Science Source

Probabilistic estimates of recent changes in temperature: a multi-scale attribution analysis

Investigates the role of anthropogenic forcings in temperature changes during recent decades over a range of spatial scales
Considers changes in the annual mean surface temperature and also in the warmest night of the year, which has implications for human health
Produces distributions of regional trends with and without the effect of human activity using constraints from a global optimal detection analysis
Estimates anthropogenic forcings to have more than doubled the likelihood of mean warming in all regions considered except central North America, where results are more model dependent
Finds the likelihood of warming of the warmest night has also increased, but the estimated change is more uncertain
Inferences on sub-continental scales are indicative rather than definitive because of the absence of locally important forcings and processes in model simulations, as well as model biases
Concludes that a multi-model approach is essential as model inconsistencies may impact regional analyses