A Slovenian adventurer specialising in extreme flights headed towards the North Pole on Monday in an ultra-light plane equipped to measure air pollution over a hot-spot for global warming.
The GreenLight WorldFlight-North Pole project is the first attempt to pilot a flyweight plane from Europe to North America via the North Pole and back.
"The Arctic is a very important indicator of weather changes and it is crucial to research those areas," Matevz Lenarcic told AFP ahead of the solo mission.
The 15,600-kilometre (9,700-mile) scheme was initiated last year after Lenarcic, 54, succeeded in circling the world in the same aircraft, a Pipistrel Virus SW914, which weighs just 290 kilogrammes (640 pounds) unladen.
"The main problem this time will be weather, it can be very unstable in Europe at this time of the year," Lenarcic said.
Another worry will be extremely low temperatures in the Arctic and low air density, whose impacts on the tiny aircraft's engine are unclear.
Lenarcic plans to fly over the North Pole, arrive in Canada and then cross the Atlantic on the return flight to Europe, in hops ranging from 1,100 to 3,100 kilometres over three to four weeks.
His first stop will be in Denmark followed by Norway and then Canada.
Lenarcic, an accomplished aerial photographer, will take pictures and measure levels of black carbon and light absorbing particles over the Arctic at a height of 3,000-4,000 metres (9,800-13,000 feet), an altitude rarely explored by scientists.
These particles -- mostly the product of burning coal and other fossil fuels -- absorb light from the Sun and thus play a role in the complex equation of global warming.
The Arctic is one of the most sensitive regions for climate change and a generator of weather patterns for the northern hemisphere. Temperatures there are rising two or three times higher than the global average, causing a massive shrinkage in sea ice during summer.
The project is backed by Slovenian manufacturer Pipistrel, which makes extremely low-weight planes for endurance flying.