The United Nations Climate Change Conference in Paris in December will feature all the tightly choreographed production values of a Hollywood blockbuster. The cast will be huge: presidents and prime ministers at center stage, supported by thousands of extras, including protesters, riot police and busloads of media. The script may still be under wraps, but the plot has already leaked: This time, in sharp contrast to the failed negotiations in Copenhagen in 2009, the planet is going to win.

It is a seductive plot, but one that does not quite hold together. Goodwill and hard bargaining, the world will be told, paid off. Governments have agreed to voluntary reductions in greenhouse-gas emissions that will prevent the planet from heating more than 2 C. Then, in a stunning deus ex machina, it will be revealed that the world's largest fossil-fuel companies — the so-called supermajors — have agreed to bring net emissions to zero by 2100, by capturing carbon at the source, sucking it out of the atmosphere and storing it underground. The planet will have been saved, and the economy will be free to flourish. Cue the music and roll the credits.

The trouble is that the script is fiction, not documentary. The technology required has yet to be invented, and bringing net emissions to zero simply is not possible. And, like a Hollywood production, the Paris conference's message will have been heavily influenced by those who have the most money.