The Effects of Population Growth on Land Use
In an article in Yale University’s Environment 360, Jonathan Foley, Director of the Institute of the Environment, University of Minnesota, argues that the global community now faces a “crisis in land use and agriculture that could undermine the health, security, and sustainability of our civilization.” While climate change has received enormous attention (rightfully, Foley argues), human population growth, and the corresponding rising global demand for meat and dairy products, rising energy prices, and the growing need for bioenergy from corn, sugarcane, and other sources ”are putting tremendous pressure on the world’s resources.” With 70 million new people per year, Foley argues, “if we want any hope of keeping up with these demands, we’ll need to double, perhaps triple, the agricultural production of the planet in the next 30 to 40 years.”
Foley said meeting the agricultural needs of a growing global population is difficult enough, but, at the same time, countries must meet growing food production needs while mitigating the effects of agricultural production on land-based ecosystems. "Already, we have cleared or converted more than 35 percent of the earth's ice-free land surface for agriculture, whether for croplands, pastures or range lands. In fact, the area used for agriculture is nearly 60 times larger than the area of all of the world's cities and suburbs. Since the last ice age, nothing has been more disruptive to the planet's ecosystems than agriculture."
Agricultural puts pressure on lands, but also on water systems. "Across the globe, we already use a staggering 4,000 cubic kilometers of water per year, withdrawn from our streams, rivers, lakes and aquifers. Of this, 70 percent is used for irrigation, the single biggest use of water, by far, on the globe. As a result, many large rivers have greatly reduced flows and some routinely dry up. And the extraction of water from deep groundwater reserves is almost universally unsustainable, and has resulted in rapidly declining water tables in many regions of the world. Future water demands from increasing population and agricultural consumption will likely climb between 4,500 and 6,200 cubic kilometers per year, hugely compounding the impacts of climate change, especially in arid regions."
Not only are water and land resources put under stress, but current agricultural practices create pollution. "Agriculture, particularly the use of industrial fertilizers and other chemicals, has fundamentally upset the chemistry of the entire planet. Already, the use of fertilizers has more than doubled the flows of nitrogen and phosphorus compounds in the environment, resulting in widespread water pollution and the massive degradation of lakes and rivers. Excess nutrient pollution is now so widespread, it is even contributing to the disruption of coastal oceans and fishing grounds by creating hypoxic "dead zones," including one in the Gulf of Mexico." Another form of pollution results from current agricultural and land use practices: C02 emissions. According to Foley, current practices, including clearing forests for agricultural land, contribute 30 percent of the currently unsustainable C02 emission levels.
Foley points to a few possible solutions: invest in "revolutionary" agricultural practices, a new "greener" agricultural revolution; and improve agricultural production while also mitigating environmental impacts. Foley says there is room for hope. "In recent years, for example, U.S. farmers — working with agricultural experts — have dramatically improved practices in the corn and soybean belt, cutting down on erosion, nutrient loss, and groundwater pollution, even as yields have continued to increase."
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