In 2023, global heat-related deaths among people over 65 soared by an unprecedented 167% compared to the 1990s — well beyond the 65% rise anticipated without climate change, finds the Lancet Countdown 2024 Report. What is more, the number of health-threatening heat days added by climate change is higher in countries with a low human development index.

Published ahead of the 29th UN Conference of the Parties (COP29) being held in Azerbaijan from November 11 to 22, the report provides the most up-to-date assessment of the links between health and climate change, including new metrics which record extreme precipitation, stranded coal assets, tree cover loss, sand and dust storms, rising nighttime temperatures and sleep loss, and climate and health education and training.  

According to the report, people were exposed to an average of 1,512 hours of high temperatures that posed a moderate heat stress risk during light outdoor activities like walking or cycling. This marks a 27.7% increase (328 hours) compared to the annual average in the 1990s.

Increasing temperatures have also led to a record 512 billion potential hours of labour lost globally in 2023 - a 49% increase above the 1990-1999 average. The potential global income losses are equivalent to US$835 billion - representing a substantial proportion of GDP in low-income countries (7.6%) and middle-income countries (4.4%).

Extreme precipitation

During the last decade (2014-2023),  61% of the global land area saw an increase in extreme precipitation events compared to the 1961-1990 average, increasing the risk of flooding, infectious disease, and water contamination, the report adds.

More frequent heatwaves and droughts were responsible for 151 million more people experiencing moderate to severe food insecurity in 124 countries in 2022, than annually between 1981 and 2010. 

As a result, the report estimates the total yearly value of economic losses linked to physical assets rather than ill-health resulting from extreme weather events at US$227 billion from 2019-2023, a value that exceeds the GDP of 60% of the world’s economies.

Mosquito-borne diseases

The climatic suitability for the spread of deadly mosquito-borne infectious diseases has also increased. For example, the transmission risk of dengue by Aedes albopictus mosquitoes rose by 46% and Aedes aegypti by 11% over the last decade (2014-2023) compared to 1951-1960. An all-time high of over 5 million dengue cases were reported in over 80 countries/territories in 2023.

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