When it comes to saving the world’s rainforests, governments can make a big difference, and fast. Take Indonesia, which in 2012 surpassed Brazil as the world’s leader in tropical rainforest destruction. In 2017, it engineered a 60 percent drop in tree loss from the previous year by strictly enforcing protections in vulnerable regions. On the other hand, governments can reverse course just as swiftly. Take Brazil, where a decade-long trend of improving forest protections has now gone into reverse. It’s a concern both in and beyond the tropics, with multinational companies coming under increasing pressure to stop doing business with suppliers that ravage the environment. Rainforests host half the species on Earth, help regulate global weather patterns and produce much of the planet’s oxygen. Their disappearance, through burning or felling, creates about 10 percent of the greenhouse gases the world produces in a given year that drive climate change. By one estimate, more tropical tree cover was lost globally in 2016 and 2017 than in any other years this century.