Climate change is “unequivocal” and rapidly intensifying, and some of the changes already in motion—such as continued sea level rise—are irreversible over hundreds to thousands of years, finds the latest report from the Intergovernmental Panel on Climate Change (IPCC), released Aug. 9. The IPCC Working Group I report, “Climate Change 2021: the Physical Science Basis,” was approved by 195 member governments of the IPCC, having been prepared by 234 scientists from 66 countries. The report concludes that human influence has warmed the planet at a rate that is unprecedented in at least the last 2,000 years. Human-induced climate change is already affecting many weather and climate extremes in every region across the globe—including heatwaves, droughts, and tropical cyclones.
In 2019, atmospheric concentrations of carbon dioxide (CO2) were higher than at any time in at least two million years, and concentrations of methane and nitrous oxide higher than at any time in the last 800,000 years. Global surface temperature has increased faster since 1970 than in any other 50-year period over a least the last 2,000 years. Temperatures during the most recent decade (2011–2020) exceed those of the most recent multi-century warm period, around 6,500 years ago, the report states.
The global mean sea level has risen faster since 1900 than over any preceding century in at least the last 3,000 years.
The report emphasized that there is still time to act. Wth strong and sustained cuts in emissions of CO2 and other greenhouse gases, global temperatures could stabilize within 20 to 30 years.
“It has been clear for decades that the Earth’s climate is changing, and the role of human influence on the climate system is undisputed,” said IPCC Working Group I co-chair ValĂ©rie Masson-Delmotte of France. “Yet the new report also reflects major advances in the science of attribution—understanding the role of climate change in intensifying specific weather and climate events.”
The United States joined the other 194 IPCC member governments in approving the Working Group I report. “The Intergovernmental Panel on Climate Change’s (IPCC) newest report makes it clear–climate change is already a crisis,” said US Secretary of State Antony Blinken. “Most importantly, the report finds we are already edging closer to a 1.5 degrees Celsius warmer world, and every day emissions rise the prospects for averting the worst impacts of climate change become dimmer. This is why it is essential that all countries—in particular the major economies—do their part during this critical decade of the 2020s to put the world on a trajectory to keep a 1.5 degrees Celsius limit on warming within reach.”
“This is why the United States has committed to a 50-52 percent reduction in emissions from 2005 levels in 2030 and is marshaling the entire federal government to tackle the climate crisis,” Blinken added.
UN Secretary-General AntĂłnio Guterres said the Working Group’s report is nothing less than “a code red for humanity.”
“We are at imminent risk of hitting 1.5 degrees in the near term,” Guterres said. “The only way to prevent exceeding this threshold is by urgently stepping up our efforts, and pursuing the most ambitious path. We must act decisively now, to keep 1.5 alive.”
Condensed from Environment News Service, Aug. 9
Note: The 2015Â Paris Agreement sets a 2 C rise within the current century as a maximum, but urges countries to work toward a 1.5 C rise. Recent studies have found that the 1.5 C rise will be reached within five years.
Photo: CalFire
Ice Age fears… again
A new study by the Potsdam Institute for Climate Impact Research, published in Nature and Climate Change, warns of destabilization of the Atlantic Meridional Overturning Circulation (AMOC) due to decline in Arctic sea ice, again raising fears of a new Ice Age. (MSN, CNN)
Rain falls on peak of Greenland ice cap: not good
For the first time on record, precipitation on Aug. 14 at the summit of Greenland’s inland ice cap—some two miles above sea level and more than 500 miles north of the Arctic Circle—fell as rain, not snow.Â
Arctic heating four times faster than whole planet
The Arctic is heating up nearly four times faster than the Earth as a whole, according to new research. Scientists previously estimated the Arctic is heating about twice as fast as the globe overall. The new study finds that over the last 43 years, the region has warmed 3.8 times faster than the planet as a whole.
