Human Domination of Earth's Ecosystems summary

    Peter M. Vitousek, Harold A. Mooney, and Jerry M. Melillo collaborate on this article about the impacts of our accelerating dominance over the Earth's ecosystems.  Human enterprises such as agriculture, industry, fishing, and international commerce transform the land surface, altering major biological cycles and adding or removing species from ecosystems. These changes prompt further changes through a domino effect which is driving climate change and irreversible losses of biological diversity. It has been estimated that 39 to 50% of the Earth's land has been transformed or degraded by humanity. The most powerful of which is row-crop agriculture which occupies 10 to 15% of the Earth's land surface. This land transformation is the primary driving force in the loss of biological diversity.
    Humans also have a substantial impact on marine ecosystems. We use about 8% of the primary production from oceans, with 25% in upwelling areas and 35% in temperate continental shelf systems. As of 1995 22% of marine fisheries were over-exploited or already depleted, 44% were already at their limit of exploitation.
    We have also significantly altered biogeochemical cycles by addition of carbon dioxide into the atmosphere, deliberately fixing nitrogen from the atmosphere, substantial use of the worlds fresh water supply (over half) with 70% going to use for agriculture. Synthetic organic chemicals also play a major role in the alteration of biogeochemical cycles, many of them are highly toxic to humans and animals, they also tend to persist in the environment for decades.
    Recent calculations suggest that current rates of species extinction are among the order of 100 to 1000 times those before humanity's dominance over the Earth. 11% of birds, 18% of mammals, 5% of fish, and 8% of plant species are currently facing threat of extinction. Humans have also largely increased the rate of biological invasion (invasive species). These invasive species can introduce new pathogens and also can out compete some of the native species which puts further stress on the ecosystem. Our number one goal should be to try and reduce the rate at which we alter the Earth's systems, thus hopefully giving ecosystems a better chance to change and adopt.