Is there any urgency to creating a self-sustaining off-Earth presence

In 1962 I was 14, and I remember the Cuban Missile Crisis as if it were yesterday; that night, waiting for the bomb, my brother and I lost our innocence; Mom and Dad could not protect us from everything;

Leap forward to Y2K, and “the end of the world”, it was less frightening to me, as I knew from IT people that I worked with that it would not happen to the extent that was predicted; if at all; but others didn’t have access to that knowledge, and I was on suicide call that night; no one I know, died that night; but the terror was real;

As a species we have only crawled up out of our caves and huts, given up our hunter gatherer ways, to embrace “civilization” and “farming” 9,000 years ago, just after the end of the last Ice Age; we are in an intermediate phase; and have just about used up the easily available resources on this planet; if it were not for our advance technological society, the resources that we need to exist, would be beyond our reach and we would have drifted back into the Stone Age, hundreds of years ago;

Regardless of what ‘Might’ happen in the way of a catastrophic event, we are coming to the limits of Earth’s ability to sustain our species; “The Bank Account” that we have been drawing on, is coming close to being empty, unless we find a fundamentally new source of energy, new resources and ways to feed and cloth the 9 Billion people that will inhabit this planet in 39 years;

Climate change is real, and has always been around; it happened 10,000 years ago with the last Ice Age and has been fluctuating ever since; regardless of who is to blame, it is happening now; and we are able to monitor it for the first time; Social and Cultural Upheaval is inevitable, and will be uncontrollable if we don’t have alternatives in place before the middle of this century; while there are many people working on those alternatives here on the planet, and a few far sighted ones working on Space alternatives, we need a “Manhatten” style project to kick start real change; bits and pieces randomly scattered about, competing against each other may leave us no time;

How urgent is it; Extremely Urgent; the Tsunami of 2004 and the earth quakes on the Pacific Rim last year are a small taste of what can happen; they didn’t matter when the human population of this planet was only a few million; but now that we are concentrated in some of the deadliest volcanic areas on this planet, the threat is huge; we have seen how Minor Volcanic Events, such as in Iceland, can affect whole regions, and how Solar Flares can knock out our Electrical Grid as it did in Canada's province of Quebec; do we really need a Tunguska or Meteor Crater Event to prove that we are an endangered and vulnerable species; 

Believe it or not, since the middle of the 20^th Century, humanity has experience the most profoundly peaceful times in the last 2000 years; the danger of dieing from wars has decreased with every decade, regardless of what some politicians and generals will tell you; the amount of co-operation amongst developed and developing nations has been phenomenal; for those, and for all the reasons I have given above, now is the time to push forward to become a Space Faring Species; I don’t say multi-planetary, as I feel that is too limiting; in some ways, it would be easier to build Space Stations, rather than try to live on inhospitable planets; but I don’t think we should ignore either;

To answer the last question, how long do we have to build a half-sustaining off world presence? I am not sure a half-sustaining presence would survive; it most certainly would be a finger nail clinging to the rock face of the cliff existence; much like the bottle neck that some think existed in South Africa when the rest of Africa became a desert and uninhabitable for thousands of years; not that that was the only time; it is only the most profound;

I would prefer a fully self sustainable presence, based on Space Resource Utilization, not dependent on Earth; whether it is 100 on an outpost or 10,000 persons scattered in groups through the solar system; so long as they were able to be Space Faring, and had a sustainable economic infrastructure, that is all that would matter; 

Starting now, with something between what we have now and a full blown “Manhatten” project, we could be out there in a generation, (80 years) living, breeding, settling and exploring the Solar System out to the Oort Cloud, with the rest of Space Beckoning;