Christian Science Monitor: Billions of tiny mountain pine beetles are treating Canada’s boreal forest like a 3,000-mile-long salad bar, transforming a key absorber of carbon dioxide greenhouse gas into a CO2 emitter instead. In just a decade, exploding beetle populations and a rise in wildfires have flipped Canada’s boreal forest from its longstanding role as a natural carbon vacuum – sucking up 55 million or more tons of CO2 annually – to that of a giant tailpipe emitting up to 245 million tons of CO2 each …