A new analysis of the scientific and policy aspects of the 1.5°C temperature limit in the Paris Agreement’s long-term temperature goal has identified a number of important areas that require more scientific research. The analysis, written by a team of scientists who have published key research papers on the science, impacts and policy aspects of the 1.5˚C limit, is a centrepiece of a collection by Nature Climate Change, Nature Geoscience and Nature on 'Targeting 1.5°C'  

Short summary of the 10 key messages from the final report of the Structured Expert Dialogue  

A new study analyses the differences in impacts the world would face at 1.5°C and 2°C in a comprehensive and comparable way for the first time. It finds that the increases in impacts between 1.5°C and 2°C are large, significant and pronounced for regions with limited adaptive capacity and high exposure.  

This document provides briefing points and explains why initial and successive 5 year commitment periods for all Parties are a necessary element of the new agreement to help ensure that the 1.5/2°C goal is met, and how a 10-year commitment period would in fact fail to provide the long-term stability and certainty that Parties seek. It steps through evidence from scientific, economic, regulatory and political perspectives.  

This document provides key points on risks to ecosystems, food security and sustainable development associated with 1.5°C warming. It also provides responses to arguments commonly made against 1.5°C and provides the scientific evidene for each point made.  

This briefing note outlines the scientific conditions under which warming can be limited to well below 2°C over the 21st century, and return to below 1.5°C by 2100. It provides a scientific overview of the science on some critical mitigation technologies, like bioenergy, carbon capture and storage, and their combination – BECCS. It also contains counter arguments to claims that 1.5°C scenarios undermine food security through including large scale bioenergy deployment. The considerations in this briefing are based on the findings of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5), the 2014 UNEP Emissions Gap Report, the Report of the UNFCCC Structured Expert Dialogue (SED), as well as the recent scientific literature.  

Robust appraisals of climate impacts at different levels of global-mean temperature increase are vital to guide assessments of dangerous anthropogenic interference with the climate system. The 2015 Paris Agreement includes a two-headed temperature goal: “holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C. This paper provides an assessment of key impacts of climate change at warming levels of 1.5°C and 2°C, including extreme weather events, water availability, agricultural yields, sea-level rise and risk of coral reef loss- The results reveal substantial differences in impacts between a 1.5°C and 2°C warming that are highly relevant for the assessment of dangerous anthropogenic interference with the climate system. This article has been accepted.