Global warming, strictly speaking, is the observed increase of the average temperature of the ocean and the near-surface air of Mother Earth as recorded for some decades now and is being felt at present. According to the Intergovernmental Panel on Climate Change (IPCC), much of the warming of the atmosphere and large bodies of water such as oceans can probably be directly attributed to the release of greenhouse gases starting predominantly from the middle of the 20th century, which tend to accumulate and produce the greenhouse effect.

The IPCC predicts that worldwide surface temperatures are estimated to increase further by 1.1 to 6.4 degrees Centigrade by year 2100. This estimate can be affected by the ability and willingness of the present living generation of human beings to significantly cut down on greenhouse gas emissions. The problem is, even if much of the present levels of greenhouse gas emissions can be reduced, global warming is expected to still continue, perhaps even past year 2100, due to the capacity of oceans to retain absorbed heat.

Global temperatures are now causing a rise in the sea levels, more severe weather changes to be experienced, and a corresponding negative affect on precipitation amounts and behavior. As a result, human agriculture activities may have to change to match the changes in the weather, even as polar glaciers melt at an alarming rate, various species face extinction, and disease vector ranges fluctuate.

Governments are expected to play a major role in helping their citizens reduce the total greenhouse gases emitted by their country, particularly if these governments adhere to the Kyoto Protocol which many government leaders throughout the world agreed to and signed to show their intent to participate.

Global warming falls under the much more comprehensive term of climate change. Global warming is the direct opposite of global cooling, which also falls under climate change. Climate change, as used by the United Nations Framework Convention on Climate Change, is used to refer solely to climate change caused by human activities. Climate changes due to other causes falls under the term climate variability. Anthropogenic global warming is another term used to describe change caused by human activities.

The human activity which has contributed the most to the accumulation of carbon dioxide in the atmosphere would be burning of fossil fuels (a.k.a. oil and gas) for power within the last 20 years. Other human activities that have helped in the increase in warming of the global atmosphere could include deforestation, that falls under human land-use activities. If communities throughout the world persist in using fossil fuels as a power source and cutting down forests at a rapid pace without replenishing forest stocks, then it is safe to assume that global warming will continue and may even escalate in the future.