Arctic warming could speed up global 2°C temperature rise by eight years
A new modeling study led by researchers at University College London (UCL) has revealed a concerning connection between rapid warming in the Arctic and the acceleration of global temperature increases.
According to the study, accelerated warming in the Arctic is set to speed up the global 2°C temperature rise by eight years compared to the scenario where the Arctic warms at the average global rate.
Temperature thresholds
The Arctic region is heating up nearly four times faster than the global average. The new study sheds light on the global ramifications of this phenomenon, particularly regarding the temperature thresholds established in the Paris Agreement.
These thresholds, set at 1.5°C and 2°C, are critical markers in the global effort to manage climate change.
Focus of the study
The researchers set out to investigate by creating alternative climate change projections. The hypothetical models excluded the rapid warming currently observed in the Arctic.
By comparing these projections with those based on current trends, the team could assess the impact of Arctic warming on global temperatures.
Rate of Arctic warming is a concern
The results showed that without the Arctic’s rapid warming, the 1.5°C and 2°C thresholds would be breached five and eight years later than the projected dates of 2031 and 2051, respectively.
An additional concern raised by the study is the concept of Arctic amplification, which refers to the disproportionately fast warming of the Arctic region. This not only accelerates global temperature rise but also introduces significant uncertainty into climate projections.
The researchers noted that the variability in model forecasts for the Arctic is considerably larger than for other regions of the planet, complicating efforts to predict and prepare for future climate scenarios.
Uncertainty in climate forecasts
“Our study highlights the global importance of rapid Arctic warming by quantifying its large impact on when we are likely to breach critical climate thresholds. Arctic warming also adds substantial uncertainty to climate forecasts,” said study lead author and PhD candidate Alistair Duffey.
“These findings underscore the need for more extensive monitoring of temperatures in the region, both in-situ and via satellites, and for a better understanding of the processes occurring there, which can be used to improve forecasts of global temperature rise.”
Direct contribution of Arctic warming
The researchers did not quantify the ways in which Arctic warming affects the rest of the world, such as through sea ice retreat. Instead, the goal was to estimate the direct contribution of Arctic warming to global temperature increases.
“While our study focuses on how Arctic warming affects global temperature change, the local impacts should not be overlooked. A 2C temperature rise globally would result in a 4C annual mean rise in the Arctic, and a 7C rise in winter, with profound consequences for local people and ecosystems,” said study co-author Professor Julienne Stroeve.
“In addition, rapid warming in the Arctic has global consequences that we do not account for in this study, including sea level rise and the thawing of permafrost which leads to more carbon being released into the air.”
Arctic warming through amplification
Arctic amplification, which is most intense during winter, arises from various factors including the retreat of sea ice. This retreat leads to more sunlight and heat being absorbed by water, rather than being reflected back into space.
Additionally, the less vertical mixing of air at the poles compared to the tropics traps warmer air near the Earth’s surface.
How the research was conducted
The study utilized 40 climate models from the UN’s 2021 climate change report. These models use a three-dimensional grid to simulate physical processes across the Earth’s surface.
The researchers modified these models to create a hypothetical scenario where rapid Arctic warming was absent. They adjusted the temperature change rate in areas north of 66° North to match the rest of the planet, examining how this alteration would affect temperature projections under various emissions scenarios.
Critical insights
In scenarios where emissions are significantly reduced and net zero is achieved shortly after 2050, the study found that Arctic amplification could lead to a seven-year difference in reaching the 1.5°C increase threshold.
Notably, temperature projections for the Arctic showed greater variability across models compared to other regions, contributing 15 percent to the uncertainty in global projections, despite the Arctic’s relatively small surface area.
The Paris Agreement
The study underscores the significance of the 1.5°C and 2°C limits set by international agreements, such as the Paris Agreement. These limits are defined as the average global temperatures over a 20-year period being 1.5°C or 2°C higher than pre-industrial levels.
The Paris Agreement aims to keep global temperature rise “well below 2°C above pre-industrial levels” and pursue efforts to limit the increase to 1.5°C.
Unfolding crisis
The Arctic region has warmed by approximately 2.7°C since pre-industrial times, with this warming accelerating in the 21st century. The study’s findings are critical in understanding and addressing global climate change.
Dr. Robbie Mallett noted that Arctic climate change is often overlooked by politicians because most of the region is outside national boundaries. “Our study shows how much the Arctic impacts global targets like the Paris Agreement, and hopefully draws attention to the crisis that’s already unfolding in the region.”
This research was supported by the Natural Environment Research Council (NERC), the European Space Agency (ESA), and the Canada 150 Research Chairs Program.
The study is published in the journal Earth System Dynamics.
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