New Arctic Lakes Could Soon Be a Major Source of Atmospheric Methane

Bubbles, bubbles, and more bubbles, in a steady stream. Many lakes in the boreal regions of Alaska are emitting methane, the product of decomposing organic matter left over from the Ice Age. Thawing permafrost has caused areas of land to slump and fill up with water, creating these bodies of water called thermokarst lakes. The water then exacerbates the thawing, expanding the size of the lake and producing even more methane. In the early cold season, ice covers the lakes and traps methane in large pockets just beneath the surface. University of Alaska Fairbanks scientists working as part of NASA’s Arctic boreal Vulnerability Experiment (ABoVE) find and measure the methane gas in these pockets seep-by-seep and lake-by-lake. ABoVE combines precise methane measurements from individual lakes with satellite data that can monitor lakes like these across the Arctic, to accurately model how much methane sub-lake seeps are adding to the atmosphere. For more on the bubbling lakes: https://blogs.nasa.gov/earthexpeditions/2016/08/23/mapping-methane-in-a-bubbling-arctic-lake/Complete transcript available. The Arctic Boreal and Vulnerability Experiment (ABoVE) covers 2.5 million square miles of tundra, forests, permafrost and lakes in Alaska and Northwestern Canada. ABoVE scientists are using satellites and aircraft to study this formidable terrain as it changes in a warming climate. Remote sensing by itself is not enough to understand the whole picture, so teams of researchers will go out into the field to gather data. With support from NASA’s Terrestrial Ecology Program, ABoVE researchers investigate questions about the role of climate in wildfires, thawing permafrost, wildlife migration habits, insect outbreaks and more. ABoVE scientist Chip Miller provides a brief introduction to the CARVE tower, which monitors the atmosphere all year round. For more on the CARVE tower: https://blogs.nasa.gov/earthexpeditions/2016/07/14/tower-power-measuring-carbon-in-the-last-frontier/Complete transcript available.

GEOS-5 simulated average column concentrations of CO2 and CO for one year. Carbon exists in many forms—e.g., carbon dioxide (CO2), carbon monoxide (CO)—and continually cycles through Earth’s atmosphere, ocean, and terrestrial ecosystems. This visualization, created using data from the 7-km GEOS-5 Nature Run model, shows average column concentrations of atmospheric CO2 (colored shades) and CO (white shades underneath) from January 1, 2006 to December 31, 2006.CO2 variations are largely controlled by fossil fuel emissions and seasonal fluxes of carbon between the atmosphere and land biosphere. For example, dark red and pink shades represent regions where CO2 concentrations are enhanced by carbon sources, mainly from human activities. During Northern Hemisphere spring and summer months, plants absorb a substantial amount of CO2 through photosynthesis, thus removing CO2 from the atmosphere. Atmospheric CO, a pollutant harmful to human health, is produced mainly from fossil fuel combustion and biomass burning. Here, high concentrations of CO (white) are mainly from fire activity in Africa, South America, and Australia. Scientists use model output data such as these to help answer important questions about Earth’s climate and to help design future satellite missions.These model simulations use fossil fuel emissions estimates provided by the Emissions Database for Global Atmospheric Research (EDGAR). NASA’s Quick Fire Emissions Dataset (QFED) estimates fire emissions using MODIS fire radiative power observations. Additional, observationally constrained estimates of CO2 flux between the atmosphere and land and ocean carbon reservoirs were produced as part of NASA’s Carbon Monitoring System Flux Pilot Project (http://carbon.nasa.gov/cgi-bin/cms/inv_pgp.pl?pgid=581). Land biosphere fluxes come from the Carnegie-Ames-Stanford Approach Global Fire Emissions Database (CASA-GFED) model which incorporates MODIS vegetation classification and AVHRR Normalized Difference Vegetation Index (NDVI) data. Ocean fluxes are produced by the NASA Ocean Biogeochemical Model (NOBM) which incorporates MODIS chlorophyll observations.