A modified impulse-response representation of the global near-surface air temperature and atmospheric concentration response to carbon dioxide emissions

• Published in: Atmospheric chemistry and physics 2017-06, Vol.17 (11), p.7213-7228
• Main Authors: Millar, Richard J, Nicholls, Zebedee R, Friedlingstein, Pierre, Allen, Myles R
• Format: Article
• Language: English
• Subjects: Accessibility; Air pollution; Air temperature; Anthropogenic factors; Atmosphere; Atmospheric carbon dioxide; Atmospheric circulation; Atmospheric models; Atmospheric temperature; Carbon; Carbon dioxide; Carbon dioxide atmospheric concentrations; Carbon dioxide concentration; Carbon dioxide emissions; Carbon monoxide; Carbon uptake; Climate; Climate change; Climate system; Complexity; Earth; Earth atmosphere; Emission analysis; Emissions; Environmental aspects; Environmental assessment; Environmental policy; Estimates; Evaluation; Experiments; Geoengineering; Global temperatures; Greenhouse effect; Greenhouse gases; Intergovernmental Panel on Climate Change; Links; Observations; Representations; Surface temperature; Surface-air temperature relationships; Temperature changes; Temperature effects; Temperature requirements; Uptake
• ISSN: 1680-7324; 1680-7316; 1680-7324
• DOI: 10.5194/acp-17-7213-2017

Projections of the response to anthropogenic emission scenarios, evaluation of some greenhouse gas metrics, and estimates of the social cost of carbon often require a simple model that links emissions of carbon dioxide (CO2) to atmospheric concentrations and global temperature changes. An essential requirement of such a model is to reproduce typical global surface temperature and atmospheric CO2 responses displayed by more complex Earth system models (ESMs) under a range of emission scenarios, as well as an ability to sample the range of ESM response in a transparent, accessible and reproducible form. Here we adapt the simple model of the Intergovernmental Panel on Climate Change 5th Assessment Report (IPCC AR5) to explicitly represent the state dependence of the CO2 airborne fraction. Our adapted model (FAIR) reproduces the range of behaviour shown in full and intermediate complexity ESMs under several idealised carbon pulse and exponential concentration increase experiments. We find that the inclusion of a linear increase in 100-year integrated airborne fraction with cumulative carbon uptake and global temperature change substantially improves the representation of the response of the climate system to CO2 on a range of timescales and under a range of experimental designs.