Study Connects Climate To Carbon Content In Soil
A new study by the University of Florida (UF) has found that the state’s hot, humid climate has a beneficial effect on soil’s ability to hold down greenhouse gas carbon emissions
Carbon trapped in moist soil helps slow the build up of carbon-based gasses in the atmosphere, so it’s important to preserve it, according to Sabine Grunwald, a water science professor at UF’s Institute of Food and Agricultural Sciences (IFAS) who led the research.
“The conservation of the ‘black gold’ below our feet – which is not only a natural part of Florida’s soils but also helps to improve our climate and agricultural production – is a hidden treasure,” Grunwald said. “Soils serve as a natural container to hold carbon that would otherwise be emitted into the atmosphere as greenhouse gases.”
Florida is florid because it’s wet, and over the years more carbon has been absorbed by its soil than in any other U.S. state — unless you include Alaska, whose carbon-retention capacity isn’t known because its soil hasn’t been studied as extensively.
Meanwhile, in the past 45 years, Florida’s population has more than tripled from 5 million to about 18 million today. Grunwald says this has caused a major change in land use, with growth in urban areas and declines in forests, rangeland and farmland.
While that may sound bad for the environment, it’s good for the atmosphere because wetlands, which hold a lot of carbon, have increased by 140 percent, while farmland, which is low in carbon, has decreased by about 20 percent, according to Grunwald’s study, which is the first of its kind and was published in the journal Science of the Total Environment.
The research team studied information from 1,251 soil samples from throughout the state from 1965 to 1996, and collected new samples statewide in 2010. That way they were able to study how Florida’s soil holds on to carbon – called “soil carbon sequestration” – over 45 years.
Their study found that, together, land use, land cover and recent warming from climate change make up for 46 percent of soil carbon sequestration, including 27 percent from land cover and land use and 19 percent from climate change.
The team relied on rainfall and temperature to measure how climate change affects sequestration. They learned that the recent higher average temperatures correspond with higher sequestration, though greater rainfall tended to show less sequestration. They found that crops grown in agricultural wetlands stored the most carbon, while crops requiring drier soils sequestered the least.
By Andy Tully of Oilprice.com