Tundra ecosystems observed to be CO<sub>2</sub>sources due to differential amplification of the carbon cycle

AbstractAre tundra ecosystems currently a carbon source or sink? What is the future trajectory of tundra carbon fluxes in response to climate change? These questions are of global importance because of the vast quantities of organic carbon stored in permafrost soils. In this meta‐analysis, we compile 40 years ofCO2flux observations from 54 studies spanning 32 sites across northern high latitudes. Using time‐series analysis, we investigated if seasonal or annualCO2fluxes have changed over time, and whether spatial differences in mean annual temperature could help explain temporal changes inCO2flux. Growing season netCO2uptake has definitely increased since the 1990s; the data also suggest (albeit less definitively) an increase in winterCO2emissions, especially in the last decade. In spite of the uncertainty in the winter trend, we estimate that tundra sites were annualCO2sources from the mid‐1980s until the 2000s, and data from the last 7 years show that tundra continue to emitCO2annually.CO2emissions exceedCO2uptake across the range of temperatures that occur in the tundra biome. Taken together, these data suggest that despite increases in growing season uptake, tundra ecosystems are currentlyCO2sources on an annual basis.

Tundra ecosystems observed to be CO₂sources due to differential amplification of the carbon cycle Journal Articles