Rapidly and to not change the subject too much, I have to say I completely agree with you Geoff. There are many (physically possible) solutions to ecological disasters as well as ways to avoid another economic crisis, or to improve well-being (I mean after achieving it) in countries where people die of starvation or diseases everyday (to put some examples); but as you said, they are ideologically unwelcome, which makes them to be impossible... It is not a problem of viability but of power and will.
That said, and as we say in Spanish, "vamos por partes, como dijo Jack el destripador" (let's go step - part - by step - part, as Jack The Ripper said...). I think the sad clown and Chato made some important remarks that I'd like to comment (apart from thanking them). DCD and Geoff more personal reflections are very helpful in this "investigation" too.
I've observed, quite surprised I must add, that there are lots of people here who have been there, still are or, at least, think about it pretty often. It's interesting and enriching to know how you feel and why you feel that way, and gives, at least to me, another point of view from which to see the whole painting. But precisely because of this, we should be careful in our reflections. For in this field, there's a very thin line between life and death, as hard as that may sound. It seems more careful to me to take distance from the subject to reflect than get emotionally involved, which I know seems a little contradictory, yet possible. What I mean is to reflect about one as if it was another person, and take a cold attitude facing pain, anguish and horror. I know, this is easy to say and hard to do; but isn't this the best way to explore, instead of just feel? (it may not be, however I think it's safer, but are not more than suggestions).
I think it's better too not to use some tags. And I say so, on the one hand, because "optimist" and "pessimist" seem to be too ambiguous words to understand them properly, and on the other hand, because putting a tag to myself can provoke to believe I am something that maybe I'm not (and act theoretically in consecuence), while I am truly hidden under an ambiguous word. (I'm not very sure whether I explained myself here...). I used to say I was an optimistic person, I said this because I considered myself to be happy, maybe because I didn't feel like having the right to complain while others hardly survive. I haven't changed so much, but I know now I was kind of hiding to myself, that I had some personal conflict and contradiction that needed to be known (by me) and if not solved, at least thought. I think this can happen the other way too. If you believe you're a pessimist, you maintain a tendency to put your attention in the negative aspects of being, instead of seeing it all. (Note that, when a person is depressed tends not to see nor realize about the good aspects of her life - of course, to think about comitting suicide doesn't mean you're depressed).
I think you're right here, meaning is found in those interaction, but just there? I mean, can't an atheist lonely person, an hypothetical person that decides to live isolated from other for whatever reason give (or found) meaning to his life? Does his path inevitably lead him to comitt suicide? Or does the interaction with oneself count as intersubjective?
I would say that even theist people give to their life meaning of multiaxial character, though the answers to big theoretical questions such as "why are we here" or "what for" will probably always contain God in them, practically, I doubt that is God which gives that real meaning that work as a life motor. That's of course just my perception... But what I want to point out is that, due to the multiaxial character of meaning, it seems to me quite improbable that all the bonds break down together. However, I've suffered what you described, and although that didn't lead me to think about suicide, I can understand how hard it can be. Ok. Now I understand the problem with meaning. BUT, I insist that this is due to a difficulty to see the whole picture. Imagine you're a monk and, for whatever reason, you stop believing in God's existence, so that's not a bond anymore, and your life seems to end there since you have offered everything to God. I can understand the anxiety, the anguish, the horror. If fact, I think it's inevitable. But we are philosophers (we like to think, reflect, discuss, so we are, and there's no discussion here.. lol xD), we have to be able to value the world that opens for our eyes. Heidegger said that man is a possibility being and, that the only possibility that he cannot avoid is death. So there you can find new meaning(s), exploring those possibilities, choosing, living. Maybe in this emptiness you're when rejecting God the easiest way to go is hedonism: just find pleasure. You will inevitably create binds with time and contact with the world, you'll have to work so you'll meet new people, and based on an hedonist attitude you can enjoy social activities where meet more new people. I think you could enjoy even your solitude, reading, listening to music, writing, masturbating... whatever! But maybe for a monk, there's been enough solitude for the moment
You'll be given the opportunity to live just once (at least if you believe that there's nothing after dying). It's just casualty, but... isn't it amazing? Think everything you can do just because you are alive! The big difference between life and death is possibility. Life is the scenario and death is the only possibility that kills any other. If you take any choice in life, you can always change no matter how hard this could be; if you decide to end your life, that's it, there's no possibility left, it's over. And think that, you are going to die anyway, so why rush? Life's not so long as it seems to be, so, I think it's better to understand life as an scenario where you can act by trial and error, and where you can enjoy millions of trivial things and activities, rather than understand it like a torture, or horror. This anxiety is just a possibility too, and it could always be there, but it doesn't need to be the only present thing in ones life.