Paper Reviewed
Xie, Y., Liu, Y. and Huang, J. 2016. Overestimated Arctic Warming and Underestimated Eurasia Mid-Latitude Warming in CMIP5 Simulations. International Journal of Climatology 36: 4475-4487.

As world leaders consider enacting global warming abatement policies that may well cost trillions of dollars and affect billions of lives, it is important for them to know how the climate models upon which those policies are based align with the real world.

Performing just such an analysis, Xie et al. (2016) analyzed and compared observed features of the Northern Hemisphere's surface air temperature (SAT) from five separate data sets against climate model sumulations derived from 41 Coupled Model Intercomparison Project Phase 5 (CMIP5) models. And what did this comparison reveal?

In describing their findings, Xie et al. (2016) report that (1) model projections of surface air temperature (SAT) trends overestimated warming in high-latitudes while they (2) underestimated warming in mid-latitudes of the Northern Hemisphere. More specifically, they report that (3) "the CMIP5 models did not simulate the enhanced warming over Eurasia," while they (4) "overestimated the warming trend in the coastal areas over the high-latitude regions of Eurasia."

In addition, the three researchers report there is (5) "a discrepancy in meridional temperature gradient (MTG) trends between CMIP5 and observations," even noting that (6) "the observed MTG trend displayed the opposite sign at high latitudes compared with CMIP5 simulations."

Last of all, Xie et al. write that (7) the "defect in the CMIP5 models in simulating internal climate variability may also induce some bias in the Northern Hemisphere mid- and high-latitude surface air temperature trend." Thus, the quest to overcome this vexing problem continues to haunt the climate scientists who seek to resolve it. And that should invoke great pause for those seeking to enact policies designed to address CO2-induced climate change.