Key indicators of Arctic climate change: 1971–2017

• Published in: Environmental Research Letters
• Main Authors: Jason E Box, William T Colgan, Torben Røjle Christensen, Niels Martin Schmidt, Magnus Lund, Frans-Jan W Parmentier, Ross Brown, Uma S Bhatt, Eugénie S Euskirchen, Vladimir E Romanovsky, John E Walsh, James E Overland, Muyin Wang, Robert W Corell, Walter N Meier, Bert Wouters, Sebastian Mernild, Johanna Mård, Janet Pawlak, Morten Skovgård Olsen
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing 2019
• Subjects: Arctic climate change; observational records; AMAP; Environmental technology. Sanitary engineering; TD1-1066; Environmental sciences; GE1-350; Science; Q; Physics; QC1-999; Arctic; Climate change; Ice; permafrost; Sea ice; Tundra
• Online Access: https://doi.org/10.1088/1748-9326/aafc1b; https://doaj.org/article/9f8f294d2d3b40c9847fae7f7b4ef717

Key observational indicators of climate change in the Arctic, most spanning a 47 year period (1971–2017) demonstrate fundamental changes among nine key elements of the Arctic system. We find that, coherent with increasing air temperature, there is an intensification of the hydrological cycle, evident from increases in humidity, precipitation, river discharge, glacier equilibrium line altitude and land ice wastage. Downward trends continue in sea ice thickness (and extent) and spring snow cover extent and duration, while near-surface permafrost continues to warm. Several of the climate indicators exhibit a significant statistical correlation with air temperature or precipitation, reinforcing the notion that increasing air temperatures and precipitation are drivers of major changes in various components of the Arctic system. To progress beyond a presentation of the Arctic physical climate changes, we find a correspondence between air temperature and biophysical indicators such as tundra biomass and identify numerous biophysical disruptions with cascading effects throughout the trophic levels. These include: increased delivery of organic matter and nutrients to Arctic near‐coastal zones; condensed flowering and pollination plant species periods; timing mismatch between plant flowering and pollinators; increased plant vulnerability to insect disturbance; increased shrub biomass; increased ignition of wildfires; increased growing season CO _2 uptake, with counterbalancing increases in shoulder season and winter CO _2 emissions; increased carbon cycling, regulated by local hydrology and permafrost thaw; conversion between terrestrial and aquatic ecosystems; and shifting animal distribution and demographics. The Arctic biophysical system is now clearly trending away from its 20th Century state and into an unprecedented state, with implications not only within but beyond the Arctic. The indicator time series of this study are freely downloadable at AMAP.no.