NASA: 2017 was second hottest year on record -- trailing only 2016
Posted January 18, 2018 7:01 p.m. EST
SAN FRANCISCO -- The planet continued its dramatic warming in 2017, federal scientists reported Thursday, logging one of its hottest years on record even as the warming influence of a recent El Nino ceased.
The extraordinary heat dovetailed with a year of climate extremes in which residents in places like California didn't need data sets to observe the floods and fire that are expected to become only more common as the earth gets hotter.
``We can just look back to the last year'' to see the dangers of climate change, said Rachel Licker, senior climate scientist at the Union of Concerned Scientists, which advocates for actions to counter global warming. ``These kinds of events could increase in frequency and that's certainly cause for alarm in the West.''
NASA reported Thursday that 2017 was the second warmest year in 138 years of record-keeping, following only 2016. The National Oceanic and Atmospheric Administration reported that 2017 was the third warmest year, trailing 2015 and 2016. The discrepancy resulted from using different data sources.
In any case, scientists at both agencies marveled over the heat that endured last year in the absence of an El Nino weather pattern and amid an emerging and opposite La Nina cooling pattern. If such short-term influences are factored out, 2017 was the hottest year on record, the scientists said.
``This really brings it home, the warmth that we're seeing,'' said Gavin Schmidt, director of NASA's Goddard Institute for Space Studies.
The nearly 2-degree temperature rise recorded by federal scientists since the 1800s is both severe and daunting. The trend is said to be driving sea level rise, melting ice caps, prompting mass extinctions and contributing to increasingly extreme weather.
Last year's flooding in Northern California and the deadly firestorm in Wine Country were among several weather-related events that made 2017 the nation's costliest for disaster response since reliable record-keeping begin in 1980.
Thursday's joint report by NASA and NOAA, which attributes global warming to human-generated greenhouse gases, is the most significant update on climate change since President Trump mocked the phenomenon in a December tweet. Trump has in the past referred to climate change as a hoax.
``In the East, it could be the COLDEST New Year's Eve on record. Perhaps we could use a little bit of that good old Global Warming that our Country, but not other countries, was going to pay TRILLIONS OF DOLLARS to protect against,'' Trump wrote. ``Bundle up!''
The administration's policies have fiercely diverged from its science. Trump has vowed to abandon the international deal struck in Paris to reduce greenhouse gases and has promised to repeal Obama's Clean Power Plan to control emissions.
Federal scientists said Thursday it's not their job to develop the nation's climate strategy. But they made the expectation that curbing the release of greenhouse gases would slow the alarming trend.
``All of the warming in the last 60 years is attributable to human activities,'' said Schmidt. ``Carbon dioxide emissions are the No. 1 component of that.''
With the United States taking little initiative on climate change amid scientific consensus that consequences will worsen if temperatures rise more than 3.6 degrees Fahrenheit above pre-industrial times, the effort to reduce heat-trapping emissions has fallen upon states like California.
California has adopted an ambitious goal of reducing its greenhouse gases 40 percent below 1990 levels by 2030. The state has introduced regulations designed to hit that target, including a cap-and-trade program that seeks to limit harmful emissions by requiring businesses to buy permits to pollute.
Several states and local governments have joined California in pledging to support the Paris climate deal as part of the Under2 Coalition.
``California has asserted itself as a leader both domestically and internationally, and hopefully it will inspire others,'' Licker said.
But without commitment from the White House, Licker and others said, keeping temperatures below the targeted 3.6-degree mark will be nearly impossible.
``Obviously nothing replaces the catalyst that comes from federal leadership,'' Licker said.
In Thursday's report, NASA said 2017's temperature averaged 1.62 degrees above the 1951-to-1980 mean. NOAA reported last year's temperature was 1.51 degrees above the 20th century average.
The measurements come from thousands of weather stations on land and sea. The NASA calculation differs from NOAA's in that it includes a stronger influence from the Arctic, which is warming at a faster pace than most other spots.
According to both data sets, the past four years were the four hottest on record. Seventeen of the 18 warmest years have occurred since 2001.
The slight cooling in 2017 comes with the ebbing El Nino, essentially a warming of Pacific equatorial waters and a change-up in tropical trade winds that tends to increase global temperatures.
At the same time, a La Nina began to emerge in 2017, a phenomenon marked by cooler ocean temperatures in the tropics and generally lower worldwide temperatures.
Also Thursday, the National Weather Service's Climate Prediction Center released its seasonal forecast, suggesting that the same La Nina is likely to reduce precipitation in the southern tier of the U.S. over the next three months, including Southern California.
The forecast bodes poorly for California's snowfall, which is critical to the state's water supply, though a dry year would be partly offset by the ample supplies that came with last winter's near-record storms.
With the La Nina expect to fade by spring, federal scientists said, the planet will probably see another hot year.
``It will almost certainly be a top-five year and possibly a top-two year,'' Schmidt said of 2018. ``The long-term trends are clear.''