A satellite that will study how climate change affects the Earth's icecaps has been successfully launched by the European Space Agency (ESA) from the Baikonur Cosmodrome in Kazakhstan. The first CryoSat satellite was lost during a launch failure in 2005.

ESA scientists say CryoSat-2 will measure changes in the thickness of the vast ice sheets that cover Antarctica and Greenland as well as variations in the thickness of polar sea ice. The satellite is carrying a purpose-built, all-weather microwave radar altimeter capable of detecting changes in ice thickness to within one centimetre.

Over the last decade, there have been significant losses of floating summer sea ice in the Arctic and large banks of the ice on the Antarctic Peninsula have broken up. There is increasing evidence that global warming is to blame. However, much remains a mystery as scientists are dependent on information from submarines that happen to be passing. A US satellite gathering similar data is no longer functional.

"In the period between proposing CryoSat in 1999, the Arctic ice decline has become a fact, rather than the prediction," said Duncan Wingham, the project's lead scientist. Even a small melt from the huge frozen reservoirs in the Antarctic and Arctic could cause a rise in sea levels and threaten many coastal towns and cities.

"We know from our radar satellites that sea ice is diminishing, but there is still an urgent need to understand how the volume of ice is changing," says Volker Liebig, ESAs director of Earth Observation Programmes.

CryoSat-2 is the third of ESAs Earth Explorer missions studying study the effect of human activity on thee earth's natural processes. ESA launched the Gravity Field and Ocean Circulation Explorer launched in March 2009 and the Soil Moisture and Ocean Salinity satellite went into orbit in November 2009. All three are monitored from ESAs European Space Operations Centre in Darmstadt, Germany.