Originally posted by Evil Dave
Unless you seriously want to screw with the natural cycle of global warming and cooling,
you may slow it down by a couple years, a decade at the most, but it will happen as it has before, when man was not even a factor, and when the earth was greener.
it is possible for a single organism to forever, and irriverseably change the environment (case in point: cyanobacteria 1.7bya. before them our atmosphere was reductive). so to say that no matter what the earth will continue to exhibit a stably cycling sytstem is wholely incorrect. it is possible, through our fault or not, that the atmosphere will chage dramatically resulting in an environment that is inhospitable to life as we know it. organisms tend to create a dampening effect (whereby they modify the environment around them and stabalize it. case in point: a forest has decreased temperature fluctuations), but we\'re chopping those down, so who knows?
you cite the cycles like rules in a text book, but they are not! they are a history, and many of those environmental cycles may have been (and indeed have been shown to be)caused by organisms on the planet ( and sources other than astrological forcing).
therefore the possibility that our atmosphere could be rendered (again, for whatever reason) toxic.
consider the following:
1) we produce pollutants that are known to change environments (as demonstrated in laboratory experiments , and localized geographical occurences) or otherwise toxify them. care to dispute this point?
2) we have caused continent wide environmental effects (
asian brown cloud, oil spills etc) care to dispute this point?
3) historical environmental effects have resulted in mass extinction events. care to dispute this?
4) the environment is not static (or even stably cyclic), and has experienced many, significant, planet changing effects that have influenced both the phisical and biotic aspects of the planet, permenently. example: paleozoic O2 levels were dramatically higher:
result ). here is a great quote from Dr. Dudley:
\"Uniformitarian approaches to the evolution of terrestrial locomotor physiology and animal flight performance have generally presupposed the constancy of atmospheric composition. Recent geophysical data as well as theoretical models suggest that, to the contrary, both oxygen and carbon dioxide concentrations have changed dramatically during defining periods of metazoan evolution.\"
care to dispute this?
5) we can communaly modify our behavior.
thought process: we can change the environment -> the environment can become dramatically different -> such changes may be lethal to humans. -> we may be able to alter our behavior and environmental impact
logical conclusion: we should worry about, or at least seriously consider the possibility, that we could make our planet (more) inhospitable to human life, and take some action to reduce our influence.