Naively with agricultural pollution I was only worrying about rivers and oceans. Accidental fertilization damages forests and national parks such as the Great Smoky Mountains. Note that the Great Smoky Mountains are upstream of farms.
Cambridge, Mass. – October 10, 2013 – Thirty-eight U.S. national parks are experiencing “accidental fertilization” at or above a critical threshold for ecological damage, according to a study published in the journal Atmospheric Chemistry and Physics and led by Harvard University researchers. Unless significant controls on ammonia emissions are introduced at a national level, they say, little improvement is likely between now and 2050.
Ammonia fertilizer damages natural ecosystems.
The environmental scientists, experts in air quality, atmospheric chemistry, and ecology, have been studying the fate of nitrogen-based compounds that are blown into natural areas from power plants, automobile exhaust, and—increasingly—industrial agriculture. Nitrogen that finds its way into natural ecosystems can disrupt the cycling of nutrients in soil, promote algal overgrowth and lower the pH of water in aquatic environments, and ultimately decrease the number of species that can survive.
Totally news to me: The stuff comes in the air and is toxic to lichens and hardwood trees.
In Eastern temperate forests, like those in Great Smoky Mountains National Park, the most sensitive elements of the ecosystem are the hardwood trees, which start to suffer when nitrogen deposition reaches approximately 3 to 8 kilograms per hectare, per year. According to the new study, the actual rate of deposition—13.6 kg/ha/yr—far exceeds that threshold. In the forests of Mount Rainier National Park, it’s the lichens that suffer first; their critical load is between 2.5 and 7.1 kg/ha/yr, and the deposition rate there is at a troubling 6.7 kg/ha/yr.
What would help? No more human population growth. But that's not going to happen. I expect natural selection will boost human fertility.
Would will help eventually: The development of perennial grain crops that fix nitrogen from the atmosphere. Like Alfalfa they would not need ammonia fertilizer and therefore their use would reduce ammonia pollution.
|Share |||Randall Parker, 2013 October 17 09:39 PM|