We increased CO2 concentration by about 200 parts-per-million (a factor of about 2x), and increased the average temperature by about 1-2°C. Rain patterns are slightly different. Ocean PH levels dropped by about 0.04 .

Sure, given how delicate the biosphere is, these small changes have a significant effect. However, if we look at Earth on the same scale as any other object in the solar system, the environment on Earth today is almost identical to the environment on Earth 1,000 years ago. The atmosphere is about 1023 millibars; 78% nitrogen, 21% oxygen, 1% argon, and 0.04% everything else. Liquid water covers most of the surface, with an active water cycle causing water rain to occur periodically over much of the planet.

The temperature change is so small, that we would not notice it if it were on any other planet in the solar system, and it is far below the noise floor of day-to-day variance

And don't forget that the Earth is more than willing to enter a negative feedback loop -- she will take that 1-2 degree increase in temperature and say "I heard you like warm weather, so I'm gonna release all this trapped methane and CO2 from my frozen parts and let you have it too."

I interpret this as you misinterpreting the opinions here, confusing them with the opinion of unrelated colonization-fanatics, via an unknown mechanism; I will not attempt any defense of either perspective right now.

Attempts to terraform Mars allow humans to try some things and to see what happens. It will allow to make our models of climate more precise.

For now our understanding of a climate based on observational studies. Not a controlled experiment. So when we start to do something having some climatic goals in mind, we'll start to learn a lot. And it would be better for Earth if we started with Mars.

Though we have no time, but it doesn't seem a sufficient reason not to try get at least some experience from terraforming Mars. It may reduce risks.

I don't agree with the logic that we cannot focus on two things at the same time. It's like saying, "People focusing on making movies when we have such an immediate problem to address TODAY are delusional and actively endangering the most vulnerable people in the world." or "People focusing on curing fibromyalgia when we have such an immediate problem to address TODAY are delusional and actively endangering the most vulnerable people in the world."

The bottleneck to reversing climate change is not money or manpower, it is politics. We cannot force other people (especially in other countries) to do the right thing for the environment. We can, however, do our best to improve things on our side and pressure others to do so as well. And while we are putting our best effort towards that, we shouldn't stop making art, researching medicine, or even, trying to colonize mars.

Also, the research and development needed to colonize Mars may very well yield scientific discoveries that allow us to reverse climate change. And even if it doesn't, and Earth is ruined despite our best efforts here, we won't have all our eggs in one basket.

My point is, I just do not believe that researching colonization of Mars will do anything to thwart our efforts to improve the Earth. Quite the contrary, it may help those efforts.

This times a million. I see it all the time on social media when it comes to news stories too, and it's as ridiculous there as it is here. People have different interests and skillsets, and they don't all need to focus on the same thing at the same time. The folks looking to explore Mars colonisation/space exploration and those working to slow down or prevent climate change are usually entirely different groups, who have studied what they're interested in for years. You can't just chuck them all at a single 'project' and refuse to allow anything else, in the same way we can't pause the rest of human civilisation because your pet issue isn't being sorted quickly enough, or have the entirety of a media organisation reassigned to a single story.

We live in an environment that's we're so conveniently adapted for us that it's easy to take for granted. You can spend your whole life doing damage to this precious thing we all got for free and die before the consequences of your actions catch up with you. It's all too easy to just miss ecological thinking altogether.

On a spacecraft though, or a Martian colony, the f-around-find-out cycle is gonna be deadly short. You're gonna need everyone in board with doing what they need to to stay alive.

Again, something we desperately need on Earth.

So let them fail to colonize Mars. Let them fail 100 times. Because what we learn from those failures just might save us at home.

https://www.fao.org/sustainability/news/detail/en/c/1274219/

It's many orders of magnitude easier to afford a $100,000,000 home if you make $10,000 per year than if you only make $1 per year.

But you're never going to afford that home either way.

I had never heard that. More info https://en.wikipedia.org/wiki/Chicago_River

On what are you basing this statement? I would argue that entirely depends on the complexity of the species and the time per generation. Bacteria certainly can adapt to extremely different conditions within years, if not even quicker. And these "simple life forms" are arguably much more important for the ecosystem than more complex ones like mammals.

When it comes to changing climate (and some degree of pollution) instead of newly evolved adaptations you get migrations or selection for particular alleles. Adjust up and back down and you can end up with diversity constraints on both ends.