3 ms·

The temperature impulse response of CO2 does not seem to have a half-life of 27 years if you look at page 711 of the IPCC report. https://www.ipcc.ch/site/ass

• mirimir 8y ago
  Yes, and on page 712: > Figure 8.29 Development of AGWP-CO2, AGWP-CH4 and GWP-CH4 with time horizon. The yellow and blue curves show how the AGWPs changes with increasing time horizon. Because of the integrative nature the AGWP for CH4 (yellow curve) reaches a constant level after about five decades. The AGWP for CO2 continues to increase for centuries. Thus the ratio which is the GWP (black curve) falls with increasing time horizon. That is, CO2 greenhouse forcing continues for centuries. Back when I worked on this stuff, we used an approximate half life of 250 years. But it's really more complicated. That IPCC report says this, on page 737: > No single lifetime can be given [for CO2]. The impulse response function for CO2 from Joos et al. (2013) has been used. See also Supplementary Material Section 8.SM.11. From Joos et al. (2013):[0] > The CO2 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 CO2 concentration of 389 ppm, 25±9 % is still found in the atmosphere after 1000 yr; the ocean has absorbed 59±12 % and the land the remainder (16±14 %). 0) https://www.atmos-chem-phys.net/13/2793/2013/acp-13-2793-2013.pdf https://www.atmos-chem-phys.net/13/2793/2013/acp-13-2793-201...