London (CNN)It's a stark prognosis: To save the world from the worst effects of climate change, it's likely not enough to cut carbon dioxide emissions; we need to start scrubbing carbon pollution from the atmosphere, too.
Can this carbon capture technology save us from climate change?
And not just a little bit of carbon. Vast amounts of it.
The problem is, the jury is still out on whether that's even possible.
Last month, a report from the global authority on climate science, the Intergovernmental Panel on Climate Change (IPCC), warned of the catastrophic consequences likely to result if humans cause global temperatures to rise more than 1.5 degrees Celsius above pre-industrial levels. The group also said that if we want to stay below the 1.5 degree limit, we'll need to use technologies that remove carbon dioxide (CO2) from the air.
But the report noted that carbon removal at the scale that's likely required is "unproven and reliance on such technology is a major risk in the ability to limit warming to 1.5°C." In other words, don't solely bank on an unproven technology when your future is on the line.
Just how much CO2 we need to pull from the air depends on how much of that heat-trapping gas we keep pumping into the atmosphere.
If we fail to make dramatic cuts -- which is how things stand with current global emissions pledges -- by the end of the century we might need to remove a total of around 30 times the CO2 that the world currently emits each year, according to the IPCC report.
There are many methods we might use to remove CO2 from the air, from the low-tech -- simply planting more trees -- to the speculative -- adding iron to the oceans to speed the uptake of atmospheric CO2 by microscopic plant life.
But one method that's got a lot of attention from IPCC scientists is known as Bioenergy with Carbon Capture and Storage, or BECCS. Essentially, it means growing bioenergy crops and then burning them at power stations to create energy, while capturing the CO2 that's emitted.
When the bioenergy crops grow, they absorb carbon dioxide from the atmosphere. As long as the CO2 captured when they are burned is safely stored, the process is considered carbon negative.
Of course, it's not quite that simple. Growing, collecting, transporting and processing the crops will hav