Yonoz said:
1) Species coevolve with each other and their environment. Like the insects and the flower-bearing plants, like us and our intestinal residents. We are all interdependent. What affects our environment affects us indirectly, and we usually discover it only when it's really bad.
Yes, and that has happened as long as life has existed on the planet. But, how do you define "bad?" If by "bad" you mean that survival of humans is reduced, then that's an anthropocentric view. Why would it be bad for the planet to change otherwise? Would it be bad for new species that can survive a changing climate to appear and take over the niches opened up by those that couldn't survive?
EDIT: The more species differentiate to suit themselves to a specific environment, the more fragile they are to changes. That is why cockroaches are said to survive the next ecological disaster while humans will not. So for example, animals that require a very narrow temperature range to produce a certain sex of offspring, may become extinct if the temperature in their ecosystem goes outside that range over a relatively short amount of time. So while the mean global temperature may change by one degree, a certain ecosystem may be worse affected, and a one-degree change in the mean global temperature will have caused one ecosystem's foodchain to be one piece short.
Species adapted to a very narrow niche have always been doomed by very small changes. And, if other species are equally narrow in their needs that the loss of that species leads to their loss as well, yes, that's all very natural and expected. The generalists survive far better in the long run and adapt to those changes. Others that have been competed out of those niches by species currently in them, but that can survive in those niches can also move in once their competitors become extinct. That is all part of evolutionary processes.
That will come at a great price. Isn't it preferable to keep the environment as stable as possible for as long as possible?
Why? Again, the planet has survived mass extinctions in the past, so even if that were to be the outcome, it doesn't mean all species will be killed off and that the gaps won't be filled in over time. Even the most seemingly inhospitable parts of our planet (from a human perpsective) have organisms living in them. Just look at the myriad species that CAN survive the temperature extremes and dry climate of the deserts. If the deserts expanded, they'd have more territory to expand into as well. If there weren't other species at the edges of their territory waiting to gobble them up, perhaps some would expand further outward into more temperate climates.
The fear-mongers would have you believe that if we allow global warming to continue, the planet will be a completely lifeless wasteland (though, even if that were to happen, we won't be around to know or care either), but there's really no reason to believe that will be true. There are numerous species that can already survive extreme environments, and already have complete ecosystems isolated within those environments that can take advantage of the changes to expand their ranges.
Was there something wrong with the planet before humans existed? Was there something wrong with the planet when the atmosphere was mostly carbon dioxide, methane and ammonia? Life came to exist in that environment, and the presence of living organisms is what is hypothesized to have changed the atmosphere into the oxidizing one we have now so that the life forms we currently have were able to come into existence and survive. So, why is it bad if the planet reverts back to that state? In the grand scheme of the universe, why does life need to exist on this planet at all? Was the planet a bad place when cavemen only existed in a few places, and didn't have the ability to modify the environment to expand the range of humans globally? Would it be a bad planet if we were no longer able to control our environment and instead, humans once again had their ranges limited by environmental conditions? Would it really be a bad thing if humans could no longer live in equatorial regions, or in deserts, and had to move closer toward the poles because that was the more temperate climate? Is there much difference in being excluded from an environment due to extreme cold vs extreme heat?
As with all species, we have a selfish interest for survival in the present. We want nutrients, and we want to reproduce. But, we only delude ourselves if we think we can keep the environment from changing hundreds, thousands or millions of years into the future.
How do we even know what's best for preserving the environment if we want to do so? For decades, people tried to prevent forest fires, we still do. But, then comes up evidence that forest fires are actually important for the survival of species in the forest, and not destructive as we thought. Seeds wouldn't sprout on forest floors covered with thick layers of decomposing leaf litter, and seedlings can't get enough sunlight to thrive under a thick forest canopy, and the animals that feed off those seedlings, or nest in the underbrush were running out of habitat. Again, it just shows our arrogance at thinking we can keep things from changing without those acts themselves harming the environment. Change is always occurring, and trying to resist change is often more harmful in the bigger picture than allowing it to happen.
Since it's really all "what if" scenarios, I'll pose one that I doubt many environmentalists think about. What if we can't stop global warming...maybe we can slow it, maybe we have no impact at all because it's just too late, whether it was our fault or not, but regardless of who or what is to blame, it's happening and is irreversible. Now, in our efforts to stop it, we cover the desert in solar panels to provide our energy instead of using atmosphere polluting fossil fuels. All the desert species that lived there are now killed off because their environment is completely shaded out by these solar panels, and they aren't adapted to living in shade, they're adapted to living in unrelenting sunlight. When the global temperatures continue to rise, and all the species adapted to more temperate climates inevitably die off, and the global climate becomes more and more desert-like, what have we done to all the desert-dwellers that would have thrived in that new climate? Have we really helped the planet in the long-run, or just seen to our own comfort in the present?
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I understand why it's your favourite presentation, it's quite funny. Take this for example:
