Arctic sea ice may be thinning twice as fast as previously thought, a team of climate scientists thinks.
Sea ice thickness is a sensitive indicator of Arctic climate change and is declining over the long term, despite significant year-on-year variability.
Using data collected from two climate monitoring satellites (Envisat and CryoSat-2), University College London (UCL) researchers hypothesized that a diminishing amount of ice below the waterline is hidden by the weight of overlying snow, which could suggest that sea ice thickness may decrease faster in some regions than previously calculated.
Sea ice cover moderates the exchange of moisture, heat and momentum between the atmosphere and the polar oceans, affecting regional ecosystems, hemispheric weather patterns and global climate. Thicker sea ice is more thermally insulating and limits heat transfer from the ocean to the atmosphere in winter.
Therefore, there is a risk that thinning sea ice will cause global temperatures to rise even further than the increases already caused by human-induced climate change.
While continuous and consistent monitoring of pan-Arctic sea ice thickness was not possible until recently, a combination of several techniques has suggested a significant decrease in thickness since the 1950s.
Satellite altimeters using both radar and lidar have provided a valuable record of changing sea ice thicknesses. ice thickness, but are often limited for various reasons.
The UCL team also said the thinning of sea ice in the Arctic coastal seas could disrupt human activity in the region, such as shipping along the Northern Sea Route, as well as the extraction of resources from the seabed, such as oil, gas and minerals.
“More ships navigating the route around Siberia would reduce the fuel and carbon emissions needed to transport goods around the world, particularly between China and Europe,” said UCL’s Robbie Mallett, the study’s lead author.
“However, it also increases the risk of fuel wastage in the Arctic, the consequences of which can be serious. “The thinning of coastal sea ice is also a concern for indigenous communities as it increasingly exposes coastal settlements to strong weather and swells from the emerging ocean.
” The researchers believe the sea ice decline in the Arctic’s coastal regions was 70 to 100 percent faster than previously thought.
Study co-author Professor Julienne Stroeve, of UCL Earth Sciences, said: “There are some uncertainties in measuring sea ice thickness, but we believe our new calculations are a big step forward in terms of a more accurate interpretation of the data we have from satellites.
“We hope this work can be used to better assess the performance of climate models that predict the long-term effects of climate change in the Arctic – a region that is warming three times faster than the world and of which millions of square kilometers of ice are essential to keep the planet cool.”