Climate impacts on soil erosion and muddy flooding at 1.5°C vs 2°C warming

Following the 2015 ‘Paris Agreement’ that seeks to contain global mean temperature increase (GMTI) to well below 2°C and more ambitiously within 1.5°C, recent studies have begun assessing the response of various sectors to these levels of warming. Most studies have so far concentrated on temperature-sensitive sectors. Given the links between a warmer atmosphere and rainfall intensity, there is also a need to examine impact sectors driven primarily by changing rainfall characteristics. One example is soil erosion and muddy flooding from agricultural land, which damages the natural and built environment. Using a case-study hillslope in eastern Belgium—an area particularly impacted by muddy floods—this study examines (a) whether soil erosion and muddy flooding will increase in the future; and (b) whether containing GMTI to 1.5°C would help limit the problem versus 2°C. The Water Erosion Prediction Project model was used to simulate muddy flooding for the present-day and under a range of future scenarios derived from climate models that correspond to 1.5 and 2°C GMTI. The main findings reveal no statistically significant differences between muddy flooding at 1.5 and 2°C GMTI. Limiting GMTI to 1.5°C therefore does not appear to make much difference to soil erosion and muddy flooding, because the timing of changing rainfall intensity does not always follow clear patterns with increased warming. Regardless of the magnitude of future warming, an earlier and longer muddy flooding season is projected—highlighting that mitigation measures should be continually adapted to remain resilient to climate change.