A geoengineering strategy to inject aerosols into the stratosphere could have repercussions, with the potential worsening of a tropical malaria outbreak
The health of billions of people in tropical countries could be at a higher risk of malaria, as geoengineering plans to reduce climate change could pose greater struggles than solutions to global climate problems.
Malaria affects up to 200 million people yearly, claiming over 627,000 deaths in just 2020 – with these cases still rising. Climate change is increasing tropical malaria, due to mosquitos being adaptable to warming climates, which are affecting the tropics the fastest.
“The potential for geoengineering to reduce risks from climate change remains poorly understood, and it could introduce a range of new risks to people and ecosystems.”
According to a new finding by scientists at Georgetown University Medical Center, researchers set out to understand how geoengineering the climate could worsen existing infectious diseases, like malaria.
Solar radiation management can help mitigate climate impact
Solar radiation management (SRM) – an intervention that hypothesises emergency actions aimed at reducing the dangerous impacts of climate change – has been often debated as a method to reduce climate injustice, but it has minimal research discussing the potential impacts on health that it could have.
One action that has been proposed is injecting aerosols into the stratosphere that reflect incoming sunlight, thereby temporarily “pausing” global warming. Researchers just now are realising this could have grave consequences for those already affected by tropical malaria.
Colin Carlson, PhD, said: “The implications of the study for decision-making are significant. Geoengineering might save lives, but the assumption that it will do so equally for everyone might leave some countries at a disadvantage when it comes time to make decisions.
“If geoengineering is about protecting populations on the frontlines of climate change, we should be able to add up the risks and benefits – especially in terms of neglected health burdens, such as mosquito-borne disease.”
Malaria risk is predicted to shift between regions globally
The team of researchers, from the United States, Bangladesh, South Africa, and Germany, used climate models to simulate what malaria transmission could look like in two future scenarios, with medium or high levels of global warming – both with and without geoengineering.
The models demonstrated which temperatures were the most conducive for transmission by the Anopheles mosquito, identifying how many people live in areas where transmission is possible.
In both medium- and high-warming scenarios, malaria risk was predicted to shift significantly between regions; but in the high warming scenario, simulations found that a billion extra people were at risk of malaria in the geoengineered world.
Due to malaria transmission peaking at 25°C, cooling the tropics using geoengineering might ultimately increase malaria risk in some places relative to an alternative future, but might also increase risk in the present day – both outcomes require better international cooperation to tackle tropical malaria and climate change.
There is a need for better geopolitics when discussing climate change strategies
The researchers highlight that one of the most surprising findings was the scale of potential trade-offs between regions, where in both scenarios, geoengineering could actually substantially reduce malaria risk in the Indian subcontinent even compared to the present day – however, this protective effect could be offset with an increase in risk in southeast Asia.
This can complicate global decisions tackling both climate intervention and human health.
Christopher Trisos, PhD, said: “The potential for geoengineering to reduce risks from climate change remains poorly understood, and it could introduce a range of new risks to people and ecosystems.”
Carlson finalised: “We’re so early in this process that the conversation is still about increasing Global South leadership in geoengineering research. Our highlights that the frontlines of climate injustice aren’t one monolithic bloc, especially when it comes to health.
“On a planet that’s too hot for humans, it also gets too hot for the malaria parasite. Cooling the planet might be an emergency option to save lives, but it would also reverse course on those declines.”
