France is now rushing to construct the International Thermonuclear Experimental Reactor, (ITER), which is supposed to show that nuclear fusion can be used to power nuclear power stations. ITER is often presented as the long-term solution to the problem of global warming, because nuclear fusion can provide an infinite and clean source of energy. But ITER will do nothing of the sort.
In the fission reactions that nuclear power generation relies on today, heavy elements such as uranium break into smaller ones, while in nuclear fusion small elements such as hydrogen stick together and form heavier elements (helium). Both fission and fusion produce a lot of energy.
Some political leaders explain that nuclear fusion is at work in the sun, and that, thanks to ITER, we will harness it. They often add that, since fusion burns hydrogen, which can be found in seawater, it is an infinite source of energy.
Unfortunately, political leaders know little about the scientific issues involved. That nuclear fusion is a source of energy has been known since the invention of the hydrogen bomb. But its control is still a fundamental challenge for research institutes, not some minor technical difficulty that can be easily overcome.