Dematerialization doesn't mean vanishing when hit by a "ray gun" (from the 1950's television space serials), it means using less to produce more.
This paragraph from a story in Saturday's Wall Street Journal should give you the idea:
If the cost of, say, computing power goes down, then the users of computing power acquire more of it for less—and thus attain a higher standard of living. One thing that makes such deflation possible is dematerialization, the reduction in the quantity of stuff needed to produce a product. An iPhone, for example, weighs 1/100th and costs 1/10th as much as an Osborne Executive computer did in 1982, but it has 150 times the processing speed and 100,000 times the memory.
One reason so many leaders of the global warming predict catastrophe is because they are Malthusians: That growing populations inevitably lead to starvation, shortages, etc. Yet, Malthusians have been wrong 100% of the time since the Malthus coined the term in the 18th Century. Remember how just a year ago we were running out of oil and now we learn that North America is practically swimming in it?
When human ingenuity is unleashed, we produce more with less and find new ways to do useful things. Even if word temperatures were rising (they are not), we can still count on innovative people to invent better tools (I'd rather have a car than a buggy whip) and new processes that will make life better. That is one of the many reasons not to sweat global warming even if world temperatures start modestly rising.