Scientists agree that to keep global temperatures in check, the world needs to reach either net zero or even negative carbon emissions. To do that, it will need to focus on certain industries.
The aviation, shipping, steel and cement industries represent the biggest chunk of hard-to-remove emissions worldwide. Spikes in daily energy demand make up a large chunk, too. Together in 2014, they accounted for 27 percent of global CO2. That number could only grow, as demand is increasing.
An international team of researchers weighed a list of potential solutions — things like biofuels instead of petroleum, cleaner electric furnaces for steel production, or grid-scale energy storage. They found one of the most important things to do, regardless of industry, is to prevent carbon from entering the atmosphere in the first place.
It's called carbon capture and storage: CO2 is filtered out of emissions right at the origin point and pumped underground so it can't get to the atmosphere.
The technique is relatively new and expensive. It's only been deployed to a couple of plants on a large scale. But scientists and energy experts think the success of those other solutions on their list depends on carbon capture working.
And it has the potential to be really effective. Biofuels come from plants, so they capture carbon as they grow. If they're combined with underground carbon storage when the fuels are burned, the industry might even draw more carbon out of the air than it puts in.
Capturing carbon straight from cement plants could cut out most of those emissions, and the cement itself might get the rest of them. Its chemicals react with carbon in the air around it over the course of its life.
And adding carbon capture to fossil power plants makes them pollute less when they're ramping up to meet demand. That buys more time for storage tech to develop, which could help address the biggest remaining slice of the world's persistent CO2.