Earth Equity News

Earth's Growing Nitrogen Threat. By Mark Clayton, CSMonitor, January 12, 2010. "While greening farms worldwide, much nitrogen washes into lakes, rivers, and the sea, causing rampant algae growth. More nitrogen billows from power-plant smokestacks, blowing in the wind until it settles as acid rain. Still other nitrogen gases remain in the atmosphere consuming the ozone layer. Nitrous oxide is nearly 300 times as potent as carbon dioxide and the third most threatening greenhouse gas overall. Last year, reactive nitrogen was identified as one of nine key global pollution threats and second worst in terms of having already exceeded a maximum 'planetary boundary,' according to a study reported in the journal Nature...

"Africa is one of a few places in the world where wider use of nitrogen fertilizers makes sense to help feed the population, many researchers agree. In the US, however, as much as 40% of reactive nitrogen is wasted -- washing off farm fields into rivers, lakes, and the ocean, where oxygen-depleted 'dead zones' are growing in number and size worldwide. The situation is even worse in China, which uses about twice as much nitrogen fertilizer as the US to yield about the same amount of crops. As much as three-quarters of all nitrogen used to grow rice in China may be wasted, says Vaclav Smil, a nitrogen expert at the University of Manitoba in Winnipeg. Vehicle exhaust, power-plant exhaust, and large-animal feeding operations are all sources of nitrogen emissions...

"Most nitrogen doesn't stay in the atmosphere the way carbon dioxide from fossil fuel does, but precipitates out within a few days. Ammonia -- a mixture of hydrogen and nitrogen - becomes ammonium when mixed with water and acts like fertilizer when it falls to the ground in rain... Researchers have spotted invasive grasses that thrive on nitrogen sprouting up in the Mojave and Sonoran deserts. Beside threatening other plant species, such grasses fuel wildfires. But the most dramatic impacts can be seen in the growth of coastal dead zones where excessive nutrients in the water -- fueled by runoff of fertilizers -- has suffocated or driven away ocean animals. In the Gulf of Mexico, fish and shrimp have been eliminated in an 8,000-square-mile dead zone at the mouth of the Mississippi River. More than 400 dead zones with a total area of 245,000 square kilometers were identified worldwide last year."