text: The world stands on the verge of committing itself to limits on the emission of carbon dioxide that would drastically reduce the use of fossil fuels. If this fateful decision is made, the economies of developed nations will be strangled. Human prosperity will be reduced. Our ability to solve pressing problems, both human and environmental, will be severely limited. We have been told that these shackles must be imposed to forestall a hypothetical global warming projected to occur some time in the distant future. But to date the only unambiguous evidence for planetary warming is a modest rise in temperature (less than one degree Celsius) that falls well within the range of natural variation.