In a week full of climate-related terrors, don’t expect to find much good news in the American Meteorological Society’s annual report card on the state of the planet.
For the past 28 years, the National Oceanic and Atmospheric Administration’s National Centers for Environmental Information (NCEI) has published a “State of the Climate” report, an exhaustive accounting of the planet’s vital signs and weather-related trends for every region worldwide. But this year’s installment of the 310-page report, published in the Bulletin of the American Meteorological Society with contributions from 524 scientists in 65 countries, feels a little different, according to NOAA’s Derek Arndt, one of the report’s three lead editors.
“When I started as the lead of this report, we were documenting global temperature and ocean heat content and all of the numbers like you would get in an annual physical,” said Arndt, who’s worked on the last nine years worth of reports. “Now we’re documenting things like loss of coral reef, coastal erosion, and inland flooding—things that are actually tangible and visible and affect the quality of our collective lives.”
What’s changed in a decade, he added, is that what were once worrisome warning signs have blossomed into full-blown manifestations of a warming world. “The symptoms—the direct interruptions of our lives—are just much more observable than they were 10 years ago,” he said.
That conclusion should not exactly come as a shock—not when the biggest wildfire in the history of California fails to rank as “the week’s worst climate news.” (That would be the “Hothouse Earth” scenario you may have been hearing about.) But the portrait of the planet that the BAMS report draws as the Anthropocene epoch picks up speed is still plenty disturbing: The year saw record-high sea levels and upper ocean temperatures and new lows in sea ice at the top and bottom of the world. Coral reefs had “unprecedented” damage from June 2014 to May 2017, leaving more than 95 percent of coral dead in some reef areas. Greenhouse gas concentrations reached record levels in 2017: The average global level of carbon dioxide last year was the highest ever measured in the modern global record (the past 38 years) and in other records going back as long as 800,000 years.
Depending on the dataset used, 2017 was either the second- or third-warmest year in history, but the hottest non-El Niño year on record. Land and sea surface temperatures surpassed the 1981–2010 average throughout much of the globe.
Overall, the report shows global temperatures ticking up 0.68–0.86 degrees Fahrenheit above the 1981–2010 average, part of a longer warming trend that has seen temperatures rise since 1975 at a rate of 2.7–3.2 degrees Fahrenheit per century. From 1901 to 1975, the planet’s surface warmed at a rate of 1.3–1.6 degrees Fahrenheit per century—meaning the rate of global temperature rise has almost doubled since 1975.
For the planet’s urban dwellers, the most alarming findings involve both rising global temperatures and sea levels, as well as the increase in inland flooding.
“The overall trend of a few degrees over a century may not seem like much,” said Arndt. “But the reality is that doesn’t happen evenly over every day or every place in the world. The ways it affects us, and particularly those of us who live in cities, are the extreme events get more extreme. They last longer, they are more intense, they are more frequent.” Indeed, this summer’s heat has claimed lives in cities unaccustomed to high temperatures in Canada, Northern Europe and Asia: “Just the last few weeks are a good example of the kind of heat waves that are becoming more common in a warming world.”
An urbanizing world is also one that’s increasingly vulnerable to rising seas: Eight of the ten largest cities in the world, including Tokyo, Mumbai, New York City, and Shanghai, are coastal, and an estimated 10 percent of the global population (and 40 percent of Americans) live in coastal areas. According to the report, global average sea levels in 2017 were the highest since satellite recording started in 1993. Global sea levels have been rising every year for the past six and in 22 of the last 24 years.
In 2017, the report tallied 16 “billion-dollar disasters” in the U.S.—weather and climate-related events like storms and floods that resulted in losses of over $1 billion. That added up to about $300 billion total in direct losses, the costliest year for total losses from billion-dollar disasters since tracking began in 1980. Among the extraordinary extreme weather events from 2017, the report singles out Hurricane Harvey—“the wettest known tropical cyclone to impact the United States”—for its “historic inland rainfall and flooding.” Harvey also came with a near-record price tag, with damages estimated by NOAA at $125 billion, second only to Katrina in 2005.
It’s notable that the financial toll of climate-related disasters have become part of the BAMS report’s annual accounting—a sign that monitoring a warming world means tracking direct economic costs, not just weather observations. “We’ve moved from an era in which the numbers are alarming into an era in which the symptoms are consequential,” Arndt said. “And unfortunately not unexpected.”