We will never move to Mars, living to a 28 rather than 24 hour cycle has been proven to descend us into madness. It seems we are stuck with the planet we have got. Even if we invented the starship enterprise, the second we beam onto an alien planet with any form of equivalent life its instant death from entirely unfamiliar viral and bacterial strains.CPRE would like us to build on all brownfield sites, in preference to the greenbelt, but won't acknowledge how badly contaminated many of them are. There is a figure for the heavy metals that is the limit for home construction. So many parts per million of toxin Y and you can't build there. I know the number for lead and I know that it is simply ignored or bypassed. If it were strictly followed there would no new build homes in most English cities. Full stop.
Browns Foundry Yard is irregularly polluted by the mineral salts that are added to the molten iron mix, such as Manganese, Vanadium and Chromium. This is entirely hearsay and I should need to watch the sampling taking place to have trust in any purported figures. The unusual pioneer vegetation on this site indicates disturbed soil chemistry - the ground is certainly quite acidic and nutrient poor.
Below about 1g/kg soil dry matter lead acts as a fertiliser. (Technically a soil conditioner - the plants 'read' it as calcium). This is why the Ouseburn looks so glorious in June. Above a certain level of soil lead then seed germination is slowed or stopped and it is very noticeable that at Calders Yard the ground is still bare ten years after the buildings were cleared. Without the dreadful contamination it should now be thriving pioneer woodland (like Browns). Perhaps the greatest risk will be to the groundworkers on the site and to the builders as when the people move into the flats, or whatever, the bare contaminated ground will mostly be covered over and so made safe. There will be talk of 'remediation' but, short of paring the ground back to boulder clay what can they do? (BS, is what they *will* do).
Sadly, Global Warming appears to be runaway - exponential - and it certainly appears this way in the Arctic. The endpoint of that is Mars and there's a correct term for the process (it's not Marsification). It's quite disturbing already and I dread to think what will happen when this view is accepted widely.
I reject your nihilist view. We have to keep trying.