and nuclear power - appear not to be up to the challenge. But not everyone's demoralized. MARTY HOFFERT: Try to imagine what the world was like in 1899 compared to today and what the technologies were that were being envisioned by even scientists and engineers and what actually happened. They missed the movies. They missed airplanes. They missed automobiles. They certainly missed space travel with nuclear power and radar and lasers. And so there's really an issue of sort of timidity in the way that we've been projecting the technologies that might mitigate the fossil fuel greenhouse effect. NARRATOR: Hoffert argues that many of today's energy technologies - like nuclear and solar - came out of government-funded military and space research. So perhaps we need a Manhattan Project to find the technologies to combat global warming, technologies which might capture the sun's energy in space and beam it to Earth, technologies like nuclear fusion, offering limitless carbon-free energy, even technologies which extract the carbon from burning fossil fuels and sequester it back into the ground, and other technologies which today are simply unimaginable. [www.pbs.org: Technologies "beyond fossil fuels"] MARTY HOFFERT: But we haven't been doing any serious research on this problem. When I say "this problem," on the problem of how do we power the world on a long-term basis with carbon-free energy? NARRATOR: If the technological obstacles to combatting greenhouse gases seem difficult, the political challenges might be even greater. Even before the Kyoto conference started, the idea of