Climate change is arguably the greatest challenge facing mankind in the twenty-first century. Its importance has been recognised in recent reports from the IPCC and from UNFCCC , and the overwhelming economic consequences are set out in the Stern Report.
Observations from space provide unique information which greatly assists the successful understanding and management of climate change. It is increasingly clear that these observations are critical, but as yet there is not, as in for example the case of meteorology, a co-ordinated sustained programme which will ensure they are available to all.
In addition, the nature of the problem requires that such data are adequately preserved over long periods of time, ensuring a reliable long term record. Over the course of the last few years a robust and formalised dialogue between the bodies with responsibility for the specification of climate observations and space agencies has led to a coherent set of requirement, agreed globally.
To respond to this need ESA has initiated a new programme, Global Monitoring of Essential Climate Variables (known for convenience as the ESA Climate Change Initiative) to provide an adequate, comprehensive, and timely response to the extremely challenging set of requirements for (highly stable) long-term satellite-based products for climate, that have been addressed to Space Agencies via the Global Climate Observing System (GCOS) and the Committee on Earth Observation Satellites (CEOS). It is exclusively concerned with addressing the explicit needs of UNFCCC.
The initiative will implement a programme of work which ensures that the responsibilities and capabilities of ESA member states in addressing issues of climate change can be undertaken on a scale commensurate with the problem.
It is based on the delivery of climate variables derived from satellite data sets (not just ESA but all sources via international collaboration) and includes all aspects of their availability including data acquisition, calibration and validation, long term algorithm maintenance, data curation and reprocessing as necessary, all within the context of an internationally agreed set of priorities.
The ESA programme will bring together European expertise covering the full range of scientific, technical and development specializations available within the European Earth Observation community, and will establish lasting and transparent access for global climate scientific and operational communities to its results.
The essential feature of the programme will be to implement a coherent and continuous suite of actions that encompasses all steps necessary for the systematic generation of relevant ECVs, and ensures their regular updating on timescales corresponding to the increasingly urgent needs of the international climate change community.
In this context it can be noted that the quadri-annual IPCC process, drawing primarily upon peer reviewed published results, implies much more frequent updating and reanalysis than would result from a 'best effort' approach.