t says that the average temperature is likely to rise by 0.43 C by 2017 - as opposed to an earlier forecast that suggested a warming of 0.54C. The explanation is that a new kind of computer model using different parameters has been used. The Met Office stresses that the work is experimental and that it still stands by its longer-term projections.
These forecast significant warming over the course of this century. The forecasts are all based on a comparison with the average global temperature over the period 1971-2000. The earlier model had projected that the period 2012-16 would be 0.54C above that long-term average - within a range of uncertainty from 0.36-0.72C. By contrast the new model, known as HadGEM3, gives a rise about one-fifth lower than that of 0.43C - within a range of 0.28-0.59.
This would be only slightly higher that the record year of 1998 - in which the Pacific Ocean's El Nino effect was thought to have added more warming. If the forecast is accurate, the result would be that the global average temperature would have remained relatively static for about two decades.