Source Attributions of Radiative Forcing by Regions, Sectors, and Climate Forcers

Understanding the contributions of radiative forcings by different regions, sectors, or climate forcers can help policy-makers understand the relative importance of various sources in terms of meeting the Paris Agreement temperature targets. Here, we used the latest historical and future emissions data for a full suite of climate forcers as well as land-use datasets and applied a normalized marginal approach to quantify the forcing contributions of regions, sectors and forcing agents towards the 2°C and 1.5°C targets. We showed that developing regions, such as China, India, the Middle East and North Africa, sub-Saharan Africa and other areas in Asia, and certain sectors, such as housing and transport, yielded larger forcings in 2100 than at present under the 2°C and 1.5°C scenarios. Our results illustrated the importance of negative CO2 emissions, which contributed - 0.93 ± 0.56 Wm-2 and - 0.52 ± 0.32 Wm-2 to the 2°C and 1.5°C targets, respectively. Less negative forcings or more positive forcings were found for the land-use albedo for the 2°C and 1.5°C scenarios than those reported by earlier studies. Finally, we found that the 2°C and 1.5°C scenarios gave similar patterns of attributed forcings from regions, sectors, and climate forcers at the end of this century.