An emission pathway classification reflecting the Paris Agreement climate objectives

Greenhouse gas emissions pathways compatible with the Paris Agreement simultaneously pursue warming of less than 1.5 degrees C, very likely never exceed 2 degrees C and achieve net zero greenhouse gas emissions by the second half of the century. They can require smaller amounts of carbon dioxide removal. The 2015 Paris Agreement sets the objectives of global climate ambition as expressed in its long-term temperature goal and mitigation goal. The scientific community has explored the characteristics of greenhouse gas emission reduction pathways in line with the Paris Agreement. However, when categorizing such pathways, the focus has been put on the temperature outcome and not on emission reduction objectives. Here we propose a pathway classification that aims to comprehensively reflect the climate criteria set out in the Paris Agreement. We show how such an approach allows for a fully consistent interpretation of the Agreement. For Paris Agreement compatible pathways, we report net zero CO2 and greenhouse gas emissions around 2050 and 2065, respectively. We illustrate how pathway design criteria not rooted in the Paris Agreement, such as the 2100 temperature level, result in scenario outcomes wherein about 6 - 24% higher deployment (interquartile range) of carbon dioxide removal is observed.

Automated summary

Research on pathway classification that comprehensively reflects the climate criteria set out in the Paris Agreement provides detailed explanations for achieving greenhouse gas emission reduction goals and emphasizes the importance of pathway design consistent with the agreement.