The link between manmade carbon emissions and global warming has been hotly contested, as a lack of research meant scientists couldn’t say that emissions created a specific damage. That link however, has now been measured in various cases, according to a new study.
“The paper is the first to systematically assess regional scale impacts of climate change and their relation to anthropogenic greenhouse gas emissions, introducing a systematic evaluation of confidence levels … through a newly developed algorithm,” said Christian Huggel, a senior researcher from the University of Zurich, who was not involved in the study.
In the report published Monday in Nature Climate Change, researchers Gerrit Hansen and Dáithí Stone found that a connection between recent regional climate trends and manmade climate change, shows that many of the damages on natural and human systems can be attributed to global warming.
Past studies rarely connected impact to greenhouse gas emissions directly, said Stone, a research scientist at the Lawrence Berkeley National Laboratory, in an interview with ThinkProgress. “Linking what’s happening locally to what’s happening globally is something that hadn’t been done in the context of looking at these impacts.”
The year-long study applied computational calculations, or algorithms, onto 118 suspected climate change impacts observed from 1970s to 2010, like coast line erosion, wild fires, ice loss, changes in range of species, and loss of agricultural output from all regions listed in the United Nations Intergovernmental Panel on Climate Change report. Stone said the team found “a confident link that our emissions altogether had been an important contributor to the trends in at least two thirds of the cases,”
These results confirm widely believed notions in the scientific community that manmade climate change is damaging natural systems worldwide. According to the study, the frozen water areas of the planet and marine systems showed the highest share of impact cases, with at least medium confidence, to manmade emissions. Most effects linked to manmade climate change held at least a medium confidence level, although higher confidence levels were recorded too.
In the United States, the study links wildfires in the Alaska area, droughts in the west coast and effects to glaciers — to name a few — to manmade climate change.
As far as the remaining one third of cases that researchers couldn’t link to emissions, Stone said that many times data wasn’t available. Hence, the algorithm couldn’t be confidently applied. “We didn’t have observations of what was happening, so we couldn’t actually, we don’t know what’s been happening there.”
Data is mainly missing from Africa, particularly central Africa, said Stone. It is widely believed that areas in the southern hemisphere, those that the research couldn’t confidently measure, are the ones that could be affected the most as global warming continues.
The study also found that changes in precipitation couldn’t for the most part, be attributed to emissions. Stone explained that wasn’t the case as far as the Artic, where ice melting and warming temperature make a make “a big difference to precipitation and that’s been documented.”
But while the study is a major bridge between emissions, global warming, and its effects,Stone conceded that their study didn’t cover all impacts and that much more monitoring is needed. Still, he said the study adds to the body of evidence of manmade climate change. “As to whether it will change minds, I’m not sure I’m the one to ask about that,” he said.
Changing minds is essential for climate action, especially in the United States, a major emitter of global warming gases, that is also deeply divided on how aggressively it should act on manmade climate change. The divide is so drastic that no Republican running for president accept mainstream climate science, or backs the Paris climate agreement reached to curb global warming.
That’s despite a Reuters poll released Tuesday found that more than half, or 58 percent or Republicans surveyed approved U.S. efforts to work with other nations to alleviate global warming. Moreover, 40 percent said they would back a presidential candidate that did so.