After the burning of fossil fuels, logging is the largest source of carbon dioxide emission into the atmosphere and as such, it is a driving factor behind climate change. Carbon dioxide is released primarily when wood is burned. However, this also occurs during the decaying process of logs, branches and roots. Estimates indicate that logging is the reason behind 10-30 percent of the total amount of carbon dioxide that is released into the atmosphere. The wide range of the estimate is due to uncertainty about just how much biomass exists in the world's forests and the extent of forest destruction that is occurring.

This is why the European Space Agency, ESA, is working with a group of European researchers in order to be able to scientifically motivate how satellites can be used to make global forest surveys. Among other things, the goal is to be able to see developments in the area of forest destruction.

The project, called BIOMASS, relies on SAR (synthetic aperture radar) on the UHF bandwidth. This is a type of radar technology, which FOI has been involved in developing since the 1970s. It is, for example, used in the Swedish radar systems, CARABAS and LORA, in order to locate hidden objects in the terrain. Lars Ulander, FOI's research director for radar systems, is a member of the research group that is evaluating BIOMASS.

"Using a satellite to make global forest surveys has been a topic of discussion for many years. But, now the need has increased due to the fact that logging is the largest uncertainty factor in the carbon budget, not least because in many

countries that have tropical rainforests, there are no controls on logging activities. A satellite enables us to establish the amount of biomass trapped in the world's forests, as well as the amount that is released due to logging. In this way, we can calculate the speed of climate change more reliably," he says.

The project began in 2005 following ESA's challenge to European researchers to come up with climate applications for satellites. Of the 22 suggestions that were submitted, three now remain for a final round of evaluations. Competitors to the BIOMASS project are a project to use satellites to measure snow and ice and a project aimed at measuring water vapor in the atmosphere. One of these projects will be implemented and the decision on which one will be made in 2011. Five years later, the satellite will be launched. The decision will be made by ESA. However, statements by the scientific group, Earth Science Advisory Committee, will carry a great deal of weight. Lars Ulander is convinced that BIOMASS will be the winner (he also points out that Chalmers and SLU in Umeå are participating in the preparatory work).

"We have the strongest scientific argument for why these global surveys must be made. We also have a concept based on existing technology, which makes the project less risky. A satellite mission costs a couple of billion kronor and when that much money is at stake, you want some assurances that things will work," says Ulander.