A new LMU study shows the extent to which human influence is altering natural land carbon stocks.
Human activities, such as deforestation and the expansion of agricultural areas, have a massive impact on the natural state of ecosystems. As a result, large amounts of carbon are released into the atmosphere, contributing substantially to anthropogenic climate change.
A team led by LMU geographer Raphael Ganzenmüller has now calculated that human influence has reduced natural land carbon stocks by a total of 24 percent – which corresponds to 344 billion metric tons of carbon.
By combining high-resolution Earth observation data with historical and current land use data and machine learning, the team created a detailed global estimate. The researchers were also able to show that most of the loss is caused by the expansion of pasture and croplands, as well as forest management.
"Our study reveals the far-reaching human impact on the global carbon cycle," explains Raphael Ganzenmüller. "The deficit of 344 billion metric tons of carbon is comparable in size to global CO2 emissions from coal, oil, and natural gas over the past 50 years. Our approach provides a clear picture of where and how vegetation and soils have been degraded and can be used as a general indicator of the state of ecosystems."
Julia Pongratz, Professor of Physical Geography and Land Use Systems at LMU, adds: "Our study provides important insights for climate policy. For example, the findings can be used to evaluate carbon removal measures. Moreover, they underscore the great potential of restoring carbon stocks on land to achieve global climate goals."
The findings are relevant for both policymakers and scientists: They provide an important basis for prioritizing the conservation and restoration of carbon sinks and offer opportunities to improve existing climate models and their projections.
