Identifying crucial emission sources under low forcing scenarios by a comprehensive attribution analysis

Clarifying the contributions of radiative forcings from different regions, sectors, and climate forcers can help policymakers understand the relative importance of various sources for meeting the Paris Agreement temperature targets. Here, we show a comprehensive study using a normalized marginal method to quantify such forcing contributions under scenarios toward the low forcing levels of 1.9 and 2.6 Wm−2 in 2100, proxies of the 1.5°C and 2°C targets of the Paris Agreement, respectively. We found that the distribution of forcing contributions appears to be similar between the present and 2100 by region, though it differs substantially by sector and climate forcer. Most developing regions and housing and transport sectors yield larger forcings in 2100 than at present under low forcing scenarios. Achieving low forcing levels strongly relies on negative CO2 emissions under the scenarios we considered. Finally, our results indicate a crucial role for China in reducing end-of-the-century forcing contributions from high to low levels.