Changes

'''Global warming''' is a phrase which commonly refers to a scientific theory and to political proposals that follow if the theory is accepted. The scientific theory is widely but not universally accepted within the scientific community. Portions are challenged, particularly by conservatives who are opposed to the political proposals that flow from acceptance of the theory and are thus properly skeptical of the motivations of the theorists. The phrase really includes three separate theories.

'''Global warming''' is a phrase which commonly refers to a scientific theory and to political proposals that follow if the theory is accepted. The scientific theory is widely but not universally accepted within the scientific community. Conservatives who are opposed to the political proposals that flow from acceptance of the theory, are properly skeptical of the motivations of the theorists, and challenge the scientific validity of portions of the theory. The phrase really includes three separate theories.

:1) The theory that we are currently in a period of rapid climate change consisting of increasing temperature, which, if it were to continue, would have important socio-economic consequences well within the next century.  

:1) The theory that we are currently in a period of rapid climate change consisting of increasing temperature, which, if it were to continue, would have important socio-economic consequences well within the next century.  

:2) The theory that this change is caused by increasing CO₂ gasses and a resulting "greenhouse" effect.

:2) The theory that this change is caused by increasing CO₂ gasses and a resulting "greenhouse" effect.

:3) The theory that this change is caused by human activity, mostly industrial emissions of carbon-based "greenhouse gasses."

:3) The theory that this change is caused by human activity, mostly industrial emissions of carbon-based "greenhouse gasses."

Therefore, the phrase has come to apply to

Therefore, the phrase has also come to apply to

:4) The proposal that global warming can and should be reversed by taking large-scale international action to reduce greenhouse emissions.

:4) The proposal that global warming can and should be reversed by taking large-scale international action to reduce greenhouse emissions.

Point #1 has become very widely accepted in the past few decades, even by conservatives who were once skeptical.

Point #1 has become very widely accepted in the past few decades, even by conservatives who were once skeptical.

Points #2 and point #3 are more controversial, although widely accepted by scientists. Points #3 is the one most attacked by skeptics.  

Points #2 and point #3 are more controversial, although widely accepted by scientists. Points #3 is the one most attacked by global warming skeptics.  

Point #4 is what the political and international debate are about. Both climate change itself, and the very large-scale actions that are proposed to combat it, would have enormous economic effects with identifiable winners and losers, resulting in an intense debate. For example, since the industrialized nations emit most of the CO₂, if it were agreed that these emissions needed to be reduced sharply, the burden would fall much more heavily on these nations than on undeveloped nations.

Point #4 is what the political and international debate are about. Both climate change itself, and the very large-scale actions that are proposed to combat it, would have enormous economic effects with identifiable winners and losers, resulting in an intense debate. For example, since the industrialized nations emit most of the CO₂, if it were agreed that these emissions needed to be reduced sharply, the burden would fall much more heavily on these nations than on undeveloped nations.