Wait a minute. Or a day, or a year, or a millennium. What are we doing here? Nature has worked for free for millions of years until the Industrial Revolution began to carbonize the environment, and the beginning of the century in 1900 ushered in the chemical pollution and waste that became pervasive in the subsequent World Wars and the conflicts after that. What drives all this destruction? Growth for profit.
Growth of civilization is not a force of nature, it's a characteristic of unrestrained population expansion due to the human intervention in natural cycles. Not to say that's completely out of line, but we've overrun the ecosystem with our lack of comprehension on how we should "fit" into our niche. Basically it violates the UN-adopted concept of sustainability.
This runaway growth of one species has mushroomed into a massive impact that must pull back significantly, with a restoration of natural processes in an intelligent fashion. Yet we now have a form of denial in the concept of re-engineering the earth, when we can't even keep our own systems going without massive costs or energy transfers. These untested and massive-scaled interventions address only one dimension of any given problem, when we really need to understand that we've unbalanced the system, which has to return to its "resting" state. These interventions are like any other "bubble" that we've produced financially, for example - they collapse. Some ways of returning to the balance are better than others, but they've all got to start with scaling back our use of the planet for single-purpose efforts. The BBC article on the feasibility of geoengineering the earth states this in its preface.
Sustainable development has possibilities, but hacking the earth is pure dystopian panic, and as Prison Planet points out, the US Government is already doing this on a dangerous and untested scale.
So chill out, everybody. A steady, focused multi-systems reversal of ecological damage is key to this problem that has been over 300 years in the making by human civilization. A forward push in new technologies in Net Zero design of reconstructed cities is another viable strategy, as is urban reforestation and ecological repair. All of which we would not be paying for now if we had forestalled the growth of human populations and its consumption much earlier. So we need to figure out how to get commerce and the corporations to pay back for all this. The clawback, as it were...