If we can get fusion to work, it would solve the world's energy problems and stop carbon dioxide build up, maybe even give us enough energy to run an intensive program to reverse it. It's a difficult question as to whether that would be a good thing. For example, it might result in uncontrolled population growth, with the remaining wild environment being destroyed to accommodate them and their food needs. Security achieved at the cost of most of the remaining beauty in the world, and people dehumanised, living like maggots in an angler's tub.

It may be though that fusion already has been discovered, but missed. Cold fusion was "found", then discredited twenty years ago, but every 10 years or so for the last seventy someone has come up with a secret patent method of "burning water" (the lastest was only a few weeks ago). Everybody knows you can't do that, or at least can't get out more energy than you put in to separate the H and O. Unless there is something else involved.

In the 1890s the Scottish scientist Lord Kelvin "proved" that the Earth couldn't be more than 24 million years old according to classical physics. But just as he'd laid physics to rest as complete, nuclear sources of heat were discovered that confounded his estimate and extended the potential age to billions of years.

It's possible (if unlikely in the present state of knowledge) that there is some natural small- scale fusion reaction that could account for the apparent excess energy found- and the fact that someone is a charlatan doesn't mean he's necessarily wrong!