  It is important to understand how the emissions of different regions,
sectors, or climate forcers play a role on pathways toward the Paris Agreement
temperature targets. There are however methodological challenges for
attributing individual contributions due to complexities associated with a
variety of climate forcers affecting the climate system on different spatial
and temporal scales. Here, we use the latest historical and future emissions
data for a comprehensive set of climate forcers as well as land-use datasets
and apply the normalized marginal approach to quantify the forcing
contributions of regions, sectors and forcing agents toward the 2C and 1.5C
targets. We show that most of the worldwide regions and sectors need to
maintain forcing levels not higher than present levels to attain the 1.5C
target of the Paris Agreement, while slightly higher future forcing levels than
present levels are allowed for the 2C target. Our results illustrate the
importance of negative CO2 emissions, which contribute -0.75+/-0.44 Wm-2 and
-0.42+/-0.27 Wm-2 to the 2C and 1.5C targets. Less negative forcings, or more
positive forcings are also identified for the land-use albedo for the 2C and
1.5C scenarios compared to existing studies.
