5 February 2014 - Atmospheric CO2 At 397.89; Seasonal CO2 Amplitude Growing
ON EDIT: BTW, Scripps has daily updates (one-day lag) if you're tired of waiting around for monthly updates from NOAA/CO2Now, et.
Levels of carbon dioxide in the atmosphere rise and fall annually as plants take up the gas in spring and summer and release it in fall and winter through photosynthesis and respiration. Now the range of that cycle is growing as more CO2 is emitted from the burning of fossil fuels and other human activities, according to a study led by Scripps Institution of Oceanography, UC San Diego.
The findings are the result of a multi-year airborne survey of atmospheric chemistry called HIAPER Pole-to-Pole Observations (HIPPO). Observations of atmospheric CO2 made by aircraft at altitudes between 3 and 6 kilometers (10,000-20,000 feet) show that seasonal CO2 variations have substantially increased in amplitude over the last 50 years. The amplitude increased by roughly 50 percent across high latitude regions north of 45° N, in comparison to previous aircraft observations from the late 1950s and early 1960s.
This means that more carbon is accumulating in forests and other vegetation and soils in the Northern Hemisphere during the summer, and more carbon is being released in the fall and winter, said study lead author Heather Graven, a postdoctoral researcher in the Scripps CO2 Program led by geochemist Ralph Keeling.
It is not yet understood why the increase in seasonal amplitude of CO2 concentration is so large, but it is a clear signal of widespread changes in northern ecosystems.
“The atmospheric CO2 observations are important because they show the combined effect of ecological changes over large regions,” said Graven. “This reinforces ground-based studies that show substantial changes are occurring as a result of rising CO2 concentrations, warming temperatures, and changing land management, including the expansion of forests in some regions and the poleward migration of ecosystems.”
The study, “Enhanced seasonal exchange of CO2 by northern ecosystems since 1960,” appears in print editions of the journal Science on Aug. 30 and in Science Express Aug. 8. The National Science Foundation, the federal Department of Energy, the National Center for Atmospheric Research (NCAR), NOAA, and the Office of Naval Research funded the study.
The researchers compared recent aircraft data with older aircraft data gathered from 1958 to 1961 using U.S. Air Force weather reconnaissance flights and analyzed by Scripps geochemist Charles David Keeling, the father of Ralph Keeling. These aircraft measurements were done at the same time C.D. Keeling was beginning continuous CO2 measurements at Mauna Loa, Hawaii. While the Mauna Loa measurements are now recognized as the famous “Keeling Curve,” the early aircraft data were all but forgotten.
Carbon dioxide concentrations in the atmosphere varied between 170 and 280 parts per million over the past 800,000 years. By the time C.D. Keeling began collecting data at Mauna Loa in 1958, the concentration had risen to about 315 parts per million. In May 2013, daily CO2 measurements at Mauna Loa exceeded 400 parts per million for the first time in human history.
Recent observations aboard a modified Gulfstream V jet known as HIAPER were made during research flights conducted by NCAR with scientists from Scripps, Harvard, NOAA, NCAR, Princeton University and the University of Miami in the HIPPO campaign between 2009 and 2011. The aircraft repeatedly ascended and descended from a few hundred meters to roughly 12 kilometers (40,000 feet) between the North Pole and the coast of Antarctica to construct a unique snapshot of the chemical composition of the atmosphere. Additional recent data comes from regular flights conducted at a network of locations by NOAA. Increasing CO2 amplitude since 1960 had already been observed at two ground-based stations: Mauna Loa and Barrow, Alaska. Other stations operated by Scripps and NOAA only began measuring CO2 in the 1970s to 1990s. The aircraft-based observations uniquely show the large area in the northern high latitudes where CO2 amplitude increased strongly since 1960.
EDIT
http://keelingcurve.ucsd.edu/916/