The world is banking on giant carbon-sucking fans to clean our climate mess. It's a big risk.

Updated 0914 GMT (1714 HKT) October 20, 2021

Hellisheiðarvirkjun, Iceland (CNN)The windswept valleys surrounding the Hengill volcano in southwestern Iceland are dotted with hot springs and steam vents. Hikers from all over the world come here to witness its breath-taking scenery. Even the sheep are photogenic in the soft Nordic light.

Right in the middle of all that natural beauty sits a towering metal structure resembling four giant Lego bricks, with two rows of six whirring fans running across each one. It's a contraption that looks truly futuristic, like something straight out of a sci-fi film.
Humans have emitted so much carbon dioxide (CO2) into the atmosphere that machines like this are being used to literally suck the gas back out, like giant vacuum cleaners, in an attempt to slow the climate crisis and prevent some of its most devastating consequences.
The Orca plant — its name derived from the Icelandic word for energy — is what is known as a "direct air carbon capture facility," and its creator and operator, Swiss firm Climeworks, say it's the world's largest.
Climework's Orca project at the Hellisheiði Geothermal Power Plant in Iceland opened last month.
Dr. Edda Aradóttir is a chemical and reservoir engineer and the CEO of Carbfix.
The aim of Orca is to help the world reach net zero emissions — where we remove as much greenhouse gas from the atmosphere as we emit. Scientists say that simply cutting back on our use of fossil fuels won't be enough to avert catastrophe; we need to also clean up some of the mess we've been making for hundreds of years.
Orca is a depressing symbol of just how bad things have become, but equally, it could be the tech that helps humanity claw its way out of the crisis.
"We, as humans, have disturbed the balance of the natural carbon cycle. So it's our job to restore the balance," said Edda Aradóttir, a chemical engineer and the CEO of the Icel