@Thinkaholic, I mentioned modern behavioral psychology in my previous comment. One example of this is
Acceptance and Commitment Therapy, or ACT, which is a worldwide evidence-based effort; it had a brief moment of fame when TIME magazine interviewed its founder, Steven Hayes. Another interview with Hayes is
here.
A couple of points from ACT and other schools of psychological thought seem relevant to any fears we might have about the possible extinction of humankind & what we can do about it:
1) Animals can't suffer in pondering possible futures because they don't have a powerful symbolic language; humans do, and so we
can imagine such futures. But it's worth noting that the future never exists as such; only the present. So one way not to get sucked into worrying about things we're not sure will happen is by paying attention to the present moment. The present is where we live, moment by moment; it's where we can take action based on what we care about.
2) Humans can and do make meaningful lives despite all sorts of dire situations. Another psychologist,
Viktor Frankl, became famous for inventing a school of psychology out of a personal experience of discovering deep meaning and purpose to his life while he was imprisoned at a Nazi prison camp in German-occupied Czechoslovakia during WWII. He called his psychotherapy "Logotherapy"; it is not much practiced today, but was very influential on later research by others. A quote from the
Wikipedia article on Logotherapy: "Rather than power or pleasure, logotherapy is founded upon the belief that it is the striving to find a meaning in one's life that is the primary, most powerful motivating and driving force in humans."
Frankl wrote about one of the key incidents that changed his life in the camp in his book,
Man's Search for Meaning. Escape attempts from the camp were common, but only sometimes successful; even so, life at the camp was so invariably fatal over time that usually anyone who had a chance to join in an attempted escape would do so. Frankl had been offered such a chance and had decided initially to accept. He describes what happened next; just a quick note that he was also a physician, and in that role had volunteered his services to his fellow prisoners:
"I made a quick last round of my patients [just before I intended to escape], who were lying huddled on the rotten planks of wood on either side of the huts. I came to my only countryman, who was almost dying, and whose life it had been my ambition to save in spite of his condition. I had to keep my intention to escape to myself, but my comrade seemed to guess that something was wrong (perhaps I showed a little nervousness). In a tired voice he asked me, 'You, too, are getting out?' I denied it, but I found it difficult to avoid his sad look. After my round I returned to him. Again a hopeless look greeted me and somehow I felt it to be an accusation. The unpleasant feeling that had gripped me as soon as I had told my friend I would escape with him became more intense.Suddenly I decided to take fate into my own hands for once. I ran out of the hut and told my friend that I could not go with him. As soon as I had told him with finality that I had made up my mind to stay with my patients, the unhappy feeling left me. I did not know what the following days would bring, but I had gained an inward peace that I had never experienced before. I returned to the hut, sat down on the boards at my countryman's feet and tried to comfort him; then I chatted with the others, trying to quiet them in their delirium."
So - back to your question. Suffering is normal for humans - sickness, old age, death, etc. Many societies throughout human history have endured troubled times or been destroyed; and as jackwhirl has mentioned, even the universe may come to an end - although there again we are talking about a "future" that exists solely as a symbolic construction made possible by language. We live
now - we need not be prisoners of a symbolic construct. So regardless of the scenario, whether distant or immediate, whether speculative or seemingly quite real, we can choose what we value about being alive & thus how we respond.