Slowdown of global surface air temperature increase and acceleration of ice melting

Abstract

AbstractAlthough recent decades have been the warmest since 1850, and global mean temperatures during 2015 and 2016 beat all instrumental records, the rate of increase in global surface air temperature (GSAT) significantly decreased at the beginning of the 21st Century. In this context, we examine the roles of ice melting and associated increase in sea‐water mass, both of which significantly increased at the same time as GSAT decreased. Specifically, we show that (1) the slowdown of the rate of increase in GSAT between the specific periods 1992–2001 and 2002–2011 exists in all three climate records analyzed and is statistically significant at the 5% level amounting between 0.029 and 0. 036°C/yr and leaving an energy of 14.8–18.4 1019 J/yr available; (2) the increase of the atmosphere‐related ice melt between these two periods amounts to 316 Gt/yr which requires 10.5 1019 J/yr, that is, between 57% and 71% of the energy left by the slowdown; and (3) the energy budget shows, therefore, that the heat required to melt this additional 316 Gt/yr of ice is of the same order as the energy needed to warm the atmosphere during the decade 2002–2011 as much as during the previous one, suggesting a redistribution of heat within the atmosphere–cryosphere system.