Don't panic: runaway global warming study 'very implausible'
The apocalyptic predictions of runaway global warming from 2150 in an international climate study must be taken with a grain of salt, Kiwi researchers warn. The new research, published in the journal Scientific Reports , predicts that decades after humans bid adieu to fossil fuels, the climate could enter a vicious cycle of self-perpetuating warming. The only human-made solution is pulling massive amounts of carbon out of the air and storing it, the authors conclude. The model used to make these dire predictions is a simple one, the researchers admit. The state-of-the-art ones, such as those used by the Intergovernmental Panel on Climate Change (IPCC), arent coming to the same conclusions, said University of Canterbury climate researcher Laura Revell. These state-of-art climate models are highly complex, she said. We have [one] installed on supercomputers here in New Zealand and it still takes a couple of months to run a 100-year simulation. In comparison, less complex models such as the one in the study can run on a desktop computer in a few seconds, she said. Its just one model and its a very simple model. READ MORE: * Kiwi research bolstered Paris Agreement's climate goals * Global warming predicted forty years ago, anniversary * James Renwick: One simple thing you can do to tackle climate change The just-released study outlined the basic models projections of how melting polar ice, water vapour and the methane trapped in frozen land would influence each other, out to the year 2500. The Norwegian researchers believe the world will reach peak greenhouse emissions by 2030 and will only achieve zero-carbon by 2100 thereby missing our goal to limit global warming to 1.5 degrees Celsius . If that plays out, their model projects that global temperatures will reach a peak around 2075, fall slightly, then start to climb again from 2150. This prediction relies on a continual loss of polar ice between now and 2500. The ice plays a key role in keeping our planets climate stable being white, it bounces sunlight back into space. The darker ocean waters absorb much more heat. From there, humidity rises and frozen tundra landscapes (or permafrost) near the poles thaw . Both of these would increase global temperatures in a self-perpetuating cycle, even without human-generated emissions. Notably, the model also predicts a similar vicious cycle would occur even if we cut all greenhouse emissions today. However, the most robust predictions of the climate our great-grandchildren will face will be made public next year when the IPCC is expected to release its latest report , Revell said. Thats when the state-of-the-art Earth system models get run into the future under different greenhouse gas scenarios. Revell discourages any panic about the new studys predictions. I dont really buy into the doom and gloom from this study. She also disagrees with the idea that, past a certain point, climate action becomes useless. Any positive action we take today will have a positive implication for us in the future... Theres never any point in giving up. Victoria University climate scientist James Renwick agrees that the findings are out of step with other projections. The results presented in this paper are very implausible and should not be seen as cause for alarm. If the world successfully limits global warming to under 2C, the scientific consensus suggests well see some impacts. But there is no sign of any form of runaway climate change. In the study, the researchers use their predictions to stress the need for global action. Research co-author Jorgen Randers said humanity must do two things: rapidly decarbonise, plus capture and store truly vast amounts of carbon from the air. The model suggests wed need to suck at least 33 gigatonnes thats 33 billion tonnes of carbon dioxide out of the atmosphere each year. Randers invites other researchers with access to complex climate models to test the study predictions, noting: Their models are much bigger than ours, and may reveal counteracting forces that can stop the melting we observe. Randers agreed people shouldnt lose hope. We should cut the use of fossil fuels as fast as possible and start preparing for large-scale capture of carbon dioxide from the atmosphere.