Seeing as I have already been in trouble for replying to the wrong person's message today, I've started a new thread as while it relates to the current discussions, I suspect that it is different enough to offend both "sides".
While I am probably as far from a nature nazi as anyone, I am firmly of the opinion that the earths climate and temperature are changing and would cite the 1970s breakup of the Miller Shelf, 1980's breakup of the Woodie Shelf, 1995 break-up of the Larson-A ice shelf and ongoing break-up of the Larson B, Wilkins and Anderson Ice shelves in Antarctica, together with the first rain in the coastal Atarctic regions in at least the Holocene (last 10,000 years) as moderately strong evidence suggesting a somewhat warmer climate. It should be noted that the shelves which are breaking up are 25,000 to 250,000 years old and have a thickness of more than 200m.
Given the pattern of hot and cold during the preceding 200,000 years, a warmer earth is probably a good thing, and if (unproven but probable) this warming is related to human activity then we have probably done ourselves a favor. But there can be too much of a good thing. While we have limited knowledge of CO2 effects on the atmosphere we do know that those changes were at least partly related to human activity. We also know that antarctic plankton mass is decreasing at a horrendous rate, and that this will impact many factors of life on earth - and given the small number of whales left, not even a president Reagan would be able to blame them for this... So while I am definitely not in favour of a retreat into an agrarian abandonment of technology, after all, if there is a problem, the only solution will be from science and technology, I believe we should be doing exactly what responsible scientists are doing: monitoring the situation, developing better models, examining alternates to some of our more impactful technologies and carrying on with life.
To my mind, and what I was referring to initially, was the "low-temperature waste heat" (i.e. not economically viable to use) energy we release into the atmosphere in vast quantities. Bear in mind, that given current economic and technical factors and our reliance on heat-engines to maintain our civilizations, that we release between 60% and 80% more energy directly into our environment than we actually get to use.
If we could for example use some new energy source, for example ZPE or fusion today, without coming up with a way of getting heat off planet, and if we used it at the same efficiencies as we are currently achieving, I would be seriously concerned. The earth has a massive thermal capacity, but Boltzmann tells us that it has a limited ability to radiate heat - in fact, we have an ongoing thermal gain courtesy of solar energy. In the last 150 million years or so a huge amount of that ongoing thermal gain has been trapped in the form of chemical energy. So it seems reasonable to assume that we are impacting the thermal balance of the earth when we release it as heat. The ongoing release of thermal energy is worrying, the discovery of new cost-efficient means of creating additional thermal energy, without a way of recapturing it or radiating it has to be of long-term interest to any scientist.
For those who think that this places me in the "eco-nazi" camp, one of the books I recommend is "The Resourseful Earth" by Julian Simon and Herman Kahn (ISBN 0-631-13467-0) (1984). Sub-titled "A response to 'Global 2000'" it resoundingly refutes most of the nay-sayers and prophets of doom. I would like to quote a passage from Bernard Cohen (who wrote a section on Nuclear Power for the book). "However, in the last 10 years science has come under irrational attack from the forces of ignorance, and is losing public support. This process has essentially destroyed the key ingredient needed to provide our bright future - nuclear power, and is already zeroing in on other targets vital to our future. Our government's science and technology policy is now guided by uninformed and emotion-driven public opinion rather than by sound scientific advice. Unfortunately, this public opinion is driven by the media, a group of scientific illiterates drunk with power, heavilly influenced by irrelevant political ideologies, and so misguided as to believe that they are more capable than the scientific community of making scientific decisions. As a result our resources are being poured down rat-holes [TheHermit suggests that ethanol from corn is a good example], and scientific endevours vital to our future are being blocked [TheHermit points at particle research, the space programs, HST, genetic engineering and food irradiation as a few examples]."