I have no trouble accepting the data that indicates the Earth is warming. The Earth has undergone many warming and cooling cycles over geologic history, the most recent being the Little Ice Age that lasted from 1350 to 1850, along with a much more severe ice age that ended (through global warming) about 10,000 or so years ago.

There is still legitimate debate as to the cause of the current warming cycle. Was it massive man-made CO2 emissions that ended the Little Ice Age, or was it a change in solar output. Recent evidence suggests that the Little Ice Age was caused by a decrease in solar output and ended by an increase in output. It would appear that human activity had little or no effect on that warming even through the first 50 years or so of the Industrial Revolution (which resulted in a massive increase in energy consumption) had taken place by 1850.

Even if it could be proven conclusively that man-made CO2 emissions were behind the current warming trend, the Kyoto Protocols would still be fatally flawed. For one thing, just by exempting the "developing" nations of China and India from the emissions reductions, you're eliminating over 1/3rd of the world's population. The economies in China and India are growing very rapidly and so is their energy consumption and pollution production.

A better approach is what the Bush administration has quietly been pushing - help those countries implement cleaner technology for energy production and consumption. While many of the countries that have signed on to the Kyoto Protocols are having trouble meeting their CO2 emissions targets, I saw a recent article that states that the US has actually reduced our CO2 emissions over the past few years. In the end, it's results that count more than any piece of paper, no matter how many countries have signed it.