Table 2.
This study* | Sellers et al. (1996) | Betts et al. (1997) | Cox et al. (1999) | Betts et al. (2007) | Boucher et al. (2009)† | |
Evapotranspiration over land (mm day-1) | −0.054 ± 0.004 | −0.045 | −0.07 | −0.04 | ||
Surface air temperature over land (K) | 0.47 ± 0.04 | 0.3 | 0.2 | 0.39 | 0.52 | |
Fractional contribution of surface warming over land from CO2-physiological forcing‡ | 16.4 ± 0.7% | 10.7% | 11.3% | 12.9% | ||
Runoff (mm day-1) | 0.082 ± 0.005 | 0.04 | 0.04 | 0.03 | ||
Fractional contribution of runoff increase from CO2-physiological forcing‡ | 65.2 ± 11% | 57.1% | 37.2% | 27.3% | ||
Precipitation over land (mm day-1) | 0.028 ± 0.01 | −0.01 | −0.02 | −0.03 | 0.01 | −0.01 |
*To be consistent with the method used in other studies, the CO2-physiological effect shown here is calculated from the difference between the results of RAD + PHYS - CTR and RAD - CTR listed in Table 1.
†The CO2-physiological effect reported by Boucher et al. (10) was calculated from the transient simulations under the IS92a emission scenario, which have a CO2 increase somewhat more than a doubling.
‡The fractional contribution of changes in temperature and runoff due to CO2-physiological forcing is calculated as the ratio between changes in temperature and runoff in response to CO2-physiological forcing and their changes in response to the combined effect of CO2-radiative and physiological forcing.