Global mean temperature at Earth’s surface to reach 1C above pre-industrial levels for the first time

Global mean temperature at the Earth’s surface is set to reach 1°C above pre-industrial levels for the first time, according to data from the Met Office, a weather and climate services provider based in the United Kingdom.

Year-to-date (January to September) 2015 data from the hadCRUT dataset – jointly run by the Met Office and the Climate Research Unit at the University of East Anglia in Norwich, England – shows 2015 global mean temperature at 1.02 °C (±0.11 °C) above pre-industrial levels, the Met Office said in a release on Monday.

“This represents an important marker as the world continues to warm due to human influence,” the release said.

Stephen Belcher, director of the Met Office Hadley Centre, said some of the impact on this year’s global temperature could be attributed to the strong El Nino development in the Tropical Pacific. “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,” Belcher said.

Early indications suggest that 2016 will be similarly warm and while it’s more difficult to say exactly what will happen in the years immediately after that, the Met Office said it expects “warming to continue in the longer term.” [click image below to enlarge]

Peter Stott, head of climate monitoring and attribution, acknowledged that 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.” He said that “as the world continues to warm in the coming decades, however, we will see more and more years passing the one degree marker – eventually it will become the norm.”

While temperatures this year are around halfway to 2°C, indicators of current and future change are at different stages due to the time it takes for greenhouse gases to influence the climate system. Cumulative emissions of carbon dioxide (CO2) will be key to determining the amount of eventual global warming. It’s estimated that up to 2,900 Gigatonnes of CO2 (GtCO2) can be emitted to have a likely (more than 66%) chance of limiting warming to below 2 °C.

As of 2014, about 2,000 GtCO2 had already been emitted, meaning society has used about two thirds of the 2°C budget, giving an indication that there is already a commitment to “some level of further warming,” the release noted.

Despite this further warming, research suggests it is still possible to limit warming to 2°C above pre-industrial levels, the Met Office reported. However, the later that global CO2 emissions peak, the faster subsequent emissions cuts would need to be in order to keep global temperature rise below the limit.