Yearly carbon emissions from the world's forests have dropped by more than 25% in the last 15 years, a UN agency said. The decrease in annual emissions, which cause global warming, is largely due to slowing rates of global deforestation, the Food and Agriculture Organisation (FAO) reported.Forests hold about three-quarters as much carbon as the atmosphere and preserving them is crucial for combating climate change."Deforestation and forest degradation increase the concentration of greenhouse gases in the atmosphere, but forest and tree growth absorbs carbon dioxide, the main greenhouse gas emissions," FAO director-general Jose Graziano da Silva said.Emissions from deforestation decreased to 2.9 gigatonnes of carbon dioxide from 3.9 gigatonnes between 2001 and 2015, the FAO said.Brazil, Chile, China, Cape Verde, Costa Rica, the Philippines, Turkey, Korea, Uruguay and Vietnam have all seen net decreases in deforestation, Da Silva said.Africa, Asia and Latin America and the Caribbean all continued to release more carbon than they absorb. Total emissions from Africa and Latin America, however, decreased between 1990 and 2015, the FAO said. ..