Timely warning of natural and environmental disasters, accurate climate prediction and a detailed understanding, conservation and efficient management of scarce resources such as biomass, biosphere, mineral resources, water, and energy are essential requirements for sustainable economic development. Information about climate, climate change, weather, cryosphere, precipitation, pollution or disasters is a critically important everyday issue for the global community. Monitoring activities provide this information, which is required for the daily weather forecast and prediction, studies of climate change, for the protection of the environment, for economic development (transport, energy, agriculture, building construction, urban development, deployment of utilities, agriculture, security) and for safety of life and property. Earth observations are also used to obtain pertinent data regarding natural resources, this being particularly crucial for developing countries. It is important not to forget that this information is either based on measurements from, or gathered, provided and distributed by radiocommunication systems. Radio systems are fundamental to monitoring the climate and helping countries to mitigate and adapt to the effects of climate change and in addressing its major challenges. Any radio system that uses radio spectrum for its operation uses a limited, scarce resource. Availability of radio frequency bands free from harmful interference is a requirement for the development of all Earth observation systems.