My thoughts? We have what -- roughly 100 years or so of reliable, reasonably complete, fairly accurate records of climate and temperature? In addition, we have general evidence across a variety of scientific disciplines that suggests that large-scale climate change happened long before humans appeared on the scene and continued long after. Sometimes, the world is in a warming trend in which vast oceans and seas cover the land. Other times, it is in a cooling trend in which the terrain is covered and marked by glaciers. These trends last for centuries (or longer) and are thought to have prompted or encouraged great evolutionary change as species either adapted to change or died out. That being the case, I'm not so sure that our puny records of single-digit average temperature changes over a decade or two are really much to go by. Honestly, any averages with which we come up amount to tiny little drops in the proverbial bucket. We just haven't had adequate measuring devices and/or standards of measurement and/or easily accessible records for all that long.
Also, I think it's a lot of hype. The climate changes. We know that. That's part of how we get lush forests and barren deserts that were once seas. That's how we get canyons and valleys and whatnot. Over time, species either change right along with the landscape or die out. That's what science tells us, anyway. I distrust science that, based on current and/or contemporary warming and cooling trends, paints doomsday scenarios over relatively short periods of time. Maybe I've just got my head stuck in the sand, but I find it incredibly difficult to believe that the relative evolutionary eyeblink that is the industrial period of human history is likely to cause widespread, irreversible climate change with the potential to devastate entire populations of Earth's flora and fauna (including that of humanity). I think it is much more likely that we are witnessing the beginning of a perfectly natural climate change that only feels like "change" to us because we don't have recorded temperatures for the last time this happened.
Finally, even if recent human activity has contributed to climate change that may facilitate a mass extinction and drastically change the types of species present on Earth, I have a hard time finding that to be inherently unnatural. Species do what they do. Sometimes, too many of one type of species changes the food chain and wipes out many other species by both direct and indirect means. That's perfectly natural. If our species creates climate-altering waste and proliferates at a rate that has a negative impact on the populations of other species, then so be it. That's just mother nature at work. Our job is to figure out how to make sure we adapt with the changing world so that we don't die out, not to figure out how to keep the world looking as close as possible to how it would look if humans, with their natural tendency to adapt by altering their immediate environments, had never walked it. Why would we even want to do that? Why does everyone just assume that the effect that humans have on the environment is bad and/or unnatural? Maybe we're doing exactly what we were supposed to do. Just as the dinosaurs before us paved the way for mammals, maybe we're paving the way for some other form of life.
