What Causes Global Warming?

Dutch Steel Mill

Bruce B. Clarke/Getty Images

Scientists have determined that a number of human activities are contributing to global warming by adding excessive amounts of greenhouse gases to the atmosphere. Greenhouse gases such as carbon dioxide accumulate in the atmosphere and trap heat that normally would exit into outer space.

Greenhouse Gases and Global Climate Change

While many greenhouse gases occur naturally and are needed to create the greenhouse effect that keeps the Earth warm enough to support life, human use of fossil fuels is the main source of excess greenhouse gases. By driving cars, using electricity from coal-fired power plants, or heating our homes with oil or natural gas, we release carbon dioxide and other heat-trapping gases into the atmosphere.

Deforestation is another significant source of greenhouse gases, as exposed soils release carbon dioxide, and fewer trees mean less carbon dioxide conversion to oxygen.

The production of cement involves a chemical reaction responsible for a surprisingly large amount of carbon dioxide in the atmosphere every year.

During the 150 years of the industrial age, the atmospheric concentration of carbon dioxide has increased by 31 percent. Over the same period, the level of atmospheric methane, another important greenhouse gas, has risen by 151 percent, mostly from agricultural activities such as raising cattle and growing rice. Methane leaks at natural gas wells are another major contributor to climate change.

There are steps we can take to reduce greenhouse gas emissions in our life, encourage carbon emission reduction programs, methane emission reduction laws, and we can support global climate change mitigation projects.

Can Natural Sun Cycles Explain Global Climate Change?

In short, no. There are variations in the amount of energy we receive from the sun due to factors like orbital patterns and sunspots, but none can explain the current warming, according to the Intergovernmental Panel on Climate Change (IPCC).

Direct Effects of Global Climate Change

  • Many of the effects of climate change can be tied directly to some very important changes in our atmosphere
  • Because of important gas and heat transfers between the atmosphere and seawater, a suite of changes in the oceans have been observed
  • The frozen parts of the Earth are especially vulnerable to climate change. The latest IPCC report explained the impacts on the world's polar ice caps, glaciers, and permafrost

The Consequences of Global Warming

The increase in trapped heat changes the climate and alters weather patterns, which may change the timing of seasonal natural events, and the frequency of extreme weather events. Polar ice is vanishing, and sea levels are rising, causing coastal flooding. Climate change leads to food insecurity, and even national security, concerns. Agricultural practices have been affected, including the production of maple syrup.

There are also health consequences of climate change. Warmer winters allow for range expansions of white-tailed deer and deer ticks, increasing the incidence of Lyme disease.