Even modest climate change imperils northern forests

PARIS: Even relatively moderate heating and rainfall loss could dramatically alter the make-up of Earth’s northern forests, risking their biodiversity rich ecosystems and undermining their ability to store planet-warming carbon pollution, researchers said on Wednesday.

Boreal forests cover much of Russia, Alaska and Canada and are a major carbon sink, but they are menaced by more frequent wildfires and invasive species outbreaks linked to climate change.

To assess how higher temperatures and less rainfall may impact the tree species most commonly found in the forests, a team of researchers based in the United States and Australia conducted a unique five-year experiment.

Between 2012-2016 they grew some 4,600 saplings of nine tree species -- including spruce, fir and pine -- in forest sites in northeastern Minnesota. Using undersoil cables and infrared lamps, the saplings were warmed around the clock at two different temperatures -- one lot at 1.6 degrees Celsius hotter than ambient, the second at 3.1C warmer.

In additional, moveable tarps were positioned over half the plots before storms to capture rainwater and mimic the type of precipitation shifts that climate change is anticipated to bring.