Warming Climate Could Result in a More Flammable Arctic Tundra
06.03.2008 - Other
By studying sediment cores, scientists from Montana State University determined that the Arctic tundra was covered with vast expanses of tall birch shrubs after the last ice age. They also found out that those shrub expanses burned quite frequently. If this were to happen today, these tundra fires would release a significant amount of organic carbon into the atmosphere. Other evidence indicates that tall shrubs have expanded across the world's tundra regions, a consequence of climate warming over the past 50 to 100 years.
By looking at fossilized pollen grains found in sediment cores of four Alaskan lakes, scientists determined that the Arctic tundra used to be very different from what it is now after the last ice age. Instead of being covered with grass, herbs, and short shrubs, it used to be covered with vast expanses of tall birch shrubs. Charcoal preserved in the sediment cores also showed evidence that these shrub expanses burned quite frequently.
The world's high latitude tundra and boreal forest ecosystems contain roughly 30 percent of the planet's total soil carbon. Vegetation change through an increase in shrub biomass and more frequent burning could cause enormous change in the carbon cycle of these high latitudes.
