Shrub expansion may reduce summer permafrost thaw in Siberian tundra

Tundra in the rain: differential vegetation responses to three years of experimentally doubled summer precipitation in Siberian shrub and Swedish bog tundra.

Precipitation amounts and patterns at high latitude sites have been predicted to change as a result of global climatic changes. We addressed vegetation responses to three years of experimentally increased summer precipitation in two previously unaddressed tundra types: Betula nana-dominated shrub tundra (northeast Siberia) and a dry Sphagnum fuscum-dominated bog (northern Sweden). Positive resp...

Spatial and temporal variation in thaw depth in Siberian tundra near Tiksi

Siberian tundra is characterised by permafrost overlaid with an active layer. The spatial and temporal variation in the thaw depth in the active layer may play an important role in biological and hydrological processes. In this study, we carried out field investigations of flat tundra and a hillslope in a watershed near Tiksi, Siberia, at various scales, from 1997 to 2000. The ground started to...

Reindeer grazing increases summer albedo by reducing shrub abundance in Arctic tundra

Previous studies have shown that climate warming is causing shrub cover to increase at high latitudes. Increased shrub cover generally lowers surface albedo, which results in higher energy absorption and further warming. In parts of Fennoscandia, herbivory is known to control vegetation height and abundance, and thus preventing this positive feedback. Here, we combine field measurements of albe...

Permafrost thaw and destabilization of Alpine rock walls in the hot summer of 2003

Long-term CO2 production following permafrost thaw

Thawing permafrost represents a poorly understood feedback mechanism of climate change in the Arctic, but with a potential impact owing to stored carbon being mobilized1–5. We have quantified the long-term loss of carbon (C) from thawing permafrost in Northeast Greenland from 1996 to 2008 by combining repeated sediment sampling to assess changes in C stock and >12 years of CO2 production in inc...