A couple of points.

>So the rising and warming oceans are going to drown the great coral reef ecosystems? No problem -- every coral reef in the world was drowned by the great meltwater pulses at the end of the last Ice Age. They reconstituted themselves after a few thousand years. They can do that again.

NOAA says it takes 10k years at least [0], which is quite a long time, and that's assuming optimal conditions. Reefs are immediately threatened by ocean acidification, warming waters, biodiversity loss, and physical ecosystem destruction. In current conditions, all coral reefs will be in danger of extinction by 2050; 10% of world coral reefs have already died off. (and the damage due to bleaching and biodiversity loss at those which haven't yet is obvious and apparent to every person who has frequented them in the last 30 years)

I don't think anyone is particularly worried about humans ending the long time viability of life on Earth; we can't wipe out everything, and the Earth's ecosystems will recover over a period of time proportional to the size of the human caused disaster. It's sort of alarming that you present such a straw man argument, as if you're reading a science fiction novel, where it's all going to be okay because in a few million years, things will be back on track again, and you seem to be completely unconcerned with the immediate impacts and benefits of these ecosystems, completely detached from the reality at hand.

We're talking about real ecosystems and their incalculable impact (there are estimates of the economic importance of reefs, but it is the scientific and social impacts which are incalculable) on real people, alive today, living right now, that should be alarming and upsetting enough without considering long-term geological scale issues.

A second point.

>Fact is, a lot of the rest of the chaos that is predicted from climate change is, on a long baseline, a more or less normal state of affairs.

This statement is actually most inaccurate when it comes to the current rate of climate change. There are multiple studies, and levels of evidence, at multiple geological time scales, which show that the current and predicted rates of warming are unprecedented throughout geological time. The current rate of warming is faster now than at any time in the last 11,000 years [1], and it may occur faster than any climate change which has occurred in the last 65 million years [2], current rates of warming are substantially faster than that at the end of an ice age [3], and CO2 levels are currently higher than at any point within the last 800,000 years [4].

It is important to understand that these issues will have real impacts on real people in the immediate future, and being optimistic on the scale of geological time is absurdly detached from a day to day reality.

Climate change, biodiversity loss, and ocean acidification will have serious impact on the immediate time scale, and are largely unprecedented in the geological time scale.

[0] http://oceanservice.noaa.gov/education/kits/corals/coral04_r...

[1] http://www.slate.com/blogs/bad_astronomy/2013/03/13/global_w...

[2] http://news.stanford.edu/news/2013/august/climate-change-spe...

[3] http://oceanservice.noaa.gov/education/pd/climate/factsheets...

[4] http://thinkprogress.org/climate/2014/04/09/3424704/carbon-d...