|
Announcing the GEO Carbon Community of Practice
By Roger Dargaville, University of Melbourne; Leonard Barrie, World Meteorological Organization; James Butler, US National Oceanographic and Aeronautics Administration; Philippe Ciais, CNRS/CEA; and Han Dolman, VU University Amsterdam
The GEO Carbon Community of Practice has been established as an open group of scientists, program managers, funding agencies and policy makers with an interest in observing and understanding the global carbon cycle. The group will discuss the way forward for the carbon observing system and facilitate communication between those making observations and those developing models for making sense of the carbon cycle’s complexity.
This newest Community of Practice is a continuation of the IGOS-P Carbon Theme, which covers the entire carbon cycle including atmosphere, terrestrial and ocean domains. It integrates the already significant coordination efforts of groups such as Global Atmospheric Watch (GAW), the International Ocean Carbon Coordination Project (IOCCP), FLUXNet, the Global Carbon Project (GCP), the Global Terrestrial Observing System (GTOS), CarboEurope, the Coordinated Action Carbon Observing System (COCOS), the Integrated Carbon Observation System (ICOS), the North American Carbon Program (NACP) and many others.
The Carbon Community of Practice serves the implementation needs of the strategies published in the IGOS-P Carbon Theme Report (2002) and the IGACO-GHG Atmospheric Chemistry Theme Report (2004). Since then the networks have expanded and the technology available has improved dramatically. The Community of Practice will therefore produce a new GEO Carbon Report during 2009 outlining how far we have come and what steps still need to be taken.
Measuring the carbon cycle
Measuring and understanding the global carbon cycle is of critical importance for predicting future levels of greenhouse gases in the atmosphere and for estimating spatial distributions of the net exchange of carbon between the atmosphere and the Earth’s surface. The oceans and continents have absorbed about half of the carbon that has been emitted into the atmosphere from burning fossil fuel, but the way in which this ratio will change in the future is not well understood. Factors such as the ‘CO2 fertilization effect’ and longer growing seasons due to warming could enhance the uptake, while increased soil respiration, changing fire regimes, drought, thawing permafrost, and warming oceans could either decrease the natural sink or increase sources, in some cases, dramatically.
Only through observing the reservoirs and understanding fluxes among the land, ocean and atmosphere can we fully determine the response of the carbon cycle to climate variability. As carbon dioxide and other greenhouse gases are distributed throughout the atmosphere, observations need to be three dimensional. Furthermore, observations and models must be integrated in order to optimize the full power of observations.
Atmospheric carbon observations include the in situ and total-column, surface-based observations, aircraft observations (from commercial platforms such as JAL and CARIBIC and routine dedicated flights such as NOAA) and satellite observations (SCIAMACHY, AIRS, GOSAT). The WMO-Global Atmosphere Watch is the international framework for coordinating atmospheric observations, calibration, data quality objectives, and data management to fulfill various requirements of users such as those of inversion models for carbon tracking.
Land-air exchange observations over forests, grasslands and crops are made through a network of flux towers (coordinated through FLUXNet). Forest inventories measure changes in stocks over timescales of decades. Future space missions may be able to measure terrestrial forest carbon by P-band active radar, and concentration profiles retrieved using active LIDAR. Measurements of in situ atmospheric, surface water pCO2 and deep-water inorganic and organic carbon are made by ships of opportunity and research ships (coordinated through IOCCP).
In addition to the observation strategies, the Carbon Community of Practice will discuss the way forward to improve the integration of the observations using sophisticated modeling techniques (i.e. Carbon Cycle Data Assimilation System (CCDAS), Global Earth System Monitoring (GEMS) and CarbonTracker). Data management and sharing policies will also be addressed. |
