The carbon cycle is a key component of the climate system because it determines the amount of carbon dioxide (CO2) and methane (CH4) that accumulates in the atmosphere. The atmospheric burden of CO2 and CH4 leads to an intensification of the Earth’s natural greenhouse effect. This causes a shift in the planetary heat balance and forces the global climate system to change in ways that are not well understood, not least because of the complex interactions and feedbacks involved.

The carbon cycle also responds to climate change, and understanding the ability of the carbon cycle to continue to act as a partial sink of fossil fuel emissions into the future will be a vital factor in determining the “allowable” fossil fuel emissions, while keeping atmospheric CO2 concentration below desired levels. A monitoring system thus also functions as a key part of a global environment early warning system. For these reasons understanding the global carbon cycle, and predicting its evolution under future climate scenarios is one of the biggest challenges facing environmental science today.

The development of a comprehensive (atmosphere, ocean, land) global carbon observation and analysis system is expected to provide critical support to monitoring based decision-making and related environmental treaty obligations, contributing to the achievement of the GEOSS 2015 climate target (GEOSS 2015 Strategic Targets).

The GEO 2012-2015 Work Plan include a specific task on Carbon dedicated to contribute to the achievement of the 2015 GEOSS climate strategic target, namely the CL-02-C1: Integrated Global Carbon Observation and Analysis System. This task aims at developing a comprehensive global carbon observation system integrated across the atmosphere, land and ocean (including anthropogenic) domains, providing both improved estimates of carbon budget at different scales (from global to regional/national and reliable information and products for decision-makers, improving global observation networks of CO2, CH4, isotope ratios and exchange fluxes, developing an integrated carbon-cycle data assimilation system.