Boreal Forests: Our Threatened Carbon Sinks
In the world of climate science, much study exists concerning climate tipping points. Tipping points refer to event(s) that indicates that the earth’s climate has irreversibly changed; possibly the most well known proposed tipping points are the melting of the Arctic and Greenland ice sheets or rising global temperatures. In climate change scenarios, tipping points launch positive feedback loops where climate disruption effects trigger furthering and worsening events, which in-turn, trigger even worse events, and so on. Though melting ice receives a large portion of study and media attention, other climate change events receive little to no media attention. One such event is boreal forest dieback.
Boreal forests, also known as the taiga, are the world’s largest terrestrial biome, covering about 15% of the earth’s surface. Boreal forest biomes act as carbon sinks for the world’s atmosphere, which means that the biome actually sequesters carbon from the air. However, as climate disruption worsens, boreal forests switch from being carbon sinks to huge greenhouse gas emitters. Unfortunately, these events have already begun, particularly in the Eurasian boreal forest. Several indicators have shown that the world’s taiga is in trouble.
El Niño and Arctic Oscillation play a big role in determining temperatures and how much precipitation the taiga will receive. Global temperature rise have caused both Arctic oscillations and El Niño to bring lower rainfall and higher temperatures throughout the year. This has led to a more active fire season in Eurasian boreal forests; additionally longer fall and spring seasons have shortened the winter freeze and led to more sun exposure on methane filled permafrost and ice.
Between 2001 and 2003, forest fire activity tripled in area from 27,000 square kilometers to 81,000 square kilometers; burn areas have only continued to grow since then. The world was exposed to the devastating effects of boreal forest burns in 2010 when Russian forest fire air quality killed an estimated 56,000 people in Moscow and surrounding areas over the span of several months. Boreal forest fires not only affect local air quality, they release higher volumes of methane from melted permafrost which speeds up climate disruption processes. Methane persists in the atmosphere for less time than carbon dioxide (which is also released during forest fires), but it has 24 times the insulting power of carbon dioxide. In addition to methane from melted permafrost, frozen taiga lakes trap methane air bubbles in the ice which are released into the atmosphere when ice melts. Rising global temperatures create the necessary conditions for ice and permafrost to release their methane.
Though the Eurasian boreal forests are extremely damaged, the Canadian boreal forests remain in decent health. Unlike the Russian taiga, the Canadian boreal forests still acts as a carbon sink, but for how long? Global temperature rise poses the same risk to Canadian boreal forests as Eurasian forests; also, mining development in tar-sand deposits in Northern Canada stand as a huge threat to the health of the biome. Boreal forest dieback must become a better known issue for the general public; their deterioration has already begun, but efforts to save the biome have been limited. If conservation efforts do not improve, climate disruption could become unstoppable and boreal forest could become a thing of the past.
Photo Credit: wikispaces.com/file/view/boreal-forest-arctic-circle-701234-ga.jpg/32308017/boreal-forest-arctic-circle-701234-ga.jpg