Weighing in at 35 tonnes and using 50 kilometres (31 miles) of cables, the supercomputer named "Blizzard" at the German Climate Research Centre in Hamburg is capable of 158 TeraFlops, or 158 trillion calculations, per second.
Scientists said that in addition to tracking reactions in the atmosphere and the oceans, the computer should be able to work out the influence of ice and plants on greenhouse gases and climate change.
"Blizzard" is "60 times faster than its predecessor and one of the world's largest supercomputers," the centre said in a statement. "The new supercomputer should be in a position to model even tornadoes and very small eddies."
The centre is already providing data being used at the UN climate conference in Copenhagen.