The page lists supposedly rational reasons for wanting to do this but I think it's really just a romantic idea with no rational justification.
Introducing new species into ecosystems is always risky, whether or not they're extinct. No one knows what would happen if we start "resurrecting megafauna". No one can say if reintroducing Mammoths will have a positive, negative, or no affect at all on climate change. The idea that scientists can answer questions like that is wrong.
I'm all for conservation but this isn't that. This is "because it's there".
It's the precautionary principle that's irrational. The status quo isn't inherently desirable. It's not true that "know one knows what would happen." We don't know everything that would happen, but we do know a lot. We also know what is happening now, with an important ecological niche unfilled.
Humans have historically had enormous effects on the planet, in all sorts of dimensions. At this point there's no avoiding it, but we can be more thoughtful and deliberate in how we manage our environment.
Well, I mean, going to the moon was another "because it's there." I don't see anything wrong with trying to do incredible things just because they're incredible. We learn a lot along the way.
personally I think we should be placing any prehistoric megafauna into some kind of fenced-off island zoo, where they can be monitored by scientists and visited by tourists. I can't see anything going wrong with that approach.
Megafauna are going to have low birth rates and be easy to track and cull. So the risk seems fairly low compared to say insects or seeds or bacteria that can never be reigned in once they are out in the world.
I wonder if, even without finding human cities or remains, you could infer our existence from the fossil record, from the layer where a boatload of plant and animal species went from being localized for millions of years to being all over the place all at once.
There's good evidence for asteroid impact(s) at that time period, and hugely dramatic climate change - swings of over 20 C in the average temperature in the north.
They're giant slow breeding herbivores - if they're present a problem we'll have no more problem wiping them out than we are with the elephants.
The primary concern should be the welfare of the beasts - they're ice-age animals, and are fundamentally incompatible with the climate as it is, let-alone the sweltering wasteland/dessert/tropics that we're turning the world into.
Introducing new species into ecosystems is always risky, whether or not they're extinct. No one knows what would happen if we start "resurrecting megafauna". No one can say if reintroducing Mammoths will have a positive, negative, or no affect at all on climate change. The idea that scientists can answer questions like that is wrong.
I'm all for conservation but this isn't that. This is "because it's there".