SOURCE: Scientific American

DATE: December 10, 2019

SNIP: Extreme events all over the world were marked by the influence of climate change in 2018: wildfires in California, heat waves in Europe and Asia, and record-low sea ice in the Arctic.

That’s according to an annual special report released yesterday in the Bulletin of the American Meteorological Society. The report, now in its eighth year, includes a collection of studies analyzing major events to determine whether climate change played a role—a field of research known as attribution science.

Typically, each report includes a number of events in which climate change had a significant influence—and a few in which it didn’t. But as the years go on, a trend seems to be emerging. More and more studies are finding the fingerprints of global warming on disastrous events.

Since 2011, when the first special bulletin was published, it’s “steadily seen an increase in the percentage of papers that find an influence versus not,” NOAA climate scientist Stephanie Herring, lead editor of the special report, said at a press conference announcing the findings.

Averaged across the past eight years, about 73% of published studies have found a role for climate change in the events they examined, versus about 27% that didn’t. But it isn’t an even split over time. In the last few years, more papers have pointed to the influence of global warming—about 95% of them these days, Herring noted.

The special bulletin doesn’t include every attribution study conducted each year. Other studies are published in other journals, continually widening the body of literature over time.

But the bulletin’s annual collection does provide a window into how both the science and the climate are changing over time.

There are two reasons the report may be finding more links to climate change as time goes on, experts suggest. One reason is that the influence of global warming is simply growing stronger.

Two years ago, studies in the bulletin found—for the first time ever—that some events would not have been possible without the influence of climate change. The same was true for some studies in last year’s report. For instance, a 2017 marine heat wave off the coast of Australia was found to have been “virtually impossible” in a world without climate change.

Most attribution studies find that a given event was simply made more likely to occur, or perhaps more intense, by the influence of global warming. To some experts, discovering entirely novel events in today’s warming climate is a reminder that the Earth is moving into unprecedented territory.