MEGAN ROWLING LEADERS of G7 wealthy nations have said that 2021 should be a "turning point for our planet", faced with an "existential threat" from the twin crises of climate change and biodiversity loss. In a joint communique at the end of a summit in Britain, they agreed to support "a green revolution that creates jobs, cuts emissions and seeks to limit the rise in global temperatures to 1.5 degrees" above pre-industrial times. They said they would cut their climate-heating emissions to net-zero by 2050, halve their collective emissions by 2030 from 2010 levels, and boost climate finance for developing…