I teach chemistry at the college level. One of the pieces of information that I show my students is the temperature data obtained from the Vostok ice cores, which span 400,000 years. They indicate that Antarctica saw some pretty dramatic changes in temperature long before human influence was possible. You mention that "humans have created the problem (at least in part)" ("The Melting Point," July/ August). How much does "in part" really mean? Ken Overway
My vocational background is in meteorology and climate-change research. Your descriptions of climate change seem truthful, if slightly dramatized. But I was surprised at the following statement: "We have the technology and know-how to slow, stop, and reverse global warming."
Where have you learned of a technology to stop and reverse an entire climate process? I would love to share your conviction. Rebecca Kyle
Author Paul Rauber replies: The Vostok ice cores demonstrate wide natural variation in global temperature over time. Yet the consensus of the scientific community is that the dramatic warming we are now experiencing isat least in partdecidedly unnatural. The 2001 Third Assessment Report of the United Nations Intergovernmental Panel on Climate Change cites "new and stronger evidence that most of the observed warming of the last 50 years is attributable to human activities," primarily the burning of fossil fuels. The IPCC does not pretend to be able to discern exactly how much of the warming is caused by human activities, however, nor do I.
The Third Assessment mentions solar and wind power as technologies that could help to curb global warming. Increasing the fuel efficiency of our automobiles would also contribute to reducing the atmospheric burden of carbon dioxidenow the greatest it has been in at least 420,000 years. Common prudence dictates that we do what we can to cool the planet, even in the absence of absolute proof.
The July/August issue included a cartoon page, "Creative Science," apparently intended to ridicule proposed technological approaches to addressing the problem of global warming. The first cartoon depicts a University of Houston proposal to collect solar energy on the moon and beam it back to Earth via microwaves. This idea, and related concepts using space platforms in Earth orbit, should be greeted with enthusiasm, not mockery. The people behind these projects seek a future in which we are not dependent on polluting sources of energy. They know that we desperately need to devise a new energy mix, in which solar-power satellites could be just one component.
The space solar-power concept has been around for over 30 years, and fossil-fuel corporations have fought it almost from the beginning. It will continue to experience resistance and will take decades to come to fruition. But I believe it is a development worth supporting for the benefit of future generations. James A. Vedda
BETWEEN THE LINES
Theres a clear political message implicit in your July/August issue: In a world where corporations and dictators have so often followed the classic strategy of "divide and conquer," it is imperative for environmentalists and other people of good will to adopt a counterstrategy of "unite and resist." And whatever our religious preferences, environmentalists might do well to imitate Michael Soulés practice of Buddhist compassion, even toward our apparent enemies, as a way of fostering the united action thats necessary. Andy Feeney
A photo caption on page 29 of the July/August issue stated that Alaskas Hubbard Glacier calves into Glacier Bay. It actually flows into Disenchantment Bay, at the head of Yakutat Bay.
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