Institutional “Paris Agreement Compatible” Mitigation Scenarios Evaluated Against the Paris Agreement 1.5°C Goal

Abstract

Since its adoption in 2015, governments, international agencies and private entities have increasingly recognized the implications of the Paris Agreement’s 1.5°C long-term temperature goal (LTTG) for greenhouse gas emissions reduction planning in both the near- and long-term. Governments have submitted or are preparing updates of their Nationally Determined Contributions (NDCs) and are encouraged to submit long term low greenhouse gas development plans (Article 4 of the Agreement1), aimed at aligning short- and long-term strategies. The foundations on which country targets are based are guided, directly or indirectly, by a variety of sources of information judged to be authoritative, including scientific research institutes2, international agencies, or private companies. Importantly, such authoritative sources also affect planning and decision making by investors3 who aim to anticipate climate policies, and their decisions in turn can drive or hold back setting ambitious emissions-reduction targets.

An emission pathway classification reflecting the Paris Agreement climate objectives

“…Pathways belonging to the C1 category limit warming to 1.5 °C in 2100 with a greater than 50% chance and hold warming below 1.5 °C throughout the 21 st century with at least a 34% chance. This category of pathways have been used to identify pathways that are consistent with the Paris Agreement temperature goal 26,37 . We further proceed to classify these low and no overshoot pathways according to their consistency with an alternative, plausible interpretation of Article 2.1, and Article 4 of the Paris Agreement, that we lay out in this paper.…”