 One of the difficulties in understanding the large-scale consequences associated with climate change is, quite simply, seeing what is happening. Curtis Woodcock, a geographer associated with the Center for Energy and Environmental Studies and the Center for Remote Sensing, has approached the problem by using satellite imagery and GIS (Geographic Information Systems) data to examine and forecast the impacts of land-use changes on the carbon cycle.
After more than 25 years in the field, Woodcock says that improved satellite imagery and more powerful computer technology have allowed researchers to study larger areas more efficiently and accurately. He credits the designers of the original Landsat imaging technology for building a system that has provided scientists with an invaluable record of images, documenting changes on the Earth’s surface for more than 30 years.
Woodcock focuses on understanding how changes in a particular piece of land alter the way carbon “flows” through that ecosystem. “If you watch the way the world is changing, reforestation is occurring in some places, like New England,” says Woodcock, “while at the same time deforestation is happening in the tropics.” With each change made by man—the planting of a field of corn or construction of a parking lot—comes a change in the carbon dynamics of that piece of land. Individually, these alterations may or may not be significant. But when such changes are looked at cumulatively, on a regional or global scale, they may have a pronounced impact on ecosystems and climate patterns.
His current work is focused on the area surrounding the Black Sea in Georgia, Ukraine, Bulgaria, Romania, and Turkey. His work is made more challenging by the influence of human development in the area. In the former Soviet-bloc state of Romania, for example, Woodcock has observed the impact of social upheaval on the landscape. Using a series of NASA’s Landsat satellite images that begin before the collapse of the Soviet Union, Woodcock has observed large, single-crop communes carved up into smaller individually controlled plots. The change in land utilization means a change in the way that carbon flows in and out of the ecosystem. “The fall of communism marked a drastic change in the land use and carbon dynamics of the region,” says Woodcock.
 Even as research is moving ahead, there are uncertainties about the global carbon cycle, a complex series of processes in which carbon circulates between the Earth and its atmosphere. Plants, both terrestrial and aquatic, absorb carbon dioxide (CO2) from the atmosphere and through photosynthesis incorporate, or sequester, carbon atoms into their biomass. Fossil fuels, produced millennia ago by natural processes that put organic material under enormous pressure, contain large quantities of sequestered carbon. As they breathe, or respire, both plants and animals release CO2, returning a small portion of their carbon to the atmosphere, but most of the carbon stored as biomass is released only when it decomposes or burns. The different places where carbon is accumulating—the soil, vegetation, and fossil fuels—are called carbon sinks.
Current models of atmospheric concentrations of CO2, for instance, cannot balance the incoming and outgoing CO2, as input exceeds output. According to Woodcock, finding this “missing sink” is a common goal among carbon cycle researchers. Of the approximately 7.5 gigatons of CO2 added to the atmosphere each year through tropical deforestation and the burning of fossil fuels, the fate of nearly 2 gigatons remains uncertain. There are competing theories as to where the carbon is going. Some say it is dissolved in the rivers of the Amazon; some say it is absorbed in the boreal forests and tundra of the northern latitudes.
One thing that carbon cycle scientists do agree on is that the continued unchecked burning of fossil fuels, and the freeing of the carbon in the estimated 4,000 gigatons of fossil fuel remaining, have the potential to cause even more catastrophic shifts in global climate.
Like much climate research today, Woodcock’s work has major policy implications. However, he dismisses the idea that climate science has been politicized. “Anyone who works in the field is serious about their work. Politics does not influence our research or our conclusions,” he says. Woodcock also says that his work has ramifications beyond the sphere of climate change. “The study of land use tells us much about the overall health of our planet, about human impact on biodiversity and on natural systems across the planet.” To these ends, he works with Global Observation of Forest and Land Cover Dynamics, or GOFC-GOLD, an international organization working to improve the land-use data available to land managers and researchers.
For more information, see www.bu.edu/geography/people/faculty/woodcock.
— by Jeremy Miller |
