Details

Autor(en) / Beteiligte

• Joos, F
• Roth, R
• Fuglestvedt, J. S
• Peters, G. P
• Enting, I. G
• von Bloh, W
• Brovkin, V
• Burke, E. J
• Eby, M
• Edwards, N. R
• Friedrich, T
• Frölicher, T. L
• Halloran, P. R
• Holden, P. B
• Jones, C
• Kleinen, T
• Mackenzie, F. T
• Matsumoto, K
• Meinshausen, M
• Plattner, G.-K
• Reisinger, A
• Segschneider, J
• Shaffer, G
• Steinacher, M
• Strassmann, K
• Tanaka, K
• Timmermann, A
• Weaver, A. J

Titel

Carbon dioxide and climate impulse response functions for the computation of greenhouse gas metrics: a multi-model analysis

Ist Teil von

• Atmospheric chemistry and physics, 2013-03, Vol.13 (5), p.2793-2825

Ort / Verlag

Katlenburg-Lindau: Copernicus GmbH

Erscheinungsjahr

2013

Quelle

Electronic Journals Library

Beschreibungen/Notizen

• The responses of carbon dioxide (CO sub(2)) and other climate variables to an emission pulse of CO sub(2) into the atmosphere are often used to compute the Global Warming Potential (GWP) and Global Temperature change Potential (GTP), to characterize the response timescales of Earth System models, and to build reduced-form models. In this carbon cycle-climate model intercomparison project, which spans the full model hierarchy, we quantify responses to emission pulses of different magnitudes injected under different conditions. The CO sub(2) response shows the known rapid decline in the first few decades followed by a millennium-scale tail. For a 100 Gt-C emission pulse added to a constant CO sub(2) concentration of 389 ppm, 25 plus or minus 9% is still found in the atmosphere after 1000 yr; the ocean has absorbed 59 plus or minus 12% and the land the remainder (16 plus or minus 14%). The response in global mean surface air temperature is an increase by 0.20 plus or minus 0.12 degree C within the first twenty years; thereafter and until year 1000, temperature decreases only slightly, whereas ocean heat content and sea level continue to rise. Our best estimate for the Absolute Global Warming Potential, given by the time-integrated response in CO sub(2) at year 100 multiplied by its radiative efficiency, is 92.5 x 10 super(-15) yr W m super(-2) per kg-CO sub(2). This value very likely (5 to 95% confidence) lies within the range of (68 to 117) x 10 super(-15) yr W m super(-2) per kg-CO sub(2). Estimates for time-integrated response in CO sub(2) published in the IPCC First, Second, and Fourth Assessment and our multi-model best estimate all agree within 15% during the first 100 yr. The integrated CO sub(2) response, normalized by the pulse size, is lower for pre-industrial conditions, compared to present day, and lower for smaller pulses than larger pulses. In contrast, the response in temperature, sea level and ocean heat content is less sensitive to these choices. Although, choices in pulse size, background concentration, and model lead to uncertainties, the most important and subjective choice to determine AGWP of CO sub(2) and GWP is the time horizon.