"Manned Interstellar fight is where you are very much off. "
Most likely we should probably be concentrating on interplanetary expeditions now, but interstellar trips may not be as far in the future as you think. It is true that we currently do not have the technological wherewithal right now for Star Trek type space flight, but a generation ship is not out of the question. In 1998, NASA launched Deep Space 1. This runs on an ion drive rocket engine generating 1/50th of a pound of thrust. Not much compared to traditional chemical rockets, but it is capable of constant thrust for a very long time. Given sufficient fuel, such an engine is capable of eventually reaching an appreciable fraction of light speed. Here is a link to an article discussing ion drive propulsion and the Deep Space 1 mission: http://science.nasa.gov/scienc...
It may be that you can't fix everything, but we have to start somewhere, and doing something is better than doing nothing.
I disagree with this, partly because I don't subscribe to the alarmist notion that global warming is going to cause global life threatening catastrophe and largely because anything we do to try to reverse global warming stands a good chance of backfiring. A couple years ago an experiment was done in the Arctic involving reflectors to preserve the ice cap. The experiment was successful in that it brought down the local temperature in the immediate area. The problem is that this kind of solution has the potential to set up a positive feedback loop that could cycle out of control. In an effort to reverse global warming, we might cause more damage with too much cooling, which would be worse than the warming. I do not accept at all that the warming caused by human activity is going cause Earth to become a hothouse for reasons I have stated elsewhere (http://slashdot.org/comments.pl?sid=5024323&cid=46741263). In this instance, it seems likely that doing little or nothing may be the best possible solution.
Mediocrity finds safety in standardization. -- Frederick Crane