An investigation into linearity with cumulative emissions of the climate and carbon cycle response in HadCM3LC

Liddicoat, S.K., Booth, B.B.B. and Joshi, M.M. (2016) An investigation into linearity with cumulative emissions of the climate and carbon cycle response in HadCM3LC. Environmental Research Letters, 11 (6). ISSN 1748-9326

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    Abstract

    We investigate the extent to which global mean temperature, precipitation, and the carbon cycle are constrained by cumulative carbon emissions throughout four experiments with a fully coupled climate-carbon cycle model. The two paired experiments adopt contrasting, idealised approaches to climate change mitigation at different action points this century, with total emissions exceeding two trillion tonnes of carbon in the later pair. Their initially diverging cumulative emissions trajectories cross after several decades, before diverging again. We find that their global mean temperatures are, to first order, linear with cumulative emissions, though regional differences in temperature of up to 1.5K exist when cumulative emissions of each pair coincide. Interestingly, although the oceanic precipitation response scales with cumulative emissions, the global precipitation response does not, due to a decrease in precipitation over land above cumulative emissions of around one trillion tonnes of carbon (TtC). Most carbon fluxes and stores are less well constrained by cumulative emissions as they reach two trillion tonnes. The opposing mitigation approaches have different consequences for the Amazon rainforest, which affects the linearity with which the carbon cycle responds to cumulative emissions. Averaged over the two fixed-emissions experiments, the transient response to cumulative carbon emissions (TCRE) is 1.95 K TtC-1, at the upper end of the IPCC’s range of 0.8-2.5 K TtC-1.

    Item Type: Article
    Additional Information: Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
    Faculty \ School: Faculty of Science > School of Environmental Sciences
    Depositing User: Pure Connector
    Date Deposited: 18 May 2016 14:00
    Last Modified: 09 Apr 2019 11:13
    URI: https://ueaeprints.uea.ac.uk/id/eprint/58865
    DOI: 10.1088/1748-9326/11/6/065003

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