At the moment this is the certain knowledge that global warming is fact, that it is man made, a threat to our existence and reversible. As a consequence we take actions that are wasteful and counterproductive and forego others that should be taken.

But the experts are far from unanimous in supporting these assumptions.

The undisputed melting of the north polar icecap and recession of most glaciers may not imply worldwide warming; that such warming is man made is principally supported by its supposed acceleration during the industrial age; that it threatens our existence by raising the sea level and disrupting agriculture is wholly speculative; and finally, even if all these assumptions are really true it is quite unknown if reducing carbon dioxide emissions to the extent necessary would not do more harm than good to our living standard.

As a result of our discovery of the ozone hole over the Antarctic we incurred significant cost by phasing out fluorocarbons without regard to the unlikelihood of tropospheric fluorocarbons migrating to the stratosphere and its unproven interference there with ozone formation by interaction of stratospheric oxygen with sunlight. So the ozone hole is still there for without sunlight in the winter there can be no ozone generation.

Who was the famous person who wisely said that "it ain't what we don't know what will harm us, but what we know that ain't so"?