PCIC science brief: On Paris climate accord emissions and temperature limits
Date
2018-08
Authors
Pacific Climate Impacts Consortium (PCIC)
Journal Title
Journal ISSN
Volume Title
Publisher
Pacific Climate Impacts Consortium (PCIC)
Abstract
The 2015 Paris Climate Accord aims to limit global warming to at most 2 °C and ideally 1.5 °C relative to the preindustrial climate, to limit the impacts of anthropogenic climate change. In this Science Brief, we discuss greenhouse gas emissions budgets and pathways consistent with these warming limits.
Three recent papers in Nature Climate Change examine different aspects of these budgets and pathways: Tokarska and Gillett (2018) use global climate model projections to calculate a new carbon budget for future emissions, relative to the 2006-2015 period, that is consistent with keeping warming to 1.5 °C. They find a median remaining carbon budget of 208 billion tonnes from January 2016. Tanaka and O'Neill (2018) use an integrated assessment model to test whether the Paris temperature limits of 2 °C and 1.5 °C require zero greenhouse gas emissions, whether a zero net greenhouse emissions limit implies that the temperature limits will be met and what the effect of imposing both emissions and temperature limits are. Their results suggest that meeting the temperature limits doesn't require reducing net greenhouse gas emissions to zero, that reducing emissions to zero doesn't necessarily result in keeping temperatures under the Paris temperature limits by the end of the century, and that the effect of imposing both temperature and emissions limits is that temperatures decline after meeting the initial temperature limit.
Van Vuuren et al. also use an integrated assessment model, to develop alternative emissions scenarios that examine how the need for negative emissions may be reduced through implementing other strategies, such as making large-scale lifestyle changes, shifting to renewable energy and switching to more efficient technologies for the production of energy and materials. They find that these strategies can reduce to a small degree, but not eliminate, the need for negative emissions. They also find that these measures have co-benefits such as helping to meet other United Nations sustainability goals.
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Keywords
UN SDG 13: Climate Action, #science brief, Pacific Climate Impacts Consortium (PCIC)