"Coastal and river delta areas around the world are suffering from a number of problems, including hypoxia created by effluents entering the river systems from cities and agriculture. Fresh water supplies are under severe pressure in some parts of the world."
The main frustration for Nelson was the lack of reliable information.
"What I found most shocking was just how bad our information set is on something like the expansion of agricultural land," he said. "One would think that would be relatively easy to trace but when researchers began reporting what we could find out about land-use change between 1980 and 2000 we found all sorts of problems."
The problems stem from limited data collection efforts and incorrect interpretation of data that do exist. One consequence was an early draft map indicating that areas of recent rapid agricultural expansion took place in such unlikely locales as the U.S. northern Great Plains, Ireland, and Java.
"We simply don't have good information on what I thought would be the easiest changes to document," Nelson said. "It turns out that globally we have an abysmal system to collect data needed to assess the state of the world's ecosystems.
"That failure is a big problem because if you don't know what you are doing, especially the bad things, you can't fix them."
While the study has a global focus, Nelson also said the study highlights some possible future concerns for Illinois.
"Local climate change, following from global climate change, may necessitate changes in cropping patterns, even if farmers stick with corn and soybeans," he said. "Water shortages around the world will mean 'exporting' Illinois water in the form of agricultural products.'"/>