BERLIN -- An international team of researchers set off Friday on the biggest and most complex expedition ever attempted in the central Arctic, a yearlong journey they hope will sharpen the scientific models that underpin human understanding of climate change.
The 140-million euro ($158 million) expedition into the ice will see 600 scientists from 19 countries, including Germany, the United States, Britain, France, Russia and China, work together in one of the most inhospitable regions of the planet.
"The Arctic is the epicenter of global climate change," expedition leader Markus Rex of Germany's Alfred Wegener Institute for Polar and Ocean Research said ahead of the launch. "At the same time, the Arctic is the region of the planet where we understand the climate system least."
Packed full of scientific equipment, the German icebreaker RV Polarstern left the port of Tromsoe in northern Norway accompanied by a Russian vessel, the Akademik Fedorov, to search for a suitably large floe on which to anchor.
As the days get shorter and the sea freezes around the vessel, crews will race to set up research stations on the ice, some many miles away. Then the Polarstern and the network of camps are set to slowly drift toward the North Pole, with rotating teams of dozens of scientists spending two months conducting research on the ice.
Stefanie Arndt, a sea ice physicist who has been preparing for the expedition for nine years, said darkness will be the biggest challenge.
"Everyone worries about the cold but the psychological aspect of not seeing anything and knowing there are polar bears out there is something that shouldn't be underestimated," she told The Associated Press in a telephone interview.
Scientists involved in the Multidisciplinary drifting Observatory for the Study of Arctic Climate, or MOSAiC for short, have undergone firearms training. The camp will be also be secured by a perimeter fence and fireworks to scare off prowling predators.
Arndt, who will join the mission in mid-February, said the unique advantage of MOSAiC compared with other expeditions is the fact that researchers will be able to observe processes in the Arctic across an entire seasonal cycle.
"What's particularly interesting is the transition from winter to spring," she said, a time when the ice is normally too thick for ships to reach the Central Arctic.
Recording changes in the density, size and type of snow will help scientists better understand the flows of energy in the Arctic.
"For example, how much light the snow reflects back into the atmosphere, how much it absorbs and how much light reaches the upper ocean," said Arndt. "This has big implications for the ecosystem."
Energy from light affects algae growth and ocean temperatures, which in turn influence how much sea ice melts from below.
Understanding these and other complex processes occurring in the Arctic is essential for the increasingly sophisticated computer models scientists use to predict weather and climate. Experts believe that any disruption to the Arctic's delicate cycle of freeze-and-thaw will be felt further south, though it's still not clear how.
"The Arctic is changing pretty dramatically right now and that's something we need to get into," said Matthew Shupe, an atmospheric scientist at the University of Colorado who will take part in the expedition.
Recent changes in the jet stream — a current of air that circles and insulates the Arctic like a giant thermos — have allowed warm, moist winds from low latitudes to move north. At the same time, chilly blasts of Arctic air — the dreaded polar vortices — have brought deep freeze conditions to the continental U.S. and Europe.
"A lot of this right now is a hot topic," said Shupe.
Concerns about global warming have spread far beyond the scientific community in recent years. The expedition starts on the same day as global climate protests and ahead of a U.N. climate summit in New York next week.
"We want to provide a robust scientific basis for the important political decisions that our societies now have to make to mitigate climate change," said Rex, the expedition head.
The cooperation between scientists from many different countries stands in contrast to the geostrategic jostling by international powers as the Arctic, with its untapped riches, begins to open up to exploration.
Anja Karliczek, the German minister for science, said that as a major industrial nation Germany needs to shoulder part of the responsibility for tackling climate change, and financing half of the expedition's costs was in the country's interests.
Unlike Russia, China and Sweden, which will also be sending icebreakers to supply the expedition, the United States won't be contributing a vessel.
"A U.S.-flagged ship would have been a nice addition to MOSAiC," said Shupe. "On the other hand I think that the U.S. is making extraordinary contributions," he said, citing scientific and financial support from American institutions such as the National Science Foundation, the Department of Energy, the National Oceanic and Atmospheric Administration, and NASA.
MOSAiC mission: https://www.mosaic-expedition.org/