Forests in at least 10 World Heritage sites have become net sources of carbon, due to pressure from human activity and climate change, according to a new report by the UN Educational, Scientific and Cultural Organization (UNESCO). The agency’s new analysis, World Heritage forests: Carbon sinks under pressure , shows that instead of helping mitigate global warming, some of the world’s most treasured forests are in fact adding to overall CO2 emissions. The first ever scientific assessment of greenhouse gas emissions in forests on the UNESCO World Heritage list, has found that since the turn of the millennium, some forests such as the Yosemite National Park in the United States, and the Rio Platano Biosphere Reserve in Honduras, have released more carbon that they sequestered due to wildfires, deforestation and global heating.