Keeping track of the Earth's carbon-cycle components

Sir

In a recent Editorial (Nature 460, 436; 2009), you call for improved Earth-monitoring tools to verify whether climate policies are effective. I am pleased to report that the global carbon-monitoring activities of the Group on Earth Observations (GEO) are well on the way to meeting your recommended course of action and should make a useful contribution to climate discussions in Copenhagen at the end of the year.

More than 130 governments and leading international organizations are collaborating through the GEO to establish a Global Earth Observation System of Systems by the year 2015. They are interlinking their respective Earth-monitoring systems and developing common technical standards to pool information effectively and to promote the free dissemination of data.

This expanding coalition is already transforming the ability of governments to manage their natural resources.

Our system for analysing the three components of the carbon cycle (atmosphere, land and ocean) aims to provide high-quality information on carbon dioxide and methane concentrations and on emission variations. Carbon tracking and carbon storage is being evaluated from atmospheric CO₂ observations, air–surface exchange flux networks, surface ocean CO₂ and related marine biochemistry observations, for example.

These coordinated data should help provide the monitoring, reporting and verification information that is likely to be required by future regulatory frameworks for the inclusion of forests in post-Kyoto climate agreements. They will build on the GEO's existing and planned efforts in forest monitoring. With collaboration from national governments, space agencies and relevant technical experts, a template should emerge for a reliable global carbon-monitoring system.

Close cooperation with the Committee on Earth Observation Satellites and with the GEO Carbon Community of Practice means that plans can be implemented for collecting space-based greenhouse-gas data, particularly those provided by Japan's GOSAT ('greenhouse gases observing satellite') mission and NASA's replacement Orbiting Carbon Observatory.

Understanding the ability of the carbon cycle to continue to act as a partial sink for fossil-fuel emissions is crucial to future carbon budgeting. The GEO's projects will enable participating governments to benefit from their investment in Earth observations and to provide essential environmental information to policy-makers.