Publication Date:
2013-08-10
Description:
Seasonal variations of atmospheric carbon dioxide (CO2) in the Northern Hemisphere have increased since the 1950s, but sparse observations have prevented a clear assessment of the patterns of long-term change and the underlying mechanisms. We compare recent aircraft-based observations of CO2 above the North Pacific and Arctic Oceans to earlier data from 1958 to 1961 and find that the seasonal amplitude at altitudes of 3 to 6 km increased by 50% for 45 degrees to 90 degrees N but by less than 25% for 10 degrees to 45 degrees N. An increase of 30 to 60% in the seasonal exchange of CO2 by northern extratropical land ecosystems, focused on boreal forests, is implicated, substantially more than simulated by current land ecosystem models. The observations appear to signal large ecological changes in northern forests and a major shift in the global carbon cycle.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Graven, H D -- Keeling, R F -- Piper, S C -- Patra, P K -- Stephens, B B -- Wofsy, S C -- Welp, L R -- Sweeney, C -- Tans, P P -- Kelley, J J -- Daube, B C -- Kort, E A -- Santoni, G W -- Bent, J D -- New York, N.Y. -- Science. 2013 Sep 6;341(6150):1085-9. doi: 10.1126/science.1239207. Epub 2013 Aug 8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA. hgraven@ucsd.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23929948" target="_blank"〉PubMed〈/a〉
Keywords:
Arctic Regions
;
Atmosphere/*chemistry
;
*Carbon Cycle
;
Carbon Dioxide/*chemistry
;
*Ecosystem
;
Oceans and Seas
;
Seasons
;
*Trees
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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