Earth is warming faster than we thought, Met Office says 

The world is warming faster than previously thought, the Met Office has found, after improving its measures in the Arctic and oceans.

There has been 18 per cent more warming since the second half of the 19th century than previous analysis suggested, scientists said.

The fifth version of the HadCRUT dataset, developed alongside the University of East Anglia, measures global temperatures stretching back to 1850.

The new analysis suggests that the average global temperature for 2010-2018 was 1.07 degrees warmer than average conditions in 1850-1900, 0.16 degrees more than in the previous version of the data set.

Co-author Tim Osborn, professor of climate science at the University of East Anglia, said the higher estimate was because of better data from the oceans and Arctic, which is believed to be warming more quickly than other parts of the world.

"Climate change has not suddenly got worse: instead, we have an improved estimate of how much warming has taken place," he said.

The paper, published in the Journal of Geophysical Research: Atmospheres, takes data from sensors on land and sea around the world, amalgamating them into a global picture.

The update comes from two major changes to the way the scientists interpreted the data. One of these centred around the way water temperatures were taken at sea, and better calibration between data taken from sensors on buoys and by crews on ships.

Scientists from the Met Office looked at the best-quality data collected on buoys and scientific research ships and compared it to other methods.

Sea water temperature measurements were historically taken by ships using buckets brought up to their engine rooms, but during the 1970s and 80s water pumped from the sea to cool the ship's engine was increasingly measured.

Moving through pipes warmed the water up, and recent research suggests this effect was stronger than was previously realised, so the analysis was revised to show cooler averages, suggesting a sharper rise in sea temperatures over the past 40 years.

The other area of change was the way temperatures in the Arctic were taken. Previously if an area did not have a sensor in it it was left out of the estimate, but now the data uses readings from adjacent areas instead, meaning the Arctic has greater weight.

Other scientists not involved in the research said that the revision brought the study in line with other datasets also measuring global warming.

"Because quite a lot of those missing squares are in the Arctic, which has been warming two to three times faster than the average for the globe, that meant we were not sampling fully some of the regions that were warming the fastest," added Professor Osborn.  

"Some of the other global temperature datasets showed more warming than previous versions, and now we're more closely aligned with those."

Professor Ed Hawkins, a climate research scientist at the University of Reading, said: "HadCRUT5 shows more historical warming than the previous version of the dataset which makes it more consistent with other datasets produced by different groups around the world.  

"The planet is warming and this is yet another reminder that restricting global warming to the levels specified in the Paris Agreement will require rapid and deep cuts to our greenhouse gas emissions.”

The team made its first estimate in 1986 and its estimates currently cover the time up to 2018, with 2020 set to be added when figures for the whole year become available.

Lead author Dr Colin Morice, of the Met Office, said that the figures were consistent with other studies by groups including Nasa and US agency the National Oceanic and Atmospheric Administration, despite being produced using different methods.

"The range of approaches results in very similar estimates of overall warming and provides scientific confidence in the changes seen and also reinforces the fact that the world has warmed considerably since the mid nineteenth century," he said.