An improved understanding of the Earth System – its weather, climate, oceans, land, geology, natural resources, ecosystems, and natural and human-induced hazards – is essential if we are to better predict, adapt and mitigate the expected global changes and their impacts on human civilisation.

Earth observation data and derived information are essential inputs in the development of this understanding. Earth observations provide the evidence necessary for informed decision-making – supporting the science which underpins strategies for global environmental decision-making – and for monitoring our progress on all geographical scales as we explore new development paths aimed at sustainable management of the planet.

The significance of Earth observations in our future decision-making processes is apparent in both the short term and long term.

— The long term: information extracted from long time series (several decades) of high quality observations is used in support of vital climate studies to observe and characterise the current climate, to detect climate change and to determine the rate of change. Furthermore, this information is analysed to assist in attributing the causes of change; identify any anthropogenic contribution to climate change; validate and calibrate climate models and assist in prediction of the future climate.

— The short term: information extracted from short time series (days or hours) of high quality observations is typically used to improve weather prediction by numerical forecast models, or to support operational applications (e.g. air quality, oceanography, land management, meteorology, disaster management). They also support land use and fresh water management and provide information for process studies to better understand physical processes in the Earth/atmosphere system.

Earth observation information will be required on all scales – from local to global. We can anticipate that it might be used by national and international authorities for decision-making to ensure sustainability, and also more locally as regions and industries compete for larger shares of smaller reserves of natural resources in order to support their growing populations and economic ambitions. Such information takes many forms, spanning data on population, demographics, economics and environmental indicators. Observations of planet Earth itself, and of human societies’ impact upon it, might be regarded as the most important context for societal decision-making.

Earth observing systems help to provide data in support of a wide range of information needs, including parameters which are central to:

— improved understanding: a multitude of global-scale observations contributing to research into Earth System processes;

— improved predictions, especially on a regional scale: global and regional observations over recent decades are essential to identify climate changes and to test and validate climate predictions in order to increase confidence in future climate projections that are fundamental to supporting adaptation planning;

— evidence: Earth observations support the formulation of authoritative scientific advice. This is vital for governments when deciding
whether to fund mitigation measures in response to climate change, how to react to impending crises in resource shortages, or whether to participate in agreements or Conventions which require costly changes in national consumption patterns;

— monitoring and compliance: we might expect to see increasing emphasis on international policy measures and treaties such as the Kyoto Protocol emerge in future. Earth observations will form an essential role in supporting such agreements, by verifying countries’ fulfilment of their treaty obligations vis-à-vis fossil fuel emissions or pollution dumping. The economic implications of such agreements can be enormous for countries, so highly visible and public measures to deter ‘cheating’ will be an important part of their success;

— management and mitigation: to support increased efficiency in basic resource provision for future generations while predicting and countering the worst effects of severe weather and natural disasters.

The beneficiaries of Earth observations are a broad range of users including: national, regional and local decision-makers; organisations responsible for the implementation of international Conventions and treaties; business, industry and service sectors; scientists and educators; and, ultimately, every inhabitant of planet Earth