Some of the nation’s leading climate scientists Monday sounded an alarm about the urgency of addressing climate change over the next decade, as a key index used to measure humans’ impact on the warming planet ticked higher.
“Unfortunately,” said Ko Barrett, a senior climate advisor to the National Oceanic and Atmospheric Administration and a vice chair of the Intergovernmental Panel on Climate Change, “what we see is dire.”
Barrett was giving a keynote address to NOAA’s 50th Global Monitoring Annual Conference. The conference is hosted by NOAA’s Global Monitoring Laboratory, which is based in Boulder, though the conference is virtual this year.
As the name suggests, the conference brings together scientists with an expertise in climate monitoring — one presentation Monday, for instance, involved the possible use of instruments mounted in commercial airliners to measure atmospheric levels of carbon dioxide and other gases. The work of those scientists undergirds projections of how much the world will warm in coming decades as a result of human-caused greenhouse gas pollution.
Among the conference’s highlights is the unveiling of the latest entry in NOAA’s Annual Greenhouse Gas Index, which is a way to show how much extra heat humans’ greenhouse gas pollution traps, committing the planet to a hotter world. This year’s index rose to 1.49 — 49% higher than in 1990.
Put another way, the index shows that there is 49% more heat currently trapped by human-emitted greenhouse gases than there was in 1990, said Ariel Stein, the acting director of the Global Monitoring Laboratory. Last year, the index sat at 1.47 — 47% higher than in 1990.
(The index uses 1990 as the baseline because that is the baseline year for the Kyoto Protocol and also the year of the first IPCC Scientific Assessment of Climate Change.)
The increase in the index is in line with increases over the past four years.
Carbon dioxide emissions are the biggest contributor to the increase in the index — 80% of the increase since 1990 is due to carbon dioxide. Three gases — carbon dioxide, methane and nitrous oxide — account for 90% of the increased heat trapped in the atmosphere due to human activity since the mid-1700s, Stein said.
“The scientific conclusion that humans are responsible for their increase is irrefutable,” Stein said.
Methane emissions, which can come from oil and gas production and from livestock agriculture but also from thawing permafrost in the Arctic, are also rising quickly. Stein said the 17 parts per billion increase in observed atmospheric methane levels last year was the largest annual increase on record.
To Barrett, the NOAA climate adviser, these numbers paint a stark picture: The world is on course to miss its goals for limiting temperature increase.
But, she said, it’s also important to focus on the reasons for optimism. Electric cars are gaining in popularity. Cities, through greener building practices and electrified transportation, are beginning to seize their opportunities to reduce emissions. Governments are taking serious steps to battle climate change.
“The next decade is a critical time to address the climate crisis,” Barrett said. “We have a small window to shift to a carbon-neutral economy and hold climate impacts in check.”