From health impacts to sea level rise, from severe storms to heat and desertification, the last year of scientific research is predicting faster, more severe impacts of climate change than the Intergovernmental Panel on Climate Change (IPCC) was anticipating as recently as three years ago.
“Uncertainty is not our friend here,” Penn State climate scientist Michael Mann told InsideClimate News in a year-end interview. “We are seeing increases in extreme weather events that go well beyond what has been predicted or projected in the past. We’re learning that there are factors we were not previously aware of that may be magnifying the impacts of human-caused climate change.”
Those factors include “subtle mechanisms involving the behaviour of the jet stream that may be involved in explaining the dramatic increase we’ve seen in floods, droughts, heat waves, and wildfires.”
The IPCC’s Fifth Assessment Report, released in 2014, provided the scientific basis for the Paris Agreement, InsideClimate recalls. But more recent major studies from the Royal Society, the American Meteorological Society, and the U.S. National Oceanographic and Atmospheric Administration (NOAA) suggest the IPCC underestimated the risk.
“We have literally, in the space of a year, doubled our assessment of the potential sea level rise we could see by the end of this century,” Mann said. “That is simply remarkable. And it is sobering.”
“It’s a deadly tragedy in the making, all the worse because the same experts are saying such heat waves are eminently survivable with adequate resources to protect people,” said Royal Society lead author Eric Wolff, referring to health impacts that will put millions of vulnerable people around the world at risk.
“The need to build resilience is clear and missing in action,” agreed atmospheric scientist Kevin Trenberth of the U.S. National Center for Atmospheric Research, adding that climate science has progressed in all directions since the IPCC issued its last report. “The result is we suffer the consequences at costs of hundreds of billions of dollars.”
Other major concerns summarized in the Royal Society report include ocean acidification, loss of nutritional value in crops grown in high-carbon dioxide conditions, local water management and food production anomalies, and newly-understood links between Arctic sea ice loss and a variety of weather extremes.
While the Paris agreement sets 2.0°C average global warming as the basic target for average global warming, a study published this week in the journal Nature Climate Change suggests the world will still be a very different place at that level of climate stability.
“Our research predicts that aridification would emerge over about 20 to 30% of the world’s land surface by the time the global mean temperature change reaches 2.0°C,” said report co-author Manoj Joshi of the University of East Anglia. “But two-thirds of the affected regions could avoid significant aridification if warming is limited to 1.5C.”
Principal author Chang-Eui Park of Southern University of Science and Technology in Shenzhen China cited aridification as “a serious threat because it can critically impact areas such as agriculture, water quality, and biodiversity. It can also lead to more droughts and wildfires similar to those seen raging across California.” Southeast Asia, southern Europe, southern Africa, Central America, and southern Australia—home to a combined 20% of the world’s population—would see the greatest benefit of reduced aridification.
While scientific assessments and front-line climate impacts become more severe, there’s still a gap in the news reporting that could help build public consensus for faster, more aggressive action on greenhouse gas emissions, writes Lisa Hymas, director of the climate and energy program at Media Matters for America. Although some news organizations did a particularly good job reporting on some of the year’s climate disasters, “many of the most influential mainstream media outlets need to do better at reporting on the connections scientists are finding between climate change and extreme weather,” she argues.
“When a disaster hits, that’s a prime opportunity to report on climate change, a topic that at other times might not seem newsy. When a long string of unprecedented disasters hit, as happened this year, that’s even more of a call for media to tell the story of global warming.
(h/t to Grist for pointing us to the Nature Climate Change study on desertification risk)