While warmer temperatures have long been understood to facilitate the spread of malaria – by expanding the range of the insects that carry it – analysis of the past 25 years reveals that temperature isn’t the biggest concern.
A recent analysis published in the journal Nature distinguishes between two distinct ways climate change can impact malaria in the near future: gradual changes to the environment – such as a slow expansion of an insect’s territory – and “climate shocks” like floods or hurricanes, which displace millions and temporarily disrupt medical aid. Understanding these different pathways is crucial for effective public health planning.
This distinction is important, write two environmental science researchers commenting on the study in Nature, because recent years have shown that climate change will increasingly manifest as more extreme weather events, rather than solely through gradual temperature increases. However, projections regarding future disease burdens have often relied on scenarios of gradual change – how many degrees Celsius by 2050, how many people at risk in newly mosquito-covered ecosystems, and so on.
Across Africa, these researchers from the University of Oxford and the University of Iowa write, “the picture changes radically when extreme weather is taken into account.” The increase in floods and hurricanes could lead to 123 million additional malaria cases and over 500,000 deaths by 2050 if the planet continues to warm at the current rate. More than three-quarters of this increase would not be the result of expanding mosquito habitats, but rather the result of “disruptions: damaged homes, interruption of insecticide-treated net distribution, and reduced access to treatment.”
the vast majority of these fresh cases would occur in regions already at high risk, densely populated areas (such as southern Nigeria and the Great Lakes region), and among poorer, more vulnerable populations. This highlights the disproportionate impact of climate change on communities with limited resources.
This concerning news arrives alongside positive developments: malaria has been in decline in recent decades thanks to improved distribution of mosquito nets and better access to care. But “these gains are fragile” and protecting them requires addressing “problems that are much more difficult to solve than mosquito abundance: poverty, fragile infrastructure, and health systems straining under pressure.”
