Extreme events in streams and rivers in arctic and subarctic regions in an uncertain future

• Published in: Freshwater Biology
• Main Authors: Nilsson, Christer, Polvi, Lina E., Lind, Lovisa
• Other Authors: Svenska Forskningsrådet Formas
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2015
• Subjects: Climate change; Ice; permafrost; Subarctic; taiga; Tundra
• Online Access: http://dx.doi.org/10.1111/fwb.12477; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Ffwb.12477; https://onlinelibrary.wiley.com/doi/pdf/10.1111/fwb.12477

Summary We review the predicted changes in extreme events following climate change in flowing waters in arctic and subarctic regions. These regions are characterised by tundra or taiga ecosystems in either erosional or depositional glacial landforms or presently glacierised areas of the N orthern H emisphere. The ecological and geomorphic effects of extreme meteorological and hydrological events, such as episodes of strongly increased precipitation, temperatures and flows, can be exacerbated by altered base conditions. For example, winter temperature variations between frost and thaw will become more frequent at many places because mean temperature during the winter is closer to 0 °C, potentially leading to changes in the production of ice and intensified disturbance of riparian and aquatic habitats during extreme floods. Additionally, thawing of permafrost and glaciers can lead to increased bank erosion because of thaw slump and glacial outburst floods. We discuss the abiotic and biotic effects of these and other extreme events, including heavy precipitation, floods, drought and extreme air or water temperatures, and summarise our findings in a model that aims to stimulate further research in this field.