Warmer conditions on the tundra trigger a cascade of change, including converting its lush but short green carpet into a taller shag, since warmer soils and deeper thaw enable taller, woody plants to grow and thrive on the tundra.
During this single event, the immediate combustion of plants and soils and the thawing of frozen soils injected an enormous amount of carbon into the atmosphere an amount equivalent to what the entire tundra biome typically absorbs from the atmosphere through plant growth every year.