The uncertainty and controversy seemed daunting; but it's important, it seems to me, that we struggle with this issue. If we are headed in the direction most scientists predict we're headed in, we can't afford to put off starting solutions until the day when all our questions are completely answered. If we wait around until everything is absolutely clear, no controversy, it may be well too late. Some things are certain, we know that greenhouse gases trap heat in the atmosphere. We know that greenhouse gasses exist naturally and are cycled through oceans and forests. From the ice cores taken from glaciers we've been able to examine the concentration of atmospheric carbon dioxide, an important greenhouse gas over the past 400,000 years. Now, that's a long time, 400,000 years. We know that increases in carbon dioxide have always been associated with increases in temperature over that period.
In 1995, an organization of 2,500 scientists formed the intergovernmental panel on climate change, IPCC, that's a term we'll hear frequently today and in the continuing study of this matter, and this group of scientists, 2,500 of them, the IPCC issued a report summarizing the evidence gathered over the past 100 years on the greenhouse effects of carbon dioxide and other gases. They concluded there's a small but discernible human influence on global climate, and they warned that this impact may be gathering momentous. The concentration of carbon dioxide in the atmosphere has steadily increased over the past 200 years. The earth is warmed by one degree Fahrenheit over the past hundred years. It may warm another two to six degrees Fahrenheit over the next 100 years. Now, those are incredible statistics. That would be the fastest increase in temperature experienced by the species now comprising life on earth. Whether the complex ecosystems that are involved evolved over eons can adapt successfully, the change is so rapid, in other words, two to six degrees change in Fahrenheit in 100 years, can we adjust to that? It's the most important unanswered question. But we humans will face challenges as well. For instance, IPCC predicts that sea levels may rise an additional half to three-and-a-half feet in that 100 year period. All of us in Rhode Island can appreciate the significance of a result like that, an increase in sea levels of a half to three-and-a-half feet.
The bill we're considering, S.547, this morning makes only the modest beginnings on this large problem. It would encourage voluntary reductions in greenhouse gas emissions by U.S. industries by promising those industries credits for the reductions they took if a mandatory program is ever adopted. In other words, the legislation we have says if you -- we don't have any mandatory statute on the books yet about having to reduce greenhouse emissions, but some companies are willing to do it, and if voluntarily they want to do it, reduce their greenhouse emission, if subsequently legislation is enacted requiring such reductions, then the companies that have made the reductions prior thereto will get credit for it, and they're doing it voluntarily and they deserve credit for it. Now, this is a modest start, but getting a start is very important.
Carbon dioxide accumulates in the atmosphere. From the perspective of climate, the ton of carbon dioxide that we voluntarily avoid emitting today is just as important as the ton that may eventually be prevented by the Kyoto Protocol of some other mandatory program.
It may be many years before our political system responds to the threat of climate change in any meaningful way. When it does, and I, for one, am convinced that we must change our course, the reductions that have been accumulated year after year from this modest beginning will pay big dividends, and the companies that take advantage of this opportunity will realize much lower compliance costs because they had a longer period to adjust their business practices.
Now, even this modest beginning, you say who can object to that, it's voluntary, you get credit later on if you make the reductions, who can complain. Well, welcome to Washington. Even this modest beginning is not without its controversy. Everyone salutes the concept of giving credit for voluntary reductions, but, indeed, there are devils in the details. What Government agency should run the program? How do we ensure that our accounting methods only count real reductions in greenhouse gases? How do we recognize projects like reforestation or preservation that sequester carbon rather than reduce emissions? Should foreign investments count? Should we give credit to the reductions that have been made since the Rio Treaty was signed in 1982? How far back do we go?