Arctic warming cascades through ocean and over land
Greenhouse gas emissions reached a new high last year, putting the world on track for an average temperature rise of 3 degrees Celsius, a U.N. report showed on Wednesday.
The report by the United Nations Environment Programme (UNEP) – the latest to suggest the world is hurtling toward extreme climate change – follows a year of sobering weather extremes, including rapid ice loss in the Arctic as well as record heat waves and wildfires in Siberia and the U.S. West.
On Monday, researchers at Europe’s Copernicus Climate Change Service said last month was the hottest-ever November on record. Meanwhile, The Arctic region has had its second-warmest year since 1900, continuing a pattern of extreme heat, ice melt and environmental transformation at the top of the world, scientists reported Tuesday.
“The year 2020 is on course to be one of the warmest on record, while wildfires, storms and droughts continue to wreak havoc,” said Inger Andersen, UNEP’s Executive Director.
The annual “emissions gap” report measures the gap between anticipated emissions and those consistent with limiting the global temperature rise this century as agreed in the 2015 Paris Agreement.
Under the global climate pact, nations have committed to a long-term goal of limiting the average temperature rise to below 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit it even further to 1.5 C.
Emissions have, however, grown by an average 1.4 percent per year since 2010, with a steeper increase of 2.6 percent last year due, partly due to a large increase in forest fires.
Total 2019 emissions of carbon dioxide equivalent (GtCO2e) hit a new record of 59.1 gigatonnes. This year, there has been a temporary emissions dip as economies slowed due to the coronavirus pandemic.
The resulting drop in travel, industrial activity and electricity generation are likely to work out at a 7% reduction in emissions, the report said. That translates to only a 0.01C reduction in global warming by 2050.
Green investment under government stimulus packages to pull economies out of the pandemic-induced slump could cut up to 25% off emissions predicted in 2030.
Such packages could put emissions in 2030 at 44 GtCO2e – within the range that gives a 66% chance of holding temperature rises to below 2C, but still insufficient to achieve the 1.5C goal.
Whereas, in the 15th annual Arctic Report Card, released by the U.S. National Oceanic and Atmospheric Administration (NOAA), researchers detail the stark ways in which climate change is altering the long-frozen region.
“Taken as a whole, the story is unambiguous,” Alaska-based climate scientist Rick Thoman, one of the report’s editors, said in a statement. “The transformation of the Arctic to a warmer, less frozen and biologically changed region is well underway.”
Among the milestones hit this year was the second-lowest minimum sea ice extent in the satellite record, at 3.74 million square kilometers reached on Sept. 15. That was beaten only by the low in 2012, when a late-season cyclonic storm broke up much of that year’s remaining ice.
The minimum sea ice extent has never risen above its level in 2007 since then.
The warmer waters were also connected to warmer air over Arctic lands, triggering glacial melt along the fringes of the Arctic Ocean. A record-hot summer in Siberia, linked to climate change, led to massive wildfires in the area as well as delaying the refreezing of the Arctic Ocean.
It also led to the lowest June snow cover in Eurasia since records began in 1967, the report said. Overall, the annual snow cover on land has been decreasing since 1981 at a rate of 3.7 percent per decade – with an even steeper decrease of 15 percent per decade for the May-June period, the report said.
From year to year, the warming trend has shifted to focus on different areas around the Arctic. This year’s warmth centered around Siberia. In 2019, the hotspots were around the Bering and Chukchi seas off Alaska, with soaring water temperatures and widespread bird and mammal die-offs recorded.
Water entering the ocean from melting glaciers and the ice sheet covering Greenland is raising global sea levels. In 2019, the most recent year for which glacier data is available – and a record-hot year in Alaska – the state’s glaciers lost more mass than in any other year on record, the report card said.
The United Nations and Britain are holding an online event on Saturday to mark the fifth anniversary of the Paris Agreement, and governments are under pressure to come forward with tougher climate targets before the end of the year.
A growing number of countries have committed to net zero emissions by mid-century but these need to be translated into strong near-term policies and action, the UNEP report said.
“The levels of ambition in the Paris Agreement still must be roughly tripled for the 2C pathway and increased at least fivefold for the 1.5C pathway,” it added. (Reuters)