Projected malaria transmission risk under climate intervention in South Asia

Abstract This study focuses on the impact of climate intervention under the ARISE-SAI-1.5 scenario of stratospheric aerosol injection (SAI) on projected malaria distribution in South Asia, relative to climate change under the SSP2-4.5 scenario, during the period 2045 to 2069. A dynamic malaria model is employed to assess the impacts of SAI and climate change on malaria redistribution. In addition to the entomological inoculation rate (EIR), the length of the transmission season (LTS) and malaria cases are considered as quantitative indicators of malaria transmission. The quantification of the projected malaria distribution employing several statistical techniques, including the probability density function technique, enables the assessment of malaria variability and risk across all seven highly climate-vulnerable countries of South Asia (Afghanistan, India, Iran, Bangladesh, Bhutan, Nepal, and Pakistan). Due to the lower temperatures achievable under ARISE-SAI-1.5 scenario relative to SSP2-4.5 scenario, the frequency of EIR occurrence shifts toward lower intensity values. This decrease in EIR is more pronounced in populous India and Bangladesh than in the other five South Asian countries during 2045–2069. The projected magnitude of LTS and the frequency of malaria case occurrences also diminish under ARISE-SAI-1.5 in South Asia.