What Would it Take to Achieve the Paris Temperature Targets?
The 2015 Paris Agreement aims to limit warming to 2 or 1.5C above pre-industrial levels, although combined Intended Nationally Determined Contributions (INDCs) are likely insufficient to achieve these targets.
We propose a set of idealized emissions pathways consistent with the targets. If countries reduce emissions in line with their INDCs, the 2C threshold could be avoided only if net zero greenhouse gas emissions (GHGEs) are achieved by 2085 and late century negative emissions are considerably in excess of those assumed in RCP2.6 (net -5 GtCO2/yr, compared with -1.5 GtCO2/yr in RCP2.6). More aggressive near-term reductions would allow 2C to be avoided with less end-of-century carbon removal capacity.
Computing time has been secured to create follow-ups for NCAR's large ensemble, using the emissions pathways defined in this paper, to produce simulations which can inform the upcoming IPCC special report on 1.5 degrees.