Vegetation changes in the Arctic

This image of the day from NASA shows how the Normalized Difference Vegetation Index (NDVI), an indicator of photosynthetic activity or the “greenness” of the landscape, has changed over the past three decades (1982-2011) in the far northern latitudes of the Arctic. Rising temperatures in the Arctic are impacting the region's vegetation as described in a March 2013 publication in Nature Climate Change.

Researchers have documented that vegetation seasonality is diminishing, which means that there is an increase in plant growth. While treeless tundra ecosystems of the circumpolar Arctic were once  dominated by grasses, tall shrubs and trees have started to grow in their place. Boreal forests are also responding to a warmer Arctic; these forests showed different responses depending on whether conditions were drier (decreased photosynthesis) or wetter (increased photosynthesis) than usual.

References and related readings are available here.

Information on how scientists use remote sensing to study vegetation from space can be found here.

Video: Soil Microbes, Permafrost and Global Warming

This 4 minute video adapted from KUAC-TV and the Geophysical Institute at the University of Alaska, Fairbanks does a nice job of explaining how soil microbes in Arctic permafrost are contributing to the carbon cycle throughout the year and not just during the summer.  This video also describes how these microbes are part of a positive feedback loop: as more permafrost thaws, more microbes are active, releasing more carbon dioxide into the atmosphere, accelerating warming - the role of shrubs and snow in this feedback loop is also addressed.

This teaching resources has been approved by the Climate Literacy and Energy Awareness Network and is accompanied by a background essay as well as discussion questions.

Environmental scientist Rose Cory, PhD, is investigating how sunlight accelerates microbial activity in thawing permafrost. To learn more click here.

What we are learning about thermokarsts

Tremendous stores of organic carbon have been frozen in permafrost soils for thousands of years. A thermokarst failure is generated when these ice-rich, permanently-frozen soils are warmed and thawed, the ice melts, and the soil collapses and either creates an erosional hole in the tundra or a landslide if the slope is sufficient. An environmental chemist at UNC-Chapel Hill, Dr. Rose Cory, is studying thermokarsts in the Alaskan Arctic. Specifically, she is investigating the role of sunlight in stimulating carbon dioxide release from permafrost soil carbon. Dr. Cory's findings have revealed that thermokarsts produce significant amounts of carbon dioxide and represent a previously unrecognized store of carbon that is currently not included in future climate predictions.

Rose Cory, Ph.D. standing at a gully erosion thermokarst (hand on soil ice and thermokarst water sampled at bottom of picture).

Dr. Cory's research provides the first evidence that the respiration of previously frozen soil carbon will be amplified by reactions with sunlight (photochemical processes) and their effects on bacteria.  

To learn more about her latest research findings visit:

Slumping Arctic Soils Produce Significant Amounts of CO2.
Science NOW. Feb 11, 2013.

Surface exposure to sunlight stimulates CO2 release from permafrost soil carbon in the Arctic. Proceedings of the National Academies of Science. Feb 11, 2013.

Also available is a 5 minute video describing Dr. Cory's research and showing life in the field in the Alaskan Arctic  – this video features graduate students conducting research as well.

Trouble in the Tundra (article about Thermokarsts)
Video showing a Thermokarst (35 second video)

Walking in a thermokarst (29 second video)

Antarctica Resources from WHOI

Woods Hole Oceanographic Institution's Polar Discovery Website includes a section on Antarctica that provides an introduction to the continent, information about its location & geography, ocean circulation, and ecosystem along with useful maps and diagrams. For example, an interactive diagram showing both a summer and winter Antarctic ecosystem is available.

There is also a section titled Compare the Poles that compares the Arctic and Antarctica in terms of
their physical features, seasons, weather, frozen features, and plants & wildlife.