to be hospitalized and develop worse symptoms.1373.5 Avenues for further research: how climate affects non-communicable diseases Healthcare in a Changing Climate: Investing in Resilient Solutions 30

Healthcare in a Changing Climate 2025