New climate predictions assess global temperatures

The annual mean global temperature is likely to be at least 1° Celsius above pre-industrial levels (1850-1900) in each of the coming five years (2020-2024) and there is a 20per cent chance that it will exceed 1.5°C in at least one year, according to new climate predictions issued by the World Meteorological Organization (WMO).

The Global Annual to Decadal Climate Update, led by the United Kingdom’s Met Office, provides a climate outlook for the next five years, updated annually. It harnesses the expertise of internationally acclaimed climate scientists and the best computer models from leading climate centres around the world to produce actionable information for decision-makers.

The earth’s average temperature is already over 1.0 C above the pre-industrial period. The last five-year period has been the warmest five years on record. 

“This study shows – with a high level of scientific skill – the enormous challenge ahead in meeting the Paris Agreement on Climate Change target of keeping a global temperature rise this century well below 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius,” said WMO Secretary-General Petteri Taalas.

The predictions take into account natural variations as well as human influences on climate to provide the best possible forecasts of temperature, rainfall, wind patterns and other variables for the coming five years. The forecast models do not take into consideration changes in emissions of greenhouse gases and aerosols as a result of the coronavirus lockdown.

“WMO has repeatedly stressed that the industrial and economic slowdown from COVID-19 is not a substitute for sustained and coordinated climate action. Due to the very long lifetime of CO2 in the atmosphere, the impact of the drop in emissions this year is not expected to lead to a reduction of CO2 atmospheric concentrations which are driving global temperature increases,” said Professor Taalas.

“Failure to tackle climate change may threaten human well-being, ecosystems and economies, governments should use the opportunity to embrace climate action as part of recovery programmes,” he said.

Professor Adam Scaife is the head of long-range prediction at the Met Office Hadley Centre. He said: “This is an exciting new scientific capability.  As human-induced climate change grows, it is becoming even more important for governments and decision makers to understand the current climate risks on an annually-updated basis.”

According to the study, annual global temperature is likely to be at least 1°C warmer than preindustrial levels (defined as the 1850-1900 average) in each of the coming five years and is very likely to be within the range 0.91 – 1.59°C; there is a ~70per cent chance that one or more months during the next 5 years will be at least 1.5°C warmer than preindustrial levels.

There is a ~20per cent chance that one of the next five years will be at least 1.5°C warmer than preindustrial levels, but the chance is increasing with time. It is extremely unlikely (~3per cent) that the five year mean temperature for 2020-2024 will be 1.5°C warmer than preindustrial levels.