>we might not successfully craft off-planet ecosystems that will sustain us indefinitely.

Not on the first go. So we should start early.

I think that learning how to craft off-planet ecosystems is a large part of what is going to help us stem damage down here. Where would solar power be now without the early adopters in the space industry?

"I think it's that if we can't avoid damage to multi-billion year evolved, robust ecosystems on our home planet, we might not successfully craft off-planet ecosystems that will sustain us indefinitely."

And so...?

Even if true, that doesn't lead anywhere. If you're trying to faintly imply we shouldn't try, you ought to bring the arguments up to the surface, where examination will quite likely show they don't have that much substance.

Just because the natural system has tolerated meddling and abuse does not amount to crafting. In fact the exercises of trying to create an artificial system failed miserably... and will likely again. And that's a great reason to try to go to space, to learn about how incompetent we are with our tech despite being full of ourselves by taking all the things provided freely by the earth for us to abuse and exploit while giving back virtually nothing. I mean humans often don't bury their dead naturally they burn them or embalm them... we give back nothing, we take everything: THIS IS SPARTA!

The “natural system” has tolerated millennia of “meddling and abuse”, and that “meddling and abuse” has largely served to make the ecosystem more habitable to humanity. We don’t even know what an un-“meddled” nature would even be like. Even the Amazon rainforest is in large part a product of human cultivation starting 11,000 years ago. The transformation of aurochs from a wild megafauna to a technology to transform inedible grass into edible milk and beef is also over 10,000 years old. The artificial evolution of our hunting and working companion, the dog, is millennia older still.

It's telling a millennia is 1,000 years. 10,000 years is a blink of an eye. The dinosaurs were around for over 160 million years, that is sixteen thousand times longer -- talk about a millennia. More habitable for humanity, deadly for pretty much every other living thing. Heck we were even doing all that much until 300 year ago -- that's 160 million divided by 533,333. So let's see the damage we did in 300 years multiplied by 533,333 times, yeah we're going the way of the dinosaurs almost half a million times faster than the dinosaurs.

We need maybe like 100 million or less people total on the planet. And 7 or 70 or heck 700 billion littered through the rest of the solar system. The chances of the survival of our species and life in general on the planet the would be infinitely greater than what we have done in the past 300 years. Population growth outside the planet raises absolutely no questions about the survival of the planet or species. The rest of the solar system is already completely and utterly dead as far as we know. No arguments about pollution or stability or sustainability or survival apply to it.

The rest of the universe as far as we know is our canvas, but please spare the damn planet from where we came. It's rare and nearly impossible to replace.

"tolerated" nothing like we've thrown at it in exponentially increasing form every year since 1900... and by all accounts it's not "tolerating" it very well at the moment. Fisheries? Sea water contamination? Air pollution? Groundwater contamination (fracking? agricultural runoff?) Rainforest loss (The Amazon! how many hectares lost per day? Palm oil plantations supplanting Indonesian rainforest, etc...) all on top of human caused climate change...

1) We have been around less than 1 million years. Our industrial revolution began less than 300 years ago. We constitute 0.01% of earths biomass, yet have destroyed 83% of wild mammalian life https://www.pnas.org/content/115/25/6506 We have polluted the oceans to the extent that plastic bags and radioactive fallout from WW2 can be found in the bottom of the Marianas trench. We are in a mad rush to burn the accumulated carbon reserves from millions of years inside of a span of decades. We are currently on a trajector to turn this planet into a place inhospitable to most life forms, including ourselves. https://xkcd.com/1732/ Last year was the highest carbon-output year on record, just as the year before was, and the year before that one.

We are utterly destroying the only known home to life forms in the universe. We are doing it rapidly.

You seem to be living in a delusional parallel reality in which establishing a space society doesn't consume the resources of our ONLY current home planet and doesn't pollute it.

We must change our ideologies, our thought patterns, our cultures, and our entire industrial societies patterns and habits (not to mention energy source) within the next decades to survive, let alone thrive or develop further.

I don't get the sense that you comprehend our actual condition on this planet. There is a very very steep footprint curve with regards to both our population (There was roughly 1.5 billion of us the last time we all tried to kill each other, World War 2. Now there are 7 billion of us. Before, the consumption footprint of a person was rather low, now each person consumes more resources than ever before, and this amount of consumption continues to rise. The Chinese middle class will surely want every accessory their American counterparts have, right?)

How has this entire predicament avoided your scrutiny until now?

I'm not denying that problems exist. But I'm also not going to resort to pessimistic doomsaying about them, either. Most of the problems you mention are already being solved.

If anyone's living in a delusional parallel reality, it's you and your apocalyptic rantings.

Actually talking about the Amazon as a great feat of human stewardship is perfect. Humans are capable of making nature better, but I sense one major caveat: when you name the Amazon as a human endeavor you forget that all the species that make the Amazon such a biodiverse place were already there. Humans might have made the Amazon a better place, but alle the ingrediënts were already there. The timescale of humans transforming earth is mindbogglingly short in terms of the timescale of "nature". Nowadays we are destroying species by the millions (not millions of individuals of a species, but millions of species!) This destroys the possibility to create a better system because the capital for creating one is destroyed.