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Three Causes of Global Warming

The term "global warming" describes the rise in Earth's temperature. This occurs via the greenhouse effect, by which gases such as carbon dioxide, methane and nitrous oxide absorb infrared radiation in the form of heat and light energy from the sun. This energy is kept within Earth's atmosphere, causing a rise in temperature. The three main contributors to global warming are deforestation, meat and dairy consumption, and the burning of fossil fuels.

  1. Deforestation

    • Trees act as carbon reservoirs by absorbing carbon dioxide during photosynthesis. Deforestation disrupts the carbon cycle as less carbon dioxide is absorbed, leaving more present in the atmosphere. Also, since trees are absent, deforestation prevents future carbon storage. Deforestation also affects the water cycle, as trees recycle rainfall by extracting soil water and return it to the atmosphere. This causes a drier regional climate and increased risk of forest fires, which further contributes to deforestation.

    Fossil Fuels

    • Fossil fuels are responsible for approximately 85 percent of America's energy. Fossil fuels added approximately 25 percent of carbon dioxide to the atmosphere over the past 150 years. Methane, nitrous oxide and sulfur-containing compounds linked to acid rain also derive from fossils fuels. Although carbon dioxide contributes more to global warming, methane, nitrous oxide and sulfur hexafloride all have higher global warming potentials, meaning they are more effective greenhouse gases and have higher atmospheric lifetimes.

    Meat and Dairy

    • The meat and dairy industry contributes to approximately 18 percent of greenhouse gas emissions, more than the entire transport sector. Fifty-six billion land animals are reared and slaughtered annually, which is set to double by 2050. Animal manure adds approximately 18 million metric tons of methane to the atmosphere each year. Excess manure not used as fertilizer is disposed of in landfills, contributing to groundwater and soil pollution. Desertification due to animal farming reduces vegetative cover and causes an estimated 100 million metric tons of carbon dioxide to escape into the atmosphere annually.

    Mitigation Strategies

    • Deforestation occurs mainly because of livestock and animal feed farming, and fossil fuels used in meat and dairy production contribute approximately 130 million metric tons of carbon dioxide per year. Afforestation helps preserve carbon stores and maintain ecosystems. Deforestation in the Brazilian Amazon was reduced to 11,000 square kilometers per year due to government intervention and afforestation. Dietary changes could help lower demand for meat and dairy, thus reducing both fossil fuel and animal farm emissions.

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