It's difficult to find aspects of the 'climate change debate' to discuss in articles like this one. The scientifically substantive debates require a lot of effort to properly engage -- one needs to penetrate a whole scientific subdiscipline, complete with its expert lingo and well-worn (or theoretically justified) assumptions. And maybe the science is not always worth examining from the sidelines. The social and political aspects of the debate are sometimes, somewhat paradoxically, more temporally relevant than the scientific ones. For example, the politics of atomic weapons -- how and why we menace each other with nukes -- have more to do with humanity's survival than the science of nuclear chain reactions. The politics of environment -- how and why we justify risking our life support system, Earth -- also have more to do with our well-being than the sciences of geology, climatology, or ecology.
I've previously said that humanity has no viable alternative to Earth. Until I see a successful Biosphere-like experiment (building a sealed box and living in it, with only energy as input) I have no reason to doubt this. We simply do not know how to survive, long term, without Earth. Not even through entirely synthetic means -- not even if we were willing to survive indefinitely on some manufactured nutrient-sludge.
If you don't believe me, look at this page describing the nutrient cycling on the International Space Station. Below is a from that page. See the labels, 'overboard venting'? That's matter being lost to space that will need to be replaced eventually. Also, many of the processes depicted require ingredients and generate wastes that are not explicitly depicted. I don't think any space mission has generated its own food, for example. We don't know how to plant people inside bottle gardens.
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