Research and Application News
Earth is breathing deeper
08 August 2013
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 published in Science by Scripps Institution of Oceanography, UC San Diego, with CIRES and NOAA co-authors.
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 kilometres (10,000-20,000 feet) - combined with aircraft data from NOAA and CIRES - 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.