“The Arctic is more sensitive to global warming than previously thought,” said Mika Rantanen of the Finnish Meteorological Institute, who is one of the authors of the study published in the journal Communications Earth & Environment. (NPR)
10 inches of sea level rise locked in: study
Widespread ice losses from Greenland have locked in nearly a foot of global sea level rise, with new research suggesting there is no way to stop it even if the world ceased release of greenhouse emissions today. The study, published in the journal Nature Climate Change, finds that the overall ice loss from Greenland’s ice sheet will trigger at least 10 inches of sea level rise, no matter the scenario for further global warming. Sea level has already risen 8–9 inches (21–24 centimeters) since 1880. (NYT, CNN, New Atlas)
Greenland melt could double sea level rise projections
A glacier in north Greenland is melting faster and in a different way than scientists previously thought, with troubling implications for the future speed of global sea-level rise. The new discovery was published in the Proceedings of the National Academy of Sciences on May 8. The scientists found that warming ocean water had melted a cavity in the bottom of Petermann Glacier, which is taller than the Washington Monument, as the Associated Press reported. If other glaciers in Greenland and Antarctica behave the same way, it could double predictions for how quickly carbon emissions melt ice and raise sea levels. (Alaska Native News)
Gulf Stream could collapse as early as 2025: study
The Gulf Stream system could collapse as soon as 2025, a new study suggests. The shutting down of the vital ocean currents, called the Atlantic Meridional Overturning Circulation (AMOC) by scientists, would bring catastrophic climate impacts.
A collapse of the AMOCÂ would have disastrous consequences around the world, severely disrupting the rains that billions of people depend on for food in India, South America and west Africa. It would increase storms and drop temperatures in Europe, and lead to a rising sea level on the eastern coast of North America. It would also further endanger the Amazon rainforest and Antarctic ice sheets.
“I think we should be very worried,” said Prof Peter Ditlevsen, at the University of Copenhagen in Denmark, and who led the new study. “This would be a very, very large change. The AMOC has not been shut off for 12,000 years.” (The Guardian)
Antarctic sea ice levels dive in ‘five-sigma event’
This winter has confirmed what scientists had feared—the sea ice around Antarctica is in sharp decline, with experts now concerned it may not recover. Earlier this year, scientists observed an all-time low in the amount of sea ice around the icy continent, following all-time lows in 2016, 2017 and 2022.
Usually, the ice has been able to recover in winter, when Antarctica is reliably dark and cold. But this year is different. For the first time, the sea ice extent has been unable to substantially recover this winter, leaving scientists baffled.
Physical oceanographer Edward Doddridge has been communicating with scientists and the community about the drastic changes happening around Antarctica. He said vast regions of the Antarctic coastline were ice free for the first time in the observational record.
“To say unprecedented isn’t strong enough,” Dr Doddridge said. “For those of you who are interested in statistics, this is a five-sigma event. So it’s five standard deviations beyond the mean. Which means that if nothing had changed, we’d expect to see a winter like this about once every 7.5 million years. It’s gobsmacking.” (Radio Australia)
Greenland ice sheet melting causing alarm among scientists
The steady deterioration of the Greenland Ice Sheet, with almost 3,800 billion metric tons of ice melting away from 1992 to 2018, invites grave global concern. The rate of loss as risen exponentially since the 1990s. The Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) team, which has been closely monitoring this situation, attributes the primary cause of this mass reduction to the increase in meltwater runoff, accounting for nearly 1,970 billion tons of the total ice loss. The rapidly diminishing ice sheet, a pivotal factor in the ongoing rise of global sea levels, offers a potential threat of drastic changes in sea levels and global climate patterns if the current warming trend continues. Meltwater runoff has risen by 21%, resulting in 3.5 trillion tons of ice loss from Greenland, raising global sea levels by one centimeter. This could also destabilize ocean current patterns that bring warm water north and cold water south (AMOC), facing Europe with the prospect of colder and longer winters. (BNN, PRI)