World temperature set to reach 1°C marker for first time
Global temperatures are set to reach 1˚C above pre-industrial levels for the first time – according to research from the University of East Anglia and the Met Office.
Limiting warming to no more than 2˚C has become the target for global climate policy.
The 1˚C rise above pre-industrial levels represents a particularly important marker as the world continues to warm due to human influence.
2015 also marks the warmest year since records began, and researchers predict that 2016 may be hotter still.
The HadCRUT dataset, jointly produced by the Climatic Research Unit (CRU) in UEA’s School of Environmental Sciences and the Met Office, shows that the global mean temperature for 2015 so far is 1.02 ˚C (±0.11 ˚C) above pre-industrial levels. This figure is based on data from January to September.
1750 is the era widely assumed to represent pre-industrial conditions, but there is not a reliable indicator of global temperatures dating back this far. The research team used the 1850-1899 global average as an approximation for pre-industrial temperatures because earlier data are less reliable. Relative to a more recent period, 2015 is 0.70°C above the 1961 to 1990 average.
CRU director Prof Phil Jones said: “2015 will clearly be the warmest year since the HadCRUT4 series began in 1850.”
Prof Tim Osborn, also from CRU, added: "We are seeing the combination of two factors that warm the Earth - the continual, ongoing warming of our climate because of increasing greenhouse gases, plus some temporary additional warming this year and next from the El Nino event that is currently heating up the Pacific Ocean."
Prof Jones said: “Looking at the last major El Nino event in 1997/8, 2016 will likely be warmer still, as 2015 is analogous in its increasing warmth through the year to 1997.”
Stephen Belcher, director of the Met Office Hadley Centre, said: “We’ve had similar natural events in the past, yet this is the first time we’re set to reach the 1˚C marker and it’s clear that it is human influence driving our modern climate into uncharted territory.
“Early indications suggest 2016 will be similarly warm and while it’s more difficult to say exactly what will happen in the years immediately after that, we expect warming to continue in the longer term.”
Peter Stott, head of Climate Monitoring and Attribution at the Met Office, said: “This year marks an important first but that doesn’t necessarily mean every year from now on will be a degree or more above pre-industrial levels, as natural variability will still play a role in determining the temperature in any given year.
“As the world continues to warm in the coming decades, however, we will see more and more years passing the 1 degree marker – eventually it will become the norm.”