I think space colonization is an even bigger fantasy than relying on "future tech" that will magically terraform the earth and reverse climate change. We can have a tiny structure housing 10 or 20 people somewhere in our solar system for the price of millions of pounds of fuel and billions of dollars.

Inter-system travel will never happen. Forums like this tend to have a healthy population of the sci-fi minded, so it won't be a popular opinion here, but the laws of physics simply rule it out. And the "men once thought they couldn't fly" argument doesn't carry water with me. We know a lot more about what we don't know now than we did then