Climate change may be progressing incrementally, but one of those increments is sure to produce abrupt, possibly irreversible changes, a new report says.
Citing mass polar ice melt, ocean dead zones and the potential for mass extinction across plant and animal species, the National Research Council has issued a report warning of what might happen in the near future, what will take longer, and phenomena whose timing is unclear.
One thing is clear: We do not know what we are messing with.
"Research has helped us begin to distinguish more imminent threats from those that are less likely to happen this century," said James W.C. White, professor of geological sciences at the University of Colorado, Boulder, and chair of the committee that wrote the report, in a statement from the council. "Evaluating climate changes and impacts in terms of their potential magnitude and the likelihood they will occur will help policymakers and communities make informed decisions about how to prepare for or adapt to them."
The report puts many aspects of climate change in perspective and gives something of a timetable for when major changes might occur, so as to facilitate planning. For instance a massive methane release from melting permafrost, while worrisome, will most likely not happen this century, the statement said. Neither will a shutdown in the Atlantic Ocean circulation patterns, the researchers said.
But the resurgence of mountain pine beetles, which is decimating forests in Canada and in the western U.S., is due to an absence of bitterly cold winter nights, which used to kill the beetles. Instead, enough of them live through the year, enabling them to “ravage tens of millions of acres of forests, damage so severe it can be seen from space,” as The New York Times put it.
The well-documented drop in Arctic summer sea ice is also cited in the report, having occurred much faster than anticipated. A complete disappearance of Arctic summer ice, which could happen within the next several decades, could have marked impacts on communities and animals near the Arctic itself, as well as undetermined effects on weather patterns worldwide.
Much of this is already known to Indigenous Peoples, whose communities are at the forefront of climate change’s effect on daily life and the environment. Many have already made plans to adapt.
The trick, according to the report, lies in averting the thresholds so as to stay on the preservation side of the tipping point, the researchers said, adding that more research is needed.
"Right now we don't know what many of these thresholds are," White said. "But with better information, we will be able to anticipate some major changes before they occur and help reduce the potential consequences."