2017 Among Three Hottest Years; Arctic Melting Fast
January 6, 2018
The 2017 global land and ocean temperature will likely be among the three hottest years on record, and is expected to be the warmest year without a warming El Niño weather pattern in the tropical Pacific Ocean, according to the World Meteorological Organization, which relies on observations from its 191 member states and territories.
The first 11 months of the year were the third warmest on record, behind 2016 and 2015, with much warmer than average conditions dominating much of the world's land and ocean surfaces, according to the U.S. National Oceanic and Atmospheric Administration, NOAA.
Arctic temperatures continue to increase at double the rate of the global temperature increase. In addition, sea ice coverage in both the Arctic and Antarctic remain at near record lows, satellite data shows.
NASA's Goddard Institute for Space Studies, GISS, and the European Centre for Medium Range Weather Forecasts, ECMWF, Copernicus Climate Change Service both said that the past meteorological year, from December 2016 to November 2017, is the second warmest on record.
Now, the World Meteorological Organization will combine datasets from NOAA, NASA GISS, and the Met Office Hadley Centre and Climatic Research Unit (UK) for a consolidated temperature ranking for 2017.
"What is more important than the ranking of an individual year is the overall, long-term trend of warming since the late 1970s, and especially this century," said WMO senior scientist Omar Baddour. "Along with rising temperatures, we are seeing more extreme weather with huge socio-economic impacts," he said.
NOAA said the month of November was the fifth warmest on record, whilst NASA and ECMWF Copernicus Climate Change Service both said it was the third warmest.
Cooling La Niña conditions prevailed across the tropical Pacific Ocean during November 2017. WMO's latest Update indicates that weak La Niña conditions are expected to persist through the Northern Hemisphere winter.
During November 2017, warmer-than-average temperatures dominated across much of the world's land and ocean surfaces, with the most notable temperature departures from average across the Northern Hemisphere.
Parts of the western contiguous United States, northern Canada, northern and western Alaska, western Asia and Far Eastern Russia had temperature departures from average that were +2.0°C (+3.6°F) or greater, according to NOAA.
Arctic Temperatures Rising Fast
A NOAA-sponsored report shows that the warming trend transforming the Arctic persisted in 2017, resulting in the second warmest air temperatures, above average ocean temperatures, loss of sea ice, and a range of human, ocean and ecosystem effects.
Now in its 12th year, the Arctic Report Card is a peer-reviewed report that brings together the work of 85 scientists from 12 nations.
"While 2017 saw fewer records shattered than in 2016, the Arctic shows no sign of returning to the reliably frozen region it was decades ago," says the Arctic Report Card.
As an indication of swift regional climate change in and near the Arctic, the average temperature observed at the weather station at Utqiagvik, Alaska has now changed so rapidly that it triggered an algorithm designed to detect artificial changes in a station's instrumentation or environment.
Utqiagvik (say OOT-ki-aag'-vik) sits near Point Barrow, the northernmost point in America, on the Arctic Coast of northern Alaska. Now recognized by its Iñupiat place name, it is still commonly known as "Barrow."
Elsewhere in the Arctic, a separate analysis from the European ECMWF Copernicus Climate Change service found November's temperature was more than 6°Celsius above average in parts of Svalbard, Norway as it was in October.
One chapter in the Arctic Report Card shows, using historical data, that the current observed rate of sea ice decline and warming temperatures are higher than at any other time in the last 1,500 years, and likely longer than that.
The Arctic Report Card provides an annual update on how the region is faring environmentally, and compares these observations to the long-term record. This information can be used to inform decisions on adaptation by local, tribal, state and federal leaders as they confront both the obstacles and the possibilities posed by a changing climate to economic growth, national security, public safety and natural resource conservation.
"The rapid and dramatic changes we continue to see in the Arctic present major challenges and opportunities," said retired Navy Rear Adm. Timothy Gallaudet, Ph.D., acting NOAA administrator, who led the press conference to release the report card.
"This year's Arctic Report Card is a powerful argument for why we need long-term sustained Arctic observations to support the decisions that we will need to make to improve the economic well-being for Arctic communities, national security, environmental health and food security," said Gallaudet.
Major findings in this year's Arctic Report Card include:
Warmer air temperature. Average annual air temperature over land was the second highest after 2016 in the observational record, with a temperature 2.9 degrees Fahrenheit (1.6 Celsius) above the average for 1981 to 2010.
Declining sea ice. This year's maximum winter sea ice area, measured each March, was the lowest ever observed, while this year's minimum area, measured each September, was eighth-lowest on record. Sea ice is also getting thinner each year, with year-old ice comprising 79 percent of coverage, and multi-year ice just 21 percent. In 1985, multi-year ice accounted for 45 percent of sea ice.
Above average ocean temperature. Sea surface temperatures in August 2017 were 7.2 degrees Fahrenheit (4 Celsius) above the average in the Barents and Chukchi seas. Surface waters of the Chukchi Sea have warmed 1.26 degrees Fahrenheit (0.7 Celsius) per decade since 1982.
Arctic Ocean plankton blooms increasing. Springtime melting and retreating sea ice which allows sunlight to reach the upper layers of the ocean, continues to stimulate increased chlorophyll as measured by satellite, which indicates more marine plant growth across the Arctic. This increase has occurred since measurements began in 2003.
Greener tundra. Overall vegetation, including plants getting bigger and leafier, and shrubs and trees taking over grassland or tundra, increased across the Arctic in 2015 and 2016, as measured by satellite. The greatest increases over the last three decades are occurring on the North Slope of Alaska, Canada's tundra and Taimyr Peninsula of Siberia. The annual report on vegetation is based largely on data from sensors aboard NOAA weather satellites.
Snow cover up in Asia, down in North America. For the 11th year in the past 12, snow cover in the North American Arctic was below average, with communities experiencing earlier snow melt. The Eurasian part of the Arctic saw above average snow cover extent in 2017, the first time that's happened since 2005.
Less melt on Greenland Ice Sheet. Melting began early on the Greenland Ice Sheet in 2017, but slowed during a cooler summer, resulting in below-average melting when compared to the previous nine years. Overall, the Greenland Ice Sheet, a major contributor to sea level rise, continued to lose mass this past year, as it has since 2002 when measurements began.
This year's report card also includes special reports on how the warming trend is affecting valuable fisheries in the eastern Bering Sea; compromising roads, homes and infrastructure due to permafrost thaw; and threatening the high latitudes with increasingly frequent wildfires.
A separate report, published in the Bulletin of the American Meteorological Society, BAMS, said that last year's record global average temperatures, extreme heat over Asia, and unusually warm waters in the Bering Sea would not have been possible without human-caused climate change.
"This report marks a fundamental change," says Jeff Rosenfeld, editor-in-chief of BAMS. "For years scientists have known humans are changing the risk of some extremes. But finding multiple extreme events that weren't even possible without human influence makes clear that we're experiencing new weather, because we've made a new climate."