by Anthony Lupo (NAPSA)—One of the fundamental tenets of our justice system is one is innocent until proven guilty. While that doesn’t apply to scientific discovery, in the global warming debate the pre- vailing attitude is that human induced global warmingis already The Global Warming pari a fact of life and it is up to doubters to prove otherwise. To complete the analogy, I'll add that First, carbon dioxide is not a pollutant as many claim. Carbon dioxide is good for plant life and is a natural constituent of the atmosphere. During Earth’s long history there has been more and less carbon dioxide in the atmosphere than weseetoday. Second, they claim that climate is stable and slow to change, and we are accelerating climate change beyond natural variability. That is also not true. Climate change is generally a rr to date, there is no regional phenomenon and not a cal changes we’ve seen since the been shown to change rapidly in the past and will continue to do so credible evidence to demonstrate that the climatologimid-1800’s are outside the bounds of natural variability inherent in the earth’s climate system. Thus, any impartial jury should not come back with a “guilty” verdict convicting humanity of forcing recent climatological changes. Even the most ardent support- ers of global warming will not argue this point. Instead, they argue that humansare only partially responsible for the observed climate change. If one takes a hard look at the science involved, their assertions appear to be groundless. global one. Regionally, climate has in the future. Life on earth will adapt as it has always done. Life on earth has been shown to thrive when planetary temperatures are warmeras opposedto colder. Third, they point to recent model projections that have shown that the earth will warm as much as 11 degrees Fahrenheit over the next century. One should be careful when looking at model projections. After all, these models are crude repre- sentations of the real atmosphere and are lacking many fundamental processes and interactions that are inherent in the real atmosphere. The 11 degrees scenario that is thrown around the media as if it were the mainstream prediction is an extreme scenario. Most models predict anywhere from a 2 to 6 degree increase over the next century, but even these are problematic given the myriad of problems associated with using models and interpreting their output. No one advocates destruction of the environment, and indeed we have an obligation to take care of our environment for future generations. At the same time, we need to make sound decisions based onscientific facts. My research leads me to believe that we will not be able to state conclusively that global warmingis or is not occurring for another 30 to 70 years. We simply don’t understand the climate sys- tem well enough nor have the data to demonstrate that humanity is having a substantial impact on climate change. Anthony R. Lupo is assistant professor of atmospheric science at the University of Missouri at Columbia and served as an expert reviewer for the UN’s Intergovernmental Panel on Climate Change.