Six feet under, a new approach to global warming
(Researcher sees how deep soil can hold much of the Earth’s carbon)
At least a quarter of all the carbon stored in Earth’s soil is found locked up in minerals roughly six feet beneath the surface. But new research suggests this unique carbon reservoir will become less efficient at carbon storage as the planet warms. To better understand how rising carbon dioxide levels in the atmosphere will impact the planet’s climate, scientists need to more accurately model Earth’s many carbon cycles. Soil hosts one of those carbon cycles. As part of a new survey, the first of its kind, researchers detailed the way carbon physically and chemically binds to minerals in soils across the globe.
“We know less about the soils on Earth than we do about the surface of Mars,”. “Before we can start thinking about storing carbon in the ground, we need to actually understand how it gets there and how likely it is to stick around. This finding highlights a major breakthrough in our understanding.”
After analyzing climate data and soil samples collected at 65 different dig sites in the Americas, New Caledonia, Indonesia, and Europe, researchers created a global map of soil-based carbon sequestration. The new data showed minimal amounts of carbon are stored in the sediments of deserts and dry forests, but roughly six feet beneath the surfaces of wet forests, scientists found an abundance of carbon bound to reactive minerals. The persistence of water and decaying organic matter on the forest floor helps leach carbon from above and transport to minerals buried below.
“This is one of the most persistent mechanisms that we know of for how carbon accumulates,”. According to the new research, global warming won’t impact the carbon that is already stored beneath the surface of wet forest floors, but it will alter the pathway by which new carbon gets stored. Temperature increases are likely to minimize the amount of water running through forest soil, even if precipitation levels remain stable.