There is no shortage of news about pro-technology advocates who suggest that technology will solve our environmental problems, implicitly assuring us that we won't need to make any lifestyle changes in order to reverse global warming.

Last week at the G8 summit in Scotland, President Bush placed his hopes in new technologies to address environmental problems; anything else might harm the economy. (Recall George Bush Sr., who proclaimed back in 1992 at the Earth Summit in Rio de Janeiro that "The American Way of Life is not negotiable." Like father, like son?)

In the same vein, a Newsweek article in the run-up to the summit analyzed the opposing positions held by the Bush and Blair governments, pitting "technology optimists" versus "environmental pessimists."

In the article, technology advocates discount warnings about global warming, arguing that advances in technology have proven the environmental pessimists wrong before. As examples they give the green revolution, providing abundant and cheap food for growing populations, and the boom in oil exploration that resulted in decades of cheap energy after the oil shortages of the 1970s.

These examples are not reassuring. With the benefit of hindsight, they are short-term fixes rather than sustainable long-term solutions. The green revolution was essentially the precursor of today's factory farming, where fertilizers and pesticides, used liberally to maximize crop yields, wind up in our rivers and aquifers. And new oil exploration techniques have only postponed the inevitable end of oil and removed the incentive to develop viable long-term replacements, which may take decades to bring online. (For yet another example of an unsustainable technological solution, recall how we currently "dispose" of nuclear waste.)

In a world awash in pro-technology hype, a small dose of pessimism helps put the promises of the technology optimists into perspective.