Direct air capture

When soaring temperatures, extreme weather and catastrophic wildfires hit the headlines, people start asking for quick fixes to climate change. The U.S. government just announced the first awards from a US$3.5 billion fund for projects that promise to pull carbon dioxide out of the air. Policymakers are also exploring more invasive types of geoengineering − the deliberate, large-scale manipulation of Earth’s natural systems. The underlying problem has been known for decades: Fossil-fuel vehicles and power plants, deforestation and unsustainable agricultural practices have been putting more carbon dioxide into the atmosphere than the Earth’s systems can naturally remove, and that’s heating up the planet. Geoengineering, theoretically, aims to restore that balance, either by removing excess carbon dioxide from the atmosphere or reflecting solar energy away from Earth. But changing Earth’s complex and interconnected climate system may have unintended...

Deep below the ocean surface, the light fades into a twilight zone where whales and fish migrate and dead algae and zooplankton rain down from above. This is the heart of the ocean’s carbon pump, part of the natural ocean processes that capture about a third of all human-produced carbon dioxide and sink it into the deep sea, where it remains for hundreds of years. There may be ways to enhance these processes so the ocean pulls more carbon out of the atmosphere to help slow climate change. Yet little is known about the consequences. Peter de Menocal, a marine paleoclimatologist and director of Woods Hole Oceanographic Institution, discussed ocean carbon dioxide removal at a recent TEDxBoston: Planetary Stewardship event. In this interview, he dives deeper into the risks and benefits of human intervention and describes an ambitious plan to build a vast monitoring network of autonomous sensors in the ocean to help humanity understand the impact. First, what is ocean carbon...

Several major airlines have pledged to reach net-zero carbon emissions by midcentury to fight climate change. It’s an ambitious goal that will require an enormous ramp-up in sustainable aviation fuels, but that alone won’t be enough, our latest research shows. The idea of jetliners running solely on fuel made from used cooking oil from restaurants or corn stalks might seem futuristic, but it’s not that far away. Airlines are already experimenting with sustainable aviation fuels, including biofuels made from agriculture residues, trees, corn and used cooking oil, and synthetic fuels made with captured carbon and green hydrogen. United Airlines, which has been using a blend of used oil or waste fat and fossil fuels on some flights from Los Angeles and Amsterdam, recently announced plans to power 50,000 flights a year between its Chicago and Denver hubs using ethanol-based sustainable aviation fuels by 2028. The airline also launched a US$100 million fund on Feb...