A recent study from the Potsdam Institute for Climate Impact Research warns that global temperature rise might exceed previous predictions due to carbon cycle feedback loops, stressing the need for accelerated carbon reduction efforts.
Global warming over the next millennium could surpass previous estimates because of carbon cycle feedback loops, according to a groundbreaking study by the Potsdam Institute for Climate Impact Research (PIK). This research underscores the critical need for rapid and effective carbon reduction strategies to meet the Paris Agreement’s target of keeping global temperature rise well below 2 degrees Celsius.
The study, led by PIK scientist Christine Kaufhold, is the first to make long-term projections over the next 1,000 years while integrating established carbon cycle feedbacks, including methane.
“Our study demonstrates that even in emission scenarios typically considered ‘safe’, where global warming is generally considered to remain below 2°C, climate and carbon cycle feedbacks, like the thawing of permafrost, could lead to temperature increases substantially above this threshold,” Kaufhold said in a news release.
The research reveals that, under low-to-moderate emission scenarios, peak warming could be significantly higher than previously anticipated. This complicates the already formidable challenge of meeting the Paris Agreement goals.
“This highlights the urgent need for even faster carbon reduction and removal efforts,” Kaufhold added.
Unlike many studies, which typically forecast outcomes only up to 2100 or 2300, this research ran simulations for an entire millennium using PIK’s newly developed Earth system model, CLIMBER-X.
CLIMBER-X integrates essential physical, biological and geochemical processes, including atmospheric and oceanic conditions, and represents an interactive carbon cycle incorporating methane.
The team explored future climate scenarios over the next thousand years under three low-to-moderate emission pathways. The study’s model uniquely accounts for major carbon cycle feedbacks, allowing the researchers to estimate potential additional warming from these feedback mechanisms.
The research also underscores the significance of Equilibrium Climate Sensitivity (ECS), which measures the global temperature increase associated with a doubling of CO₂ concentrations.
The Intergovernmental Panel on Climate Change defines ECS as “very likely” between 2 degrees Celsius and 5 degrees Celsius.
“Our results show that the Paris Agreement’s goal is only achievable under very low emission scenarios and if the ECS is lower than current best estimates of 3°C,” added co-author Matteo Willeit, a PIK scientist. “If the ECS exceeds 3°C, carbon reduction must accelerate even more quickly than previously thought to keep the Paris target within reach.”
The study highlights the pivotal role ECS plays in predicting future climate outcomes while stressing the importance of more precise ECS quantification. Failure to accurately estimate ECS could drastically alter our climate projections, revealing that small changes in emissions may lead to much larger temperature increases than expected.
“Our research makes it unmistakably clear: today’s actions will determine the future of life on this planet for centuries to come,” co-author Johan Rockström, a PIK director, concluded. “The window for limiting global warming to below 2°C is rapidly closing. We are already seeing signs that the Earth system is losing resilience, which may trigger feedbacks that increase climate sensitivity, accelerate warming and increase deviations from predicted trends. To secure a liveable future, we must urgently step up our efforts to reduce emissions. The Paris Agreement’s goal is not just a political target; it is a fundamental physical limit.”
This study, published in Environmental Research Letters, marks a significant advance in our understanding of long-term climate dynamics, urging swift and comprehensive action to mitigate impending climate risks.