Global warming is driving leafy tropical canopies close to temperatures where they can no longer transform sunlight and CO2 into energy, threatening total collapse if the thermometer keeps climbing, according to a study Thursday.If tropical forest's average surface temperature warms 4C above current levels widely considered a worst-case scenario "we're predicting possible total leaf death," he said.
Small but significant proportion of leaves in tropical canopies are experiencing temperatures of 46.7C or above, at which point their survival is threatened