Global warming linked to a significant rise in mortality, study finds

Yesterday 10:25

By: Azzat Manal

Global warming linked to a significant rise in mortality, study finds

Global warming may have a far greater impact on human mortality than the direct health effects of local heat exposure, according to a study by researchers from Stanford University and Northwestern University.

The research, published in September 2026, estimates that a sustained 1-degree Celsius increase in global temperatures could be associated with around 2.5 additional deaths per 1,000 people each year. By comparison, estimates based solely on people's direct exposure to local temperature changes point to an increase of about 0.1 deaths per 1,000.

The researchers argue that economic damage caused by climate change accounts for roughly two-thirds of the wider mortality effect. Lower incomes, reduced economic activity and pressure on public health systems can amplify the consequences of rising temperatures, particularly in poorer countries.

The study examined data from more than 100 countries covering around 70% of the world's population between 1960 and 2019. To identify the long-term effects of temperature changes, the researchers used naturally occurring climate fluctuations associated with El Niño events, solar activity and volcanic eruptions, which they considered less directly connected to economic and health conditions.

The analysis found that the mortality impact can persist for years after a temperature shock, reaching its highest estimated level around 12 years later. Older people appear particularly vulnerable, with the effect estimated to be several times higher among those aged over 65.

Economic losses were identified as a major pathway linking climate change to mortality. The researchers estimate that a permanent 1-degree Celsius increase in global temperatures could reduce global output per person by about 22% over the long term. Based on previous research connecting income levels with mortality, they attribute about 66% of the overall mortality impact to economic losses.

Direct effects linked to extreme weather conditions, including heat, cold, drought and storms, account for a smaller share of the estimated increase. Cardiovascular diseases and HIV-related deaths were among the causes most strongly associated with the additional mortality in the study, while deaths directly attributed to heat or cold represented a comparatively limited portion.

The burden is expected to be particularly severe in poorer regions with weaker public health systems. The researchers found that parts of Africa could experience mortality increases exceeding two additional deaths per 1,000 people under the scenarios examined.

Under a scenario in which global temperatures rise by another 2 degrees Celsius by 2100, the study estimates an increase of roughly six deaths per 1,000 people. It also places the social cost of carbon at around $1,640 per tonne, with mortality accounting for approximately $400 of that amount.

The researchers stress that the findings come with important limitations. Applying estimates derived from temporary temperature shocks to permanent long-term warming requires assumptions about how the relationship between climate and mortality behaves outside the observed range. The actual impact could therefore be either higher or lower than the study's estimates.

The findings nevertheless suggest that climate policies may have health benefits extending well beyond preventing heat-related deaths. Limiting emissions and protecting economic activity could simultaneously reduce climate-related economic losses and some of the longer-term risks to human health.