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Author Topic: Arctic carbon cycle speeding up  (Read 827 times)

ael

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Arctic carbon cycle speeding up
« on: August 07, 2018, 08:46:51 PM »
A new NASA-led study using data from the Arctic Boreal Vulnerability Experiment (ABoVE) shows that carbon in Alaska’s North Slope tundra ecosystems spends about 13 percent less time locked in frozen soil than it did 40 years ago. In other words, the carbon cycle there is speeding up — and is now at a pace more characteristic of a North American boreal forest than of the icy Arctic.

https://www.technology.org/2018/08/06/new-study-the-arctic-carbon-cycle-is-speeding-up/

bluesky

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Re: Arctic carbon cycle speeding up
« Reply #1 on: August 26, 2018, 09:40:52 PM »

Recent paper on greening of high latitude over the past 30 years, using satellite observation proxy. 16% of Earth's vegetated land where plant growth was limited by cold temperatures 30 years ago is no longer predominantly temperature-limited today. This was not properly modelled by the CMIP5 model.

Greening of the land surface in the world’s cold regions consistent with recent warming
T. F. Keenan & W. J. Riley
Nature Climate Change (2018)

https://www.nature.com/articles/s41558-018-0258-y

Abstract
Global ecosystem function is highly dependent on climate and atmospheric composition, yet ecosystem responses to environmental changes remain uncertain. Cold, high-latitude ecosystems in particular have experienced rapid warming1, with poorly understood consequences2,3,4. Here, we use a satellite-observed proxy for vegetation cover—the fraction of absorbed photosynthetically active radiation5—to identify a decline in the temperature limitation of vegetation in global ecosystems between 1982 and 2012. We quantify the spatial functional response of maximum annual vegetation cover to temperature and show that the observed temporal decline in temperature limitation is consistent with expectations based on observed recent warming. An ensemble of Earth system models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) mischaracterized the functional response to temperature, leading to a large overestimation of vegetation cover in cold regions. We identify a 16.4% decline in the area of vegetated land that is limited by temperature over the past three decades, and suggest an expected large decline in temperature limitation under future warming scenarios. This rapid observed and expected decline in temperature limitation highlights the need for an improved understanding of other limitations to vegetation growth in cold regions3,4,6, such as soil characteristics, species migration, recruitment, establishment, competition and community dynamics.


also in Science Daily:
https://www.sciencedaily.com/releases/2018/08/180821125445.htm

also on the Berkeley lab website
http://newscenter.lbl.gov/2018/08/20/ecosystems-are-getting-greener-in-the-arctic/

Would be interesting to get access to the full article which is under a paywall