2019 was second-hottest year on record, closing out hottest decade
The past 10 years were the warmest decade on record, closed out by the second-hottest year on record in 2019, according to an annual global climate report released today by NASA and the National Oceanic and Atmospheric Administration, or NOAA. The past five years have been the warmest of the last 140 years.
"Every decade since the 1960s clearly has been warmer than the one before," said Gavin Schmidt, director of NASA's Goddard Institute for Space Studies.
"If you think you've heard this story before, you haven't seen anything yet," Schmidt told The Associated Press. "This is real. This is happening."
The report draws on data from more than 20,000 weather stations, ship and buoy-based observations of sea surface temperatures, as well as temperature measurements from Antarctic research stations. Record high temperatures were recorded across parts of all oceans, and no land or ocean areas were record cold for the year.
The independent analyses from NASA and NOAA show that the average global surface temperature has risen every decade since 1880, and the rate of increase more than doubled after 1981.
The average global surface temperature is now more than 2 degrees Fahrenheit above pre-industrial levels.
"We crossed over into more than 2 degrees Fahrenheit warming territory in 2015 and we are unlikely to go back," Schmidt said. "This shows that what's happening is persistent, not a fluke due to some weather phenomenon: we know that the long-term trends are being driven by the increasing levels of greenhouse gases in the atmosphere."
Under the terms of the 2015 Paris Agreement, countries committed to "holding the increase in the global average temperature to well below 2°C [Celsius] above pre-industrial levels, and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels." In 2017, President Trump announced the U.S. would withdraw from the landmark climate agreement, though the withdrawal won't be final until the day after the 2020 election.
The past decade averaged 1.4 degrees Fahrenheit higher than the 20th century average, according to the report. This average is one-third of a degree (Fahrenheit) warmer compared to the average from 2000-2010 — which had been the hottest decade on record.
While global warming has increased over the past decade, so has global comprehension of its impact, according to Dr. Noah Diffenbaugh, senior fellow at the Stanford Woods Institute for the Environment and a professor of earth science at Stanford University.
"It's a decade when our understanding of climate change has grown in many ways... we have seen big steps forward in understanding how the global warming that's already happened is impacting people," Diffenbaugh said.
"We now have clear evidence that people and ecosystems are being impacted," he said. "In many cases, we're seeing a pervasive human fingerprint on extreme (weather) events."
NOAA reported earlier this month that extreme weather and climate-related disasters cost the U.S. $45 billion in damage in 2019.
Dr. Renee Salas, a professor of emergency medicine at Harvard Medical School and a Yerby Fellow at the Center for Climate, Health, and the Global Environment at the Harvard T.H. Chan School of Public Health, studies how heat, and especially extreme heat, affects communities and public health. Salas said that if the earth was a patient, global warming can be looked at much like how a doctor sees a fever — a symptom that indicates an underlying problem.
"The planet has a fever, and that's a symptom," Salas said. "We already know what the cause is, and that's greenhouse gas emissions and fossil fuel combustion. The diagnosis is political will."
