Satellites can look at all of Earth all the time, and can give us lots of important information about our own planet. Satellites are used to forecast the weather, study changing land use, and show us how cities are growing. From space, we can also see many natural and man-made events, such as floods and forest fires, changes in ice cover, rising sea levels and air pollution.
ESA is now building a group of Earth Explorer satellites. Each of these complicated satellites is designed to study one topic in a lot of detail. Together, they will tell us more about the atmosphere, living organisms, rivers, oceans and ice sheets, as well as what’s happening inside Earth. The information they give us will also tell us more about how humans are affecting the natural environment.
ESA is also building a series of Earth Watch missions. Weather satellites carry instruments to look at clouds and winds, measure temperature and air pressure, and send back information about many other conditions on land, sea and in the air.
One example of this is MetOp – a weather satellite that looks at daily weather and the climate. It tells us about the atmosphere, clouds, temperature, humidity, ozone and winds.