Arctic sea ice thinning faster than expected: Researchers

Sea ice in the coastal regions of the Arctic may be thinning up to twice as fast as previously thought according to a new modelling study led by UCL researchersSea ice thickness is inferred by measuring the height of the ice above the water and this measurement is distorted by snow weighing the ice floe down Scientists adjust for this using a map of snow depth in the Arctic that is decades out of date and does not account for climate changeIn the new study published in the journal The Cryosphere researchers swapped this map for the results of a new computer model designed to estimate snow depth as it varies year to year and concluded that sea ice in key coastal regions was thinning at a rate that was 70 to 100 per cent faster than previously thoughtRobbie Mallett UCL Earth Sciences the PhD student who led the study said The thickness of sea ice is a sensitive indicator of the health of the Arctic It is important as thicker ice acts as an insulating blanket stopping the ocean from warming up the atmosphere in winter and protecting the ocean from the sunshine in summer Thinner ice is also less likely to survive during the Arctic summer meltPrevious calculations of sea ice thickness are based on a snow map last updated 20 years ago Because sea ice has begun forming later and later in the year the snow on top has less time to accumulate Our calculations account for this declining snow depth for the first time and suggest the sea ice is thinning faster than we thoughtAlso read Humaninduced climate change responsible for nearly a third of heat deaths StudyCoauthor Professor Julienne Stroeve UCL Earth Sciences said There are a number of uncertainties in measuring sea ice thickness but we believe our new calculations are a major step forward in terms of more accurately interpreting the data we have from satellitesWe hope this work can be used to better assess the performance of climate models that forecast the effects of longterm climate change in the Arctic a region that is warming at three times the global rate and whose millions of square kilometres of ice are essential for keeping the planet coolTo calculate sea ice thickness researchers used radar from the European Space Agencys CryoSat2 satellite By timing how long it takes for radar waves to bounce back from the ice they can calculate the height of the ice above the water from which they can infer the ices total thicknessIn the new study researchers used a novel snow model previously developed by researchers at UCL and Colorado State University SnowModelLG which calculates snow depth and density using inputs such as air temperature snowfall and ice motion data to track how much snow accumulates on sea ice as it moves around the Arctic OceanBy combining the results of the snow model with satellite radar observations they then estimated the overall rate of decline of sea ice thickness in the Arctic as well as the variability of sea ice thickness from year to yearThey found that the rate of decline in the three coastal seas of Laptev Kara and Chukchi seas increased by 70 98 and 110 per cent respectively when compared to earlier calculationsThey also found that across all seven coastal seas the variability in sea ice thickness from year to year increased by 58 per centSea ice in the coastal seas typically varies from half a metre to two metres thick Increasingly the ice in this region is not surviving the summer melt The faster thinning of sea ice in the coastal Arctic seas has implications for human activity in the region both in terms of shipping along the Northern Sea Route for a larger part of the year as well as the extraction of resources from the sea floor such as oil gas and mineralsMallett said More ships following the route around Siberia would reduce the fuel and carbon emissions necessary to move goods around the world particularly between China and EuropeHowever it also raises the risk of fuel spillages in the Arctic the consequences of which could be dire The thinning of coastal sea ice is also worrying for indigenous communities as it leaves settlements on the coast increasingly exposed to strong weather and wave action from the emerging oceanMallett Professor Stroeve and coauthor Michel Tsamados UCL Earth Sciences spent several weeks investigating snow and ice in the Arctic onboard the German research vessel Polarstern which explored the central Arctic Ocean in 2019 and 2020The study was funded by the UKs Natural Environment Research Council the European Space Agency ESA and the US National Aeronautics and Space Administration NASAThis story has been sourced from a third party syndicated feed agencies Midday accepts no responsibility or liability for its dependability trustworthiness reliability and data of the text Midday managementmiddaycom reserves the sole right to alter delete or remove without notice the content in its absolute discretion for any reason whatsoever