From Geoff Harding, Sydney, Australia
In your look at whether climate change is accelerating after a record year of heat, you cite models that predict a speeding up due to underestimates of the loss of the cooling effect of some pollutants. These are in decline as clean air policies take hold (11 May, p 14).
The contribution of wind doesn’t seem to have been fully accounted for either. The IPCC predicts that as the planet warms, average wind speeds will fall due to lower temperature gradients. Lower wind speeds have possibly contributed to the recent record high ocean temperatures, because of a reduction in the cooling of the waters due to wind-induced evaporation. Slower winds also result in lower infrared emissivity of the ocean surface, which would reduce heat loss by radiation.
