The cold, wet climate of the Arctic has led to the extraordinary preservation of archaeological sites and materials that offer important contributions to the understanding of our common cultural and ecological history. This potential, however, is quickly disappearing due to climate-related variables, including the intensification of permafrost thaw and coastal erosion, which are damaging and destroying a wide range of cultural and environmental archives around the Arctic. In providing an overview of the most important effects of climate change in this region and on archaeological sites, the authors propose the next generation of research and response strategies, and suggest how to capitalise on existing successful connections among research communities and between researchers and the public.

Growing season conditions are widely recognized as the main driver for tundra shrub radial growth, but the effects of winter warming and snow remain an open question. Here, we present a more than 100 years long Betula nana ring‐width chronology from Disko Island in western Greenland that demonstrates a highly significant and positive growth response to both summer and winter air temperatures during the past century. The importance of winter temperatures for Betula nana growth is especially pronounced during the periods from 1910–1930 to 1990–2011 that were dominated by significant winter warming. To explain the strong winter importance on growth, we assessed the importance of different environmental factors using site‐specific measurements from 1991 to 2011 of soil temperatures, sea ice coverage, precipitation and snow depths. The results show a strong positive growth response to the amount of thawing and growing degree‐days as well as to winter and spring soil temperatures. In addition to these direct effects, a strong negative growth response to sea ice extent was identified, indicating a possible link between local sea ice conditions, local climate variations and Betula nana growth rates. Data also reveal a clear shift within the last 20 years from a period with thick snow depths (1991–1996) and a positive effect on Betula nana radial growth, to a period (1997–2011) with generally very shallow snow depths and no significant growth response towards snow. During this period, winter and spring soil temperatures have increased significantly suggesting that the most recent increase in Betula nana radial growth is primarily triggered by warmer winter and spring air temperatures causing earlier snowmelt that allows the soils to drain and warm quicker. The presented results may help to explain the recently observed ‘greening of the Arctic’ which may further accelerate in future years due to both direct and indirect effects of winter warming.

The degradation of archaeological wood at freezing and thawing temperatures is studied at the site of Qajaa in West Greenland through a combination of environmental monitoring, measurement of oxygen consumption and microscopy of wood samples. Permanently frozen wood is still very well preserved after 2–4000 years, while wood samples that thaw every summer show attack by soft rot and an average density loss of 0.1 g cm^–3 (corresponding to 25% of the dry mass) over the past 27 years. Future increases in temperature may increase the decay rate significantly (Q₁₀ = 4.2 at 0–10°C) but the effects on site depend on local hydrology.

Climate change may accelerate the degradation of archaeological sites in the Arctic and lead to a loss of important historical information. This study assesses the current preservation conditions and the processes controlling the physical and chemical stability of the Qajaa kitchen midden in western Greenland. Currently, the site is well protected by low ground temperatures, permafrost and a high water/ice content, keeping the deposits anoxic. Based on 5 years of monitoring data, degradation experiments and model simulation, our results suggest that the combined effects of permafrost thaw, thermal and hydrological erosion and oxygen exposure may lead to substantial loss of archaeological evidence before the end of the 21st century.