New figures released by two climate research bodies confirm that ‘greenhouse gases’ continue to build in Earth’s atmosphere and that average global temperatures made September 2013 the fourth warmest on record.
According to the World Meteorological Organisation’s (WMO) annual
greenhouse gas bulletin, published this month, the levels of gases in the
atmosphere that are driving climate change increased to a record high in 2012.
Atmospheric carbon dioxide (CO2) grew more rapidly in the year than its
average rise over the past decade - and concentrations of methane and nitrous
oxide also broke previous records.
The WMO has produced an annual greenhouse gas bulletin for the past nine
years and says the warming effect on our climate as a result of carbon dioxide
and other gases has increased by almost a third since 1990.
Carbon dioxide is the most important of the gases WMO tracks but only about
half of the CO2 that is emitted by human activities remains in the atmosphere,
with the rest being absorbed by the plants, trees, the land and the oceans.
Since the start of the industrial era in 1750,global average levels of
atmospheric CO2 have increased by 141 percent.
"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
"It is a worry - the more we delay action the bigger the risk we
cannot stay under the 2C limit that countries have agreed," he added.
While the daily measurement of carbon dioxide in the atmosphere exceeded
the symbolic 400ppm mark in May this year, the global annual average CO2 concentration
will cross this point in 2015 or 2016, says the WMO.
Levels of methane also reached record highs in 2012 maintaining an upward
trend since 2007 which has followed a period when they appeared to be levelling
Recent research indicates that the rate of increase in emissions might be
slowing down - but even so the gases can continue to concentrate in the
atmosphere and exert a climate influence for hundreds if not thousands of
Scientists suggest that the new data indicates that, after a slowdown in
the rate of temperature increases over the past 14 years, global warming is
returning with a vengeance.
"For the past decade or so the oceans have been sucking up this extra
heat, meaning that surface temperatures have only increased slowly," said
Prof Piers Forster of Leeds University.
"Don't expect this state of affairs to continue though - the extra
heat will eventually come out and bite us, so there will be strong warming over
the coming decades."
Should we be surprised? Not really. In September the UN's climate science
panel, the IPCC, said that atmospheric CO2 concentrations