Global warming is defined as the observed gradual increase in average global temperatures attributed to greenhouse gases that started in about 1850, coinciding with the industrial revolution. In addition to the measured temperature rise, the widely observed thinning of the polar ice caps, the worldwide erosion of glaciers, and the measurable rise in average land and ocean temperatures are strong supporting evidence. Two opposed camps are emerging on the matter. One view is typified by CNN's Martin O'Brien's assertion. This is the 'Al Gore camp', claiming that man's activities are dramatically and irreparably changing the climate. Its members vigorously support the principles of the Kyoto Treaty.