claim: Previous studies have shown that weakening carbon sinks will add 0.25°C, forest dieback will add 0.11°C, permafrost thaw will add 0.9°C and increased bacterial respiration will add 0.02°C.
evidence: A global temperature rise of 1.5 °C ( 2.7 °F ) above current levels would be enough to start the thawing of permafrost in Siberia, according to one group of scientists.