As the world's expanding population burns large quantities of fossil fuels and simultaneously cuts down large expanses of forests worldwide, the concentrations of CO2 and other greenhouse gases are building up in the atmosphere. "The green house effect is the (imperfect) analogy used to explain the atmospheric phenomenon that keeps our planet warm enough to sustain life." There is mounting evidence that this shift in Earth's atmosphere will lead to global changes and potentially major climatic disruptions . The major concern is not that the greenhouse effect is real;"we wouldn t be here if it wasn t." It s that it "may be exacerbated by anthropogenic increases in the effective gasses, threatening a disruption to the equilibrium between incoming and outgoing energy, and a resulting average global warming." From 1880 to today, by many measurements, the global average temperature has increased by 0.5 Degrees Celsius. Human and ecological systems are already vulnerable to a range of environmental pressures, including climate extremes and variability. Global warming is likely to amplify the effects of other pressures and to disrupt our lives in numerous ways. "Melting icebergs and expanding oceans may cause floods." The Intergovernmental Panel on Climate Change (IPCC) predicts that there will be an increase in sea level by the year 2100 of 1.5 feet . "Twenty Five percent of the world s population lives less than 1.1 meters above see level." The IPCC also predicts that there will be " droughts, heat waves, expanding deserts, ecosystem disruption and increasingly severe weather", as well as the productivity of agriculture, which are among the probable consequences of climate change.

There is a huge conflict over the costs of addressing the greenhouse gas problem. "There appears to be a general agreement that energy efficiency is the wave of the future." Many in the environmental community see the benefits as high and the costs of mitigation as low. Others, including some in the business community, see the benefits as low and the costs as high . "One argument states that the efficiency could reduce carbon dioxide emissions by sixty percent over the next 20 years and save money; but another claims that a reduction of twenty percent below 1990 levels would cause a drop in the U.S. Gross Domestic Product by 1 to 2 percent".

"As great as the challenge of reducing carbon dioxide emissions in the industrialized world is, the challenge of reductions in the rapidly industrializing developing countries is huge." By the year 2030, China is expected to be the largest emitter of carbon dioxide in the world . We cannot address climate change without an international framework.. If a ton of carbon were emitted in the United States and a ton of carbon were emitted in China, both would have the same effect on the climate in Washington, DC. Only through the concerted actions of all the countries of the world, developed as well as less developed, will the problem of global climate change be meaningfully addressed.

The solutions to the problems lie in developing an understanding of and a respect for that ecosystem as well as providing people with mechanisms to express that understanding in their daily choices. Each individual's perception of what, if anything, to do is strongly influenced by personal values, experience, education , training, and outlook in how to cope with uncertainty. These personal variations affect one's definition of the issue, and the weight one gives possible approaches to it. This is not just stating the obvious that economists, lawyers, biologists, atmospheric scientists, and others bring different expertise to the issue, or that optimists and pessimists can see the same glass as half full and half empty; this is highlighting the fact that the magnitude of uncertainty emphasizes those differences that would apply even if the facts concerning global climate change were undeniable.

Even if the human-caused emissions of greenhouse gases were to stop right now, it would take hundreds of years for the atmosphere to return to its pre-industrial

form. In the meantime, global climate change would likely continue.

We can slow down the rate of atmospheric change by cutting back on the amount of greenhouse gases we pour into the air. This will require a considerable change in our fuel consumption, industrial practices and lifestyles . But it's definitely worth the effort because a slow alteration in global climate would be much easier to adapt to than a fast one.

Uncertainties about global warming are so great that it is not possible now to say whether the net result has been, or will be, beneficial or harmful to forest growth and composition or to the subsequent management and use of forest resources. The only certainties are that: greenhouse gases are accumulating; that the greenhouse effect is real; and that some future global warming is possible as a result.