In terms of the effects of climate change, the future is becoming increasingly clear. The expected greenhouse gas emissions scenario developed by the Intergovernmental Panel on Climate Change (IPCC) portends a world in which people and nations will be threatened by massive food and water shortages, devastating natural disasters, and deadly disease outbreaks. No foreseeable political or technological solution will enable us to avert many of these climatic impacts even if, for instance, the United States were in the near future to enter into an international carbon cap-and-trade system. Meanwhile, a technological breakthrough that would lead to a decisive, near-term reduction in the concentration of carbon dioxide (CO 2) in the atmosphere remains far away.
In addition, this scenario assumes that climate change does not trigger any significant positive feedback loops (e.g., the release of CO 2 and methane from thawing permafrost). Such feedback loops would multiply and magnify the impacts of climate change, creating an even more hostile environment than the one projected here. Thus, it is not alarmist to say that this scenario may be the best we can hope for over roughly the next 30 years. It is certainly the least we ought to prepare for.
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