The Cold War's wildest dreams of climate control have made a spectacular comeback: from the USA to China, 'geo-engineers' promise to make climate change the way we want. And they have found powerful supporters among lobbyists and entrepreneurs. This film is an investigation into the world-wide boom in geo-engineering. How did a pseudo-science with a controversial past become a planet-wide research subject?

ACID TEST explores “the other carbon problem” – the startling phenomenon of ocean acidification, which could challenge the health of the ocean ecosystem on a scale that has not occurred for tens of millions of years.