Kobuk River - Climate

Climate

The Kobuk River Basin is located just north of the Arctic Circle and has a continental climate. The summers are short and warm, while winters are long and cold. The mean annual temperature in the middle and upper portions of the Kobuk Valley is -6 °C, and the mean temperature in July is 15 °C. An average of 21 inches (53 cm) of precipitation falls in the basin. However, actual precipitation can range from 15-40 inches (40–100 cm) with greater amounts falling in the upper reaches of the river basin.

The Kobuk River Basin is very sensitive to changes in climate. Arctic climates have warmed at approximately twice the global rate in the last several decades. Records of air-temperature from 1961 to 1990 logged at the latitudes of the Kobuk River, show a warming trend of about 1.4 °F (0.78 °C) per decade. The warming has been the strongest in the winter and spring months. Climate change is presently considered the most severe environmental stress in the Kobuk River Basin and throughout Alaska.

As a specific example, climate change will cause widespread thawing of permafrost in the discontinuous zone and significant changes in the continuous zone. Thawing permafrost can lead to a landscape of irregular depressions (thermokarst) due to subsiding soils. This can alter drainage patterns and even change the course of streams; whereas other areas could become swamp-like. In addition, slope stability will decrease and permafrost degradation could lead to erosion of river banks resulting in an increase in sediment transport by the rivers. These physical changes will impact nutrient cycling and biological processes within the basin as well.