The laws of physics and chemistry are not negotiable”
Michel Jarraud World Meteorological Organization
Carbon dioxide is the most important of the gases that they track, but only
about half of the CO2 that's emitted by human activities remains in the
atmosphere, with the rest being absorbed by the plants, trees, the land and
the oceans.
Upsetting the balance
Since 1750, global average levels of CO2 in the atmosphere have increased
to 141% of the pre-industrial concentration of 278 parts per million (ppm).
According to the WMO there were 393.1ppm of carbon dioxide in the
atmosphere in 2012, an increase of 2.2ppm over 2011.
This was above the yearly average of 2.02ppm over the past decade.
"The observations highlight yet again how heat-trapping gases from human
activities have upset the natural balance of our atmosphere and are a major
contribution to climate change," said WMO Secretary-General Michel Jarraud.
"It is a worry. The more we delay action the bigger the risk we cannot stay
under the 2 degree Celsius limit that countries have agreed," he said.
While the daily measurement of carbon dioxide in the
atmosphere<http://www.bbc.co.uk/news/science-environment-22486153>exceeded
the symbolic 400ppm mark in May this year, according to the WMO
the global annual average CO2 concentration will cross this point in 2015
or 2016.
Levels of methane also reached record highs in 2012 of 1,819 parts per
billion. Concentrations have been increasing since 2007 after a period when
they appeared to be levelling off.
Methane concentrations from landfill sites and many other sources
including farming have risen again
The WMO report says that it is not yet possible to attribute the methane
increase to either human activities like cattle breeding and landfills or
natural sources such as wetlands.
They believe that the rising emissions come from the tropical and
mid-latitude northern hemisphere and not from the Arctic, where methane
from the melting of permafrost and hydrates has long been a concern.
Emissions of nitrous oxide have also grown, with the atmospheric
concentration in 2012 at 325.1 parts per billion, 120% above pre-industrial
levels.
Nitrous oxide gas, although its concentrations are tiny compared to CO2, is
298 times more warming and also plays a role in the destruction of the
ozone layer.
Recent research indicates that the rate of increase in emissions might be
slowing down <http://www.bbc.co.uk/news/science-environment-24742770>, but
the gases can continue to concentrate in the atmosphere and exert a climate
influence for hundreds if not thousands of years.
Scientists believe that the new data indicates that global warming will be
back with a vengeance, after a slowdown in the rate of temperature
increases<http://www.bbc.co.uk/news/science-environment-22567023>over
the past 14 years.
"The laws of physics and chemistry are not negotiable," said Michel Jarraud.
"Greenhouse gases are what they are, the laws of physics show they can only
contribute to warming the system, but parts of this heat may go in
different places like the oceans for some periods of time," he said.
This view was echoed by Prof Piers Forster from the University of Leeds.
"For the past decade or so the oceans have been sucking up this extra heat,
meaning that surface temperatures have only increased slowly.
"Don't expect this state of affairs to continue though, the extra heat will
eventually come out and bite us, so expect strong warming over the coming
decades."