BOULDER—Scientists have taken the first crack at solving a fundamental climate mystery, criss-crossing the globe in a souped-up corporate jet to determine where and when greenhouse gases enter and leave the atmosphere.
An understanding of how these climate-warming gases move about the globe is a critical prerequisite for any policy aimed at curbing global warming, scientists said Thursday, and information gained over the next three years will play a crucial role in sharpening future predictions and improving their accuracy.
Using a high performance jet, scientists will take a series of "slices" of the atmosphere over the next few years from pole to pole and from the surface to the atmosphere's upper reaches.
They are expected to return from their first mission this week—a series of 11 flights from Colorado to the Arctic Circle to Tahiti, Antarctica, Easter Island and Costa Rica. Scientists running the instruments say they have seen several "wonderful jewels" in the raw data that challenge current thinking and assumptions.
When all the measurements are assembled, scientists added, they will for the first time have a picture of the atmosphere—and a global snapshot showing where and when some of the estimated 30 billion tons of carbon emitted annually by cars, factories, deforestation and other human activities enters the atmosphere.
"We were essentially retracing Captain Cook's voyages—obviously much later and with much more sophisticated instruments, but with some very similar parallels," said Britton Stephens, a scientist with the National Center for Atmospheric Research and one of the project's principal investigators.
"When he set sail, he knew the ocean was out there, but didn't really know the details. Similarly, we've been standing on the edge of the atmosphere—the surface—but we don't really know the details."
Researchers expect the $4.5 million mission to provide several critical answers to atmospheric riddles, but the two most important are fundamental to any effort to curb climate change, team members said during a conference call with reporters near the end of the first of five missions:
First, the project will fill key gaps in our understanding of how carbon cycles through the atmosphere and among the earth, air and oceans. Roughly half the carbon emitted by humans stays in the atmosphere, with the remainder being absorbed by ocean and earth ecosystems. But scientists don't understand how the system works or how quickly various gases mix.
The result, Stephens said, is that models of this so-called carbon cycle grown wildly divergent as they are projected into the future, with nearly 100 percent uncertainty by 2050.
Second, and perhaps most important, the map will provide a baseline against which efforts worldwide to curb carbon emissions can be judged. Need for such a benchmark has gained urgency, scientists and policymakers say, as the world moves toward regional, national and international agreements to limit greenhouse gases.
"If we expect to make treaties," said Steven Wofsy, a Harvard University professor of atmospheric and environmental science and another principal investigator, "those treaties have to be based on sound science. This slice of the atmosphere is going to help us understand that."
The effort is distinctly different from other efforts—such as the launch last week of a Japanese research satellite—to map carbon dioxide. Most measurements to date look solely at points on the surface. Satellite pictures can see broad swathes of the Earth but with very fuzzy resolution. This work, scientists said, examines nearly 100 different greenhouse gases in very fine detail at almost every altitude.
They have seen some "stunning" things: ground-level ozone, or smog, through the entire depth of the Northern Hemisphere at nearly triple the concentration observed in the Southern Hemisphere; a cloud of industrial pollutants sitting above the Arctic; a large mass of oxygen above the Southern Ocean.