'2011 rewrote the record books'

John Vidal in the Guardian (UK) present a tart summary of the last 12 months: The year 2011 was another ecologically tumultuous year with greenhouse gases rise to record levels, Arctic sea ice nearly equalling 2007's record melt, and temperatures the 11th highest ever recorded. It was marked on the ground by unparalleled extremes of heat and cold in the US, droughts and heatwaves in Europe and Africa and record numbers of weather-related natural disasters.

In addition, 2011 saw the world population reach 7 billion, the second worst nuclear disaster and record investments in renewable energy.

The 41 sea, land and air indicators used by the US government's National Oceanic and Atmospheric Administration (NOAA) to measure sea and land temperatures showed unequivocally that the world continued to warm throughout 2011. In July, NOAA reported that the last 300 months had all been above average temperature and that the 13 warmest years had all occurred in the 15 years since 1997. 2011 was additionally remarkable, it said, because a "La Niña" event was taking place, a naturally occurring oceanic cooling phenomenon that would normally bring temperatures down.

...In September, Germany's University of Bremen reported that Arctic sea ice had hit a record low, based on data from a Japanese sensor on Nasa's Aqua satellite. Days later, the US National Snow and Ice Data Centre, using a different satellite data set, reported that ice coverage in 2011 was marginally greater, making 2011 the second-lowest on record.

Christophe Kinnard, of the Centre for Advanced Studies in Arid Zones in La Serena, Chile reported in November that both the duration and magnitude of the current decline in sea ice "seem to be unprecedented for the past 1,450 years. Everything is trending up – surface temperature, the atmosphere, and it seems also that the ocean is warming and there is more warm and saline water that makes it into the Arctic. The sea ice is eroded from below and melting from the top," said Kinnard....

Broken sea ice in front of Helsinki, Finland in winter. Gulf of Finland. Shot by Pöllö, Wikimedia Commons, under the Creative Commons Attribution 3.0 Unported license