Climate change: how elephants help pump planet-warming carbon underground
Imagine you’re in a hot air balloon flying over an African savanna in the late growing season. Below, herds of elephants, zebras, wildebeests and rhinos roam a mosaic landscape dotted with lonesome trees and daubs of woodland on a canvas of yellow-brown grass. The hungry and rowdy herbivores are eating and trampling the vegetation that stores carbon and keeps it from heating the atmosphere.
You’d be forgiven for thinking that their voracious appetites and blundering steps might be disturbing and releasing the carbon stored in this ecosystem in much the same way wildfires do. But, incredibly, the way herbivores disturb the landscape actually helps it lock up more carbon in durable stores that are difficult to reach. In a new review which compiled evidence from lots of different studies, we uncovered how large herbivores could help slow climate change this way.
Forests are often evoked as the ultimate vessels for storing carbon. But carbon in the bark and leaves of trees is vulnerable to logging, pests and fires which can unleash decades of accumulated carbon in a matter of hours. Even in healthy forests, most of the carbon stored in vegetation above ground is decomposed and recycled to the atmosphere as greenhouse gas in less than a century.