- Long-range forecasts are unlike weather forecasts for the next few days
- Forecasts show the likelihood of a range of possible outcomes
- The most likely outcome in the forecast will not always happen
- Forecasts are for average conditions over a wide region and time period
- For more details on interpretation, see How to use our long-range predictions
Issued 2 December 2010.
Near record temperatures in 2010 to be followed by cooler 2011
Although La Niña has stabilised, it is still expected to affect global temperature through the coming year. This effect is small compared to the total accrued global warming to date, but it does mean that 2011 is unlikely to be a record year according to the Met Office prediction based on the three main data sets. Nevertheless an anomaly of 0.44 °C is still likely - with the range very likely to be between 0.28 °C and 0.60 °C. The middle of this range would place 2011 among the top-10 warmest years on the record.
Dr Vicky Pope, the Met Office's head of climate science advice, said: "Our annual prediction of global temperatures for the next year combined with our monitoring of the observed climate helps people to put the world's current climate into context."
- The 1961-90 global average mean temperature is 14.0 °C.
- Interannual variations of global surface temperature are strongly affected by the warming influences of El Niño and the cooling influences of La Niña in the Pacific Ocean. These are quite small when compared to the total global warming since 1900 of about 0.8 °C but nevertheless typically reach about ±0.10 °C, and can strongly influence individual years.
- For the 2011 forecast the Met Office has used the Met Office and University of East Anglia surface temperature record over the global land and the global oceans (Met Office - CRU) along with those maintained by the NOAA National Climatic Data Center and the NASA Goddard Institute of Space Studies, both in the United States. All three records were used in the latest report of the Intergovernmental Panel on Climate Change.
- The Met Office prediction for 2011 combines information from our dynamical models and statistical information. The forecast takes into account known contributing factors, such as El Niño and La Niña, increasing greenhouse gas concentrations, the cooling influences of industrial aerosol particles, solar effects, volcanic cooling effects if known, and natural variations of the oceans. No significant volcanic effects are currently expected in 2011.
Verification of Annual Forecasts
- These annual forecasts are provided as a probability range. In order to verify them it is necessary to look at as many forecasts as possible to provide a proper statistical analysis. The forecasts issued since 2000 have been successful in capturing the observed records within the predicted range - see Fig 1
- Over the last 10 years there has been a small tendency for the Met Office - CRU data to be in the lower half of the predicted range of temperatures. It would appear that the limited number of observations in the Arctic may have led to this tendency.
- The limited surface observations that we have (together with Satellite observations) show that the Arctic is warming faster than other parts of the globe. Fig 3 shows that the data coverage has decreased between the 1990s and 2000s Some observational estimates take more account of the Arctic warming than Met Office - CRU, hence the need to compare our global forecast temperatures to the range of global records.
- If we restrict our predictions to cover the region between 60°N and 60°S (Fig. 2) and compare them with the three observational data sets from 60°N to 60°S over the last 10 years, the predictions lie on average near the centre of the observational estimates.
Annual forecasts and hindcasts, global.
Figure 1: Anomaly from 1961-1990 average.
Annual forecasts and hindcasts, between 60°N and 60°S.
Figure 2: Anomaly from 1961-1990 average between 60°N and 60°S.
Fig.1 and 2: Annual forecasts from 2000 are shown as a white line with 95% uncertainty range in purple, and hindcasts are shown as a white line with the 95% uncertainty range in turquoise. Observational data sets (Met Office - CRU version HadCRUT3, NASA GISS and NOAA NCDC) are black and grey. (Fig 1) Globe, (Fig 2) 60S to 60N. Note that the three data sets agree extremely well for 60N to 60S where there is more complete data.
Coverage of land surface temperature data
Figure 3: The difference in coverage of land surface temperature data between 1990-1999 and 2005-2010. Blue squares are common coverage. Orange squares are areas where we had data in the 90s but don't have now and the few pale green areas are those where we have data now, but didn't in the 90s. The largest difference is over Canada.
Last Updated: 15 August 2011