Billionaire entrepreneur Elon Musk has offered inventors $100m in prize money to develop ways to fight global warming by removing carbon dioxide from the atmosphere or ocean. Al Jazeera explains that carbon capture projects have already drawn backing from Silicon Valley startups, public officials worried about the slow pace of cutting emissions and emitters including oil companies seeking to offset their effect on the climate but the technology is not yet commercially viable. Musk’s $100m XPRIZE Carbon Removal is aimed at finding a viable solution for taking 1,000 tonnes out of the atmosphere annually, with the potential to scale up dramatically. Contenders must also have a plan to sequester carbon for at least 100 years.