"Up to now, the main focus of the artificial photosynthesis community [has been] solar fuels," using sunlight and carbon dioxide to produce liquid fuels, May said. The problem is that when solar fuels are burned, the carbon stored within is returned to the atmosphere. May's proposed approach, however, offers a way to store that carbon underground. So, instead of recycling heat-trapping carbon dioxide, scientists would be burying it away, cooling the planet. For now, however, carbon capture in any form remains impractical and expensive. Curbing the use of fossil fuels remains the cheapest and most effective way to curb climate change.