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I don't think people really grasp the majestic scale of evolution. All living things are constantly evolving, all the time, in response to threats. The Earth has seen rising temperatures before, but what it didn't have back then was grass.

The dinosaurs evolved to get big because they couldn't graze. After the meteor got rid of them, grasses started to overtake the land, providing food chains for herbivores that simply didn't exist, and megafauna went from reptilian to mammalian.

Mammals are more adaptable than reptiles ever were, and the other great offshoot of reptiles, birds, are more adaptable still. The hit to biodiversity that climate change creates may not be as large and cataclysmic as we think it will be.

And it may be very short-lived. We can geo-engineer as a stop-gap until the rest of the world catches up technologically. China's already starting to successfully push back, Latin America and Africa really aren't that far behind. The developed world already slowed its contribution to climate change massively and is getting better all the time.

What I worry about is that we won't be able to save large cetaceans. Dolphins seem to be doing fine, but the larger sea critters are barely hanging on. But my thinking is that the biggest hit to their ecosystem happened 50 years ago and it didn't kill them, so they're adapting to noisier oceans. Maybe they're not as fragile as we think.

Ocean acidification has destroyed much of the diversity of coral reef ecosystems, but I don't think we'll ever reach the point where jellyfish take over the seas again. We're seeing blooms but mammals can figure out how to eat them.

Managed climate change can have the interesting effect of making the world's ecosystems more and not less robust.




Adaptability depends on having enough generations to adapt. Animals on one-year breeding cycles are a lot better off, while cetaceans are long-lived and the change happens within their lifetimes.

> The hit to biodiversity that climate change creates may not be as large and cataclysmic as we think it will be.

It may be hard to separate from other human-induced loss of ecosystems and biodiversity, which is happening at a high rate.


> Adaptability depends on having enough generations to adapt.

Just going to be a pedantic nerd and add that population size is the other major factor in adaptability. Larger populations generate more variation per generation.


The two are very closely tied together and depend on the precise nature of the environmental change. The slower a species breeds, the less likely it is to have recovered enough variation for their population density to survive successive changes. The industrial revolution saw unprecedented changes in air, water, and biomes only to be followed by the mass human expansion of the 20th century which further strained ecosystems simply due to the sheer scale of it.

I fear the majority of species will not be able to survive the third event.


And where do you get the idea that animals lacking adaptability will survive under any circumstances ?


Can you elaborate on 1) when the last time the earth saw temperatures like what are forecasted in the next 100 years (4-6 deg. celsius increase without large scale changes in energy consumption) 2) how much evidence exists that grasses because widespread above the k-t boundary 3) evidence that dinosaurs evolve to large sizes because they couldn't graze 4) evidence that there were not herbivorous large dinosaurs 5) evidence that ocean acidification is the cause of coral reef die-offs/bleaching 6) when jellyfish previous were an apex organism in the ocean ("take over the seas again")?


Speaking to 5)

"Warming causes coral bleaching (Figure 1C), which is the breakdown in the symbiosis between corals and their symbiotic dinoflagellates (zooxanthellae), which are essential for coral growth. Acidification decreases calcification and may ultimately result in the inability of corals to form a skeleton." [1]

"Although higher pCO2 conditions do not appear to have a strong negative impact on physiological parameters, ocean acidification will have a negative impact on both colony and coral reef ecosystem scales. The reduction in calcification for these coral species will lead to generally weaker skeletons, increasing the risk of physical damage and bioerosion at the colony level" [2]

[1] http://journals.plos.org/plosbiology/article?id=10.1371/jour...

[2]https://s3.amazonaws.com/academia.edu.documents/46650429/Phy...


Re 4: I don't think the claim was that there were not herbivorous large dinosaurs. I think the claim was that the herbivorous large dinosaurs were not grass-eaters.


Taken together, I hope it's clear that I'm not certain that evidence shows that grass co-evolved with radiative mammalian evolution post k-t. I could be wrong, but I'd like to have some references so I can be correct in the future, if that's the case.

Are current and pre-holocene megafauna grass specific or generalist herbivores?


Re #1: About 125,000 years ago[0] during the Pleistocene epoch. Wikipedia has a history of Earth's temperatures[1].

Somewhat related, XKCD[2] made a nice illustration to explain the temperature fluctuations of the last 22,000 years.

[0]: http://science.sciencemag.org/content/355/6322/276

[1]: https://en.wikipedia.org/wiki/Geologic_temperature_record#/m...

[2]: https://xkcd.com/1732/


An aside, but simply because we are talking about birds; Given how many birds there are in the world, I have always been amazed at how few dead birds I have seen in my life.

I've always been amazed by birds in general, but this specific thing, for whatever reason, has always been interesting to me.


> I have always been amazed at how few dead birds I have seen in my life.

Dead pigeons are a regular sight near urban tram centers, sometimes even inside subway systems. Breeding season is especially bad, not a single year where I don't see some "fallen out of the nest" eggs with half-developed dead birds.

In more rural areas the corpses tend not to stick out as much in the underbrush, you might be walking past all kinds of dead wild birds without even realizing it.


They keep flying and dying crashing into my windows, despite a dozen eagle silhouettes being glued to them. What else can we do?




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