Scientists are now seeing results from a new ally in the battle against climate change. Help from above, in the form of a satellite 800 kilometres above the Earth’s surface, is now guiding environmental research. From the rapidly disappearing snows of Kilimanjaro to thinning Arctic sea ice, the effects of anthropogenic climate change can all be viewed from above.
Using satellites to collect data is not a new idea, but the success of this latest innovation is pushing its scientific value higher and driving costs down. In the 1970s, the European Space Agency developed a meteorological observation program designed to collect weather data for forecasts all over the world. The success of this program and others throughout the 1980s led to the development of the ENVISAT satellite.
Dr. John Burrows of the University of Bremen, gave a series of lectures last week at the McLennan Physical Labs for the 2007 Noble Lecture Series, hosted by U of T’s atmospheric physics group at the department of physics. His Friday colloquium focused on the use of space-based remote sensing to track global air pollution. With public concern over climate change growing, Burrows explained the necessity of this research.
“Pollution has changed from being a local phenomenon. We are moving from a time of scepticism to one of belief.”
In collaboration with the European Space Agency, the ENVISAT satellite was launched in 2002. Weighing in at 8,200 kilograms and featuring 10 data-collecting instrument clusters, ENVISAT is one of the largest satellites ever launched. Scientists watched it take off from the launch pad aboard an ARIANE-5 rocket-a vehicle historically plagued by launch failures-and breathed a sigh of relief when all went well.
Burrows is one of the many scientists intimately concerned with ENVISAT’s success.
Aboard the satellite is a technology Burrows helped develop. SCHIAMACHY-Greek for “chasing shadows”-is the short name for the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography. It measures the reflection and scattering of sunlight through the atmosphere over a wide range of wavelengths, using these measurements to determine the composition of the atmosphere all over the world. Compounds such as the greenhouse gases carbon dioxide, methane, nitric oxide and sulphur dioxide can be accurately tracked, helping scientists refine the mathematical models that predict the effects of climate change.
The level of detail obtained by these space instruments is astounding: emissions from cargo ships trace oceanic shipping lanes in bold lines, and individual emissions sources, such as a single smelting plant, can be pinpointed.
“We can follow human behaviour from space and more or less pick up individual [industrial] plants,” Burrows said. “During the Iraq war, a sulphite plant was bombed. We saw plumes for days.”
Already, the data collected over the past five years indicates that China’s contribution to global air pollution is rapidly increasing. The instruments can also visualize slash-and-burn agriculture in the Amazon basin and pollution output from the developing world helping to demonstrate how they contribute to global warming.
Although the enormous amount of data collected by ENVISAT is proving useful in many ways, it is not without cost. The entire project cost two billion euros (around $3 billion Canadian) over 15 years, making the SCHIAMACHY instrument bundle relatively cheap-even with scientists like Burrows working for free.
“It costs [the same as] a cup of coffee per person in Europe per year. SCHIAMACHY cost 100 million euros and our instruments cost 100,000 euros-we worked for the pleasure of being scientists.”
Burrows insists that orbiting remote-sensing technology is a cost-effective strategy, and over time costs will likely drop, encouraging engineers and funding agencies to build similar devices to track our planet.
