Hal9000:
Everything that causes heat contributes to Global Warming. However, a single volcanic eruption does more than the entire past 100 years. The total number of rocket launches since the 1940s is only a drop of water in the ocean in comparison. Sure, each drop contributes. But we have a long way to go to reach the trillions of drops necessary to make a difference.

Deadly Ernest:
You are wrong. The thing stopping private companies from developing their own spacecraft or programs is the cost of complying with government regulations. The EPA waivers alone for air pollution, launch site alteration and hazardous waste would bankrupt most companies. Then add the FAA, DHS, FBI clearances; it adds up quick.

Silent Running:
Self destruct just makes a whole lot of little peices. Turning a single cannon ball into a shotgun cloud and increasing the chances of a hit. What you want is launch vehicles and satellites that don't shed pieces during launch or operation. And have the ability to do a controlled deorbit to drop them into the ocean or burn up for disposal. Better yet, is to drop them in a location you can pick up the peices, or recover it.

All that junk will eventually "clear itself" from our skys by solar wind, atmospheric drag, or gravitational imbalances accelerating them to escape velocity or deaccelerating them to deorbit. The problem is that doesn't happen fast enough to make much difference to us.