A new study indicates that the Arctic will retain about 1.5°C of warming and excess precipitation even if atmospheric carbon dioxide returns to pre-industrial levels. Researchers used multiple climate models to predict these irreversible changes, driven largely by ocean heat absorption. This highlights the challenges of reversing regional climate impacts through carbon dioxide removal efforts.
Researchers from the Institute of Atmospheric Physics in Beijing, led by Xiao Dong, analyzed 11 independent climate models to assess the Arctic's response to various carbon dioxide scenarios. Their findings, published in Environmental Research Letters, reveal that the region would hold onto approximately 1.5°C of warming compared to pre-industrial times, regardless of aggressive carbon dioxide removal (CDR) measures. Additionally, daily precipitation would increase by about 0.1 millimeters, a change Michael Meredith from the British Antarctic Survey describes as newly highlighted in such studies.
Current atmospheric CO2 levels stand at 1.5 times pre-industrial amounts, with the Arctic already experiencing over 3°C of warming. A prior March study noted that average sea ice extent would remain 1 million square kilometers smaller even after removing excess CO2. The primary driver is the ocean, which has absorbed 90 percent of global warming's heat and will continue to warm the Arctic for centuries, even as the atmosphere cools. Feedback mechanisms, such as diminishing sea ice exposing more open water to heat the air, could exacerbate this.
The team examined three scenarios: an abstract one where CO2 quadruples over 140 years, declines for another 140, and stabilizes for 60; an immediate emissions slash; and continued high emissions followed by CDR from 2070. In all cases, by 2100, the Arctic remains 1.5°C warmer with added precipitation. An exception appears south of Greenland and Iceland, where temperatures and precipitation may decrease due to a slowing Atlantic Meridional Overturning Circulation (AMOC), potentially leading to colder European winters.
Ongoing effects include permafrost thawing and Greenland ice sheet melting, contributing to sea level rise, as noted by Mark Serreze of the US National Snow and Ice Data Center. "These findings highlight the irreversible nature of Arctic climate change even under aggressive CDR scenarios," the researchers stated. While skepticism surrounds CDR's feasibility due to high costs, the Arctic may eventually cool over millennia.