Many Factors Combine to Affect Biogeochemical Cycles

Figure 15.4

University of Virginia
James Galloway

This figure appears in chapter 15 of the Climate Change Impacts in the United States: The Third National Climate Assessment report.

http://nca2014.globalchange.gov/highlights/report-findings/ecosystems-and-biodiversity/graphics/many-factors-combine-affect

Top panel shows the impact of the alteration of the carbon cycle alone on radiative forcing. The bottom panel shows the impacts of the alteration of carbon, nitrogen, and sulfur cycles on radiative forcing. SO₂ and NH₃ increase aerosols and decrease radiative forcing. NH₃ is likely to increase plant biomass, and consequently decrease forcing. NO_x is likely to increase the formation of tropospheric ozone (O₃) and increase radiative forcing. Ozone has a negative effect on plant growth/biomass, which might increase radiative forcing. CO₂ and NH₃ act synergistically to increase plant growth, and therefore decrease radiative forcing. SO₂ is likely to reduce plant growth, perhaps through the leaching of soil nutrients, and consequently increase radiative forcing. NO_x is likely to reduce plant growth directly and through the leaching of soil nutrients, therefore increasing radiative forcing. However, it could act as a fertilizer that would have the opposite effect.

Free to use with credit to the original figure source.

This figure was created on March 20, 2014.

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