Improved knowledge of global carbon cycling at the dryland regions level is the goal of an Indiana University geography professor’s NASA-funded research.

“Given the importance of drylands globally, it’s significant that we fully understand dryland ecosystem processes,” Natasha MacBean, an IU assistant professor of geography, told Indiana Environmental Reporter. “There are complex interactions between vegetation, carbon and water cycles in drylands and how those processes respond to changes due to climate as well as land management that are not yet fully understood.”

Dryland regions are water-limited ecosystems that make up about 40% of the Earth’s surface and support two-thirds of the world’s population. These regions are found in the U.S., Australia, South America, Africa and in central Eurasia.

“These areas are under a lot of pressure from a variety of sources such as a growing population, land misuse and a lot of extraction of ground water,” she said. “They are also often converted to one-crop growth when other sustainable growth makes sense.”
Research should result in a significant improvement in the ability to map vegetation cover at large scales using remote sensing data, a greater understanding of processes based on field and satellite data analysis, and modeling of those processes.

The specific focus of this research is important in understanding the global carbon cycle.

“At global scales, terrestrial ecosystems currently absorb about 30% of our CO2 emissions into the atmosphere from fossil fuels. But beyond knowing that -30% discount on our emissions at global scale, there are a lot of remaining questions on which ecosystems and which specific carbon cycle related processes are controlling that global carbon sink,” MacBean explained.

Several high-profile papers have suggested that drylands are controlling the year-to-year variability in that sink as well as its long-term trend, she added. But there’s a need to study dryland carbon cycling more to fully understand if that's true and to ensure the right processes are implemented in models to be able to ask if drylands really do control that year-to-year variability of the global carbon cycle.

“Our research will be a significant step forward to achieving this goal of understanding dryland carbon cycling at large scales and implementing that knowledge in models,” MacBean said.

The three-year investigation, which is funded by a $900,000 NASA grant, is being led by MacBean and includes staff from the U.S. Geological Survey, University of Arizona and NASA.