Statistical forecasting of current and future circum‐Arctic ground temperatures and active layer thickness

• Main Authors: Aalto, J. (J.), Karjalainen , O. (O.), Hjort, J. (J.), Luoto, M. (M.)
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2018
• Subjects: Arctic; climate change; ensemble modeling; ground thermal regime; permafrost; uncertainty; Active layer thickness; Climate change
• Online Access: http://urn.fi/urn:nbn:fi-fe201903209456

Abstract Mean annual ground temperature (MAGT) and active layer thickness (ALT) are key to understanding the evolution of the ground thermal state across the Arctic under climate change. Here a statistical modeling approach is presented to forecast current and future circum‐Arctic MAGT and ALT in relation to climatic and local environmental factors, at spatial scales unreachable with contemporary transient modeling. After deploying an ensemble of multiple statistical techniques, distance‐blocked cross validation between observations and predictions suggested excellent and reasonable transferability of the MAGT and ALT models, respectively. The MAGT forecasts indicated currently suitable conditions for permafrost to prevail over an area of 15.1 ± 2.8 × 106km2. This extent is likely to dramatically contract in the future, as the results showed consistent, but region‐specific, changes in ground thermal regime due to climate change. The forecasts provide new opportunities to assess future Arctic changes in ground thermal state and biogeochemical feedback.