NEW YORK: Four of nine planetary boundaries have now been crossed as a result of human activity, says an international team of 18 researchers that includes Scripps Institution of Oceanography at UC San Diego Distinguished Climate and Atmospheric Scientist Veerabhadran Ramanathan.
These boundaries comprise climate change, alteration of biogeochemical cycles, loss of biosphere integrity and land-system change and the changes created by human activities have pushed humanity beyond a “safe operating space.”
Carpenter elaborated “We’ve changed nitrogen and phosphorous cycles vastly more than any other element.” This increase is on the order of 200 to 300 percent. In contrast, carbons have only been increased 10 to 20 percent and look at all the uproar that has caused in the climate.”
Nitrogen and phosphorous are extensively used in crop fertilization and owing to the immense increase in large-scale industrial agriculture in the last few years, the enormous usage of these chemicals are causing damage to our ecology. The high concentration of these elements is also depleting the quality of water. Phosphorous imbalance can result in harmful algal blooms which in turn may cause “oxygen dead zone.” One such zone has been recently discovered in Lake Erie. Similarly the “dead zone” in the Gulf of Mexico is believed to be the outcome of nitrogen flowing through the Mississippi River.
Carpenter said “There are places that are really, really overloaded with nutrient pollution. Wisconsin and the entire Great Lakes region are some of those. But there are other places where billions of people live that are undersupplied with nitrogen and phosphorous.” One such example is Africa which has a scarcity of both the elements. The study has been published in the journal Science.
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