Dramatic and unprecedented plumes of methane – a greenhouse gas 20 times more potent than carbon dioxide – have been seen bubbling to the surface of the Arctic Ocean by scientists undertaking an extensive survey of the region.

The scale and volume of the methane release has astonished the head of the Russian research team who has been surveying the seabed of the East Siberian Arctic Shelf off northern Russia for nearly 20 years.

We are right on the equator, and Speke, Moebius, Elena, Savoia and Moore, the five great glaciers of the the Rwenzori, the Mountains of the Moon, glint in the bright Ugandan sun. Usually lost in the mists that cloak these peaks up to 5,100 metres high, the glaciers are the only major ones left of the 43 that were mapped and named in 1906. Then, the ice covered 7.5 square kilometres, now it is thought to cover less than one.

U.S. sets record with a dozen billion-dollar weather disasters in one year

November and the September-November autumn season were warmer than average across the contiguous U.S., according to scientists at NOAA’s National Climatic Data Center (NCDC) in Asheville, N.C. Precipitation totals across the country were also above average during November, but near the long-term average for the autumn season.

A rise in the use of "ozone-friendly" HFCs has prompted experts to voice concerns that the potent greenhouse gases could be a problem in the future.

A UN report says that HFCs, many more times potent than CO2, could account for up to 20% of emissions and hamper efforts to curb climate change.

They are widely used in fridges and air conditioning, replacing CFCs and HCFCs that damage the Earth's ozone layer.

The findings were presented during a meeting on protecting the ozone layer.

Failures of urban planning are putting lives, infrastructure and businesses at risk as weather shocks – like the floods now surging through Bangkok – become more frequent as a result of climate change, urban planning and climate experts say.

But focusing on improving building codes, land use regulation, public health and sanitation, and disaster response measures could help reduce risks, said David Dodman, leader of the cities and climate team at the London-based International Institute for Environment and Development, which works on sustainable development issues.