The important role of African emissions reductions in projected local rainfall changes

Few global climate modelling experiments have addressed how changes in African aerosol emissions can have relatively large local climate impacts. Building on the results of the Integrated Assessment of Air Pollution and Climate Change for Sustainable Development in Africa undertaken by the Climate and Clean Air Coalition, the UN Environment Programme and the African Union Commission, this study used data generated with SEI’s Low Emissions Analysis Platform (LEAP) in combination with NASA’s Goddard Institute for Space Studies (GISS) climate model to simulate the effect of reduced cooling aerosols emissions on regional precipitation patterns.

The data for the GISS models came from several LEAP scenarios, ranging from a baseline “business as usual” scenario to one which incorporated numerous mitigation strategies aligned with the African Union’s Agenda 2063 strategy, “The Africa we want”, which articulates a vision for sustainable development in Africa.

After running simulations from 2015–2064 for all scenarios, they found a modest warming associated with reductions in aerosol emissions – a climate penalty related to the reduction in cooling aerosols. However, the researchers also determined that when coupled with decarbonization strategies, a reduction in cooling aerosols also led to wetter conditions for tropical Africa, especially West Africa, as well as considerable public health benefits from the particulate matter reductions. The authors also noted that reductions in cooling aerosols have little impact on winter precipitation in both southern and northern Africa.

The models show that lower aerosol emissions may provide some significant climate benefits via reduced disruption of precipitation patterns, and this emphasizes the fact that rather than simply being affected by what the rest of the world chooses to do about emissions reductions, Africa can, to some extent, affect its climate future.