Scientists have concluded that forests with excessive nitrogen concentrations reduce the amount of carbon dioxide released into the atmosphere. During a ten year study in Michigan by the National Science Foundation, researchers intentionally fertilized forests with two to three times the current levels of nitrogen. These levels mimic the predicted nitrogen levels of the near future due to fertilizers and exhaust from cars, power plants, and factories.
“It is pretty important to recognize that human effects on the nitrogen cycle have significant effects on climate,” said Alan Townsend, North American director of the International Nitrogen Initiative.
The study reports that trees grew faster and forest floor debris broke down slower. Both of these effects mean more wood to soak up carbon dioxide from the atmosphere. The excessive nitrogen will inevitably drain into the water supply.
Excessive nitrogen in water leads to a host of problems, including diseases in humans and “dead zones” in coastal waters. Experts also say that releasing nitrogen into forests could likely cause the release of another greenhouse gas, nitrous oxide, offsetting any possible climate change benefit.
The findings will aid the construction of newer, more accurate climate models. “Now that [climate modelers] have the big fluxes down, there’s a lot of these fine-tuning things left,” said Andrew Burton of Michigan Technological University.
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