Figure 33.4

This figure appears in chapter 33 of the Climate Change Impacts in the United States: The Third National Climate Assessment report.

http://nca2014.globalchange.gov/report/appendices/climate-science-supplement/graphics/heat-trapping-gas-levels

Present-day atmospheric levels of carbon dioxide, methane, and nitrous oxide are notably higher than their pre-industrial averages of 280, 0.7, and 0.27 parts per million (ppm) by volume, respectively (left). Air sampling data from 1958 to 2013 show long-term increases due to human activities as well as short-term variations due to natural biogeochemical processes and seasonal vegetation growth (right). (Figure sources: (left) Forster et al. 2007f2b357c2-f4ae-4868-a058-e48fbdbb1303; (right) Scripps Institution of Oceanography and NOAA Earth Systems Research Laboratory).

Free to use with credit to the original figure source.

This figure was created on November 19, 2013.

Provenance

This figure was derived from Climate Change 2013: The Physical Science Basis

References :

• chapter ipcc-ar4-wg1 chapter 2 : Changes in Atmospheric Constituents and in Radiative Forcing (f2b357c2)

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