To understand and reduce the long-standing uncertainty in anthropogenic aerosol radiative forcing
The ultimate aim of the FORCeS project is to understand and reduce the long-standing uncertainty in anthropogenic aerosol radiative forcing. This is crucial if we are to increase confidence in climate projections
The Paris Agreement (PA), adopted within the United Nations Framework Convention on Climate Change (UNFCCC) in December 2015, requires the majority of the world’s countries to limit global warming from anthropogenic activities within 2°C above pre-industrial levels. The actions needed to reach this goal, and the urgency and effectiveness of their implementation, rely crucially on accurately predicting the time-evolution of radiative forcing and the resulting climate response . Uncertainty in simulating the components of the atmosphere, especially those related to aerosol, clouds and their interactions severely hampers our ability to understand the past and project future climate change. This is because anthropogenic aerosols exert a net cooling impact on climate that offsets – but with large uncertainty – part of the warming effect from greenhouse gas emissions. As a result, the time left for achieving the necessary greenhouse gas reductions to achieve the PA target, and our understanding of the expected regional impacts of climate change, are hampered by the inability to robustly quantify the anthropogenic climate forcing associated with aerosols. In particular, the anticipated large reductions in aerosol emissions in the coming decades will result in a warming effect that is currently very poorly quantified. It is therefore crucial to establish the extent to which aerosol changes, whether due to anthropogenic emissions or as a feedback induced by warming, offset greenhouse gas warming.