Carbon dioxide is safely released into the atmosphere by natural causes such as respiration and volcanic eruptions. Several human activities, however, are causing an excessive amount of carbon dioxide to be released and heavily contribute to global warming. These activities include the burning of fossil fuels, such as oil and coal, deforestation and overuse of the land.
Water vapor is the most abundant greenhouse gas. As outlined by NASA's Global Climate Change research, water vapor will increase as Earth's temperature rises because of the excess carbon dioxide. Water vapor will then respond as a "feedback" agent to the climate. This also means that gases and radiation can be absorbed and then emitted, causing a warmer atmosphere. Although most water vapor is not created by human activities, the excess greenhouse gases will result in a higher production of water vapor.
Heavy industry is responsible for much of the greenhouse gas emissions. According to the Time for Change Organization, the major types of industries or manufacturing that contribute to global warming include: power stations, transportation fuels, agriculture and their byproducts, fossil fuel processing and land use. Automobiles are a major contributor to carbon dioxide emissions, which is why many people are proponents of hybrid or electric cars for the good of the environment.
The Natural Resources Defense Council (NRDC) states that global warming has already had many negative effects on the planet and will continue to do so if human activities do not change. These ramifications include an increase in wildfires, melting glaciers and rising sea levels that can lead to flooding or a water shortage, and the disruption of habitats that leads to extinction of plants or animals.