Farms in the North release massive amounts of carbon

Extensive parts the peat stretches to the northern end of our planet, decomposing the accumulated organic material that is too wet. Although peatlands make up only 3% of the total surface area of ​​the Earth, they store a third of the Earth’s carbon. Climate scientists are concerned: As the Arctic warms, they are drying up and releasing large amounts of carbon. People are accelerating this process by emptying the peatlands and turning them into agricultural fields, emitting more greenhouse gases.

Lately paper in the magazine Advances in Science, researchers put a large amount to the effect of agriculture in these areas: Modeling the historical use of the land, they estimated that between 1750 and 2010, cultivated peatlands in the north released 40 billion tons of carbon.

“When the peat dries, that is, people drill drainage ditches to allow the peat to have a better water level to grow crops. , wrote the lead author Chunjing Qiu, of the French Laboratory of Climate and Environmental Sciences and the University of Paris-Saclay, in an email to WIRED. New plant material that grows and dies there will quickly deteriorate, releasing carbon because there is not enough water to slow down the process of converting organic material to CO.₂.

Traditionally, climate scientists have focused on how much carbon we are losing due to deforestation, but they have often not investigated the effects of turning peatlands into fields. “We haven’t always done a good job of accounting for how much carbon is being lost ground system, ”says soil scientist Maria Strack, who studies peatlands at the University of Waterloo but has not been involved in the study. we underestimated their contribution to the spills. “

Humanity, therefore, is becoming a critical carbon sink source number of emissions. Underlying this conversion are, of course, the social actors: as the population grows, nations need to feed more people with the same amount of land. Economically, it makes sense for farmers to once wet their soaked surfaces into cropland. “It creates fairly fertile soil, but you’re losing carbon at the same time,” says Chris Evans, a biogeochemist at the UK Center for Ecology and Hydrology, who was not involved in the new paper. “Because a lot of carbon is being lost from some of these landscapes, they’re kind of empty carbon storage units, really.”

Agricultural processes only accelerate this loss. Planting dried peat allows more oxygen to enter, which further promotes the conversion of organic material into CO₂. Responsible microbes will proliferate even further if farmers add fertilizers that they supply with additional nutrients. In a moist, healthy peat bog, the plant material it produces must be glued and, once it dies, it must be inserted into wet soil, as carbon will be trapped for perhaps thousands of years. But on a farm, the crops that the land produces are uprooted and sold.

It will be irrigated by farmers working in actively cultivated peatlands, keeping the soil at least wet enough to grow the plants. But then if the earth is abandoned and left to dry completely, it will become a bad fuel for fires. Because peat is a concentrated carbon, it burns easily, but you won’t see it as a massive conflict. California or Australia. Instead of creating flames, peat fires burn deeper in the ground and move through a landscape. Peat fires are so persistent that they can survive underground in winter as they fall above the snow reappear when the landscape thaws in the spring. That’s why scientists call them zombie fires. They can release it The amount of carbon is 100 times higher that it could be caused by a fire on the ground.

Nature is also drying up peatlands on its own as the northern lands heat up. Arctic in its entirety it is turning green as a plant species march north as a result of climate change. As a result of the hot temperatures, storms are becoming more common, giving off sparks to ignite large peat fires: by 2100, lightning in the north could be doubled.

Therefore, it is very important for farmers to recover previously cultivated peatlands. “In addition to reducing oxidation emissions, you’ll reduce the risk of fire,” says Strack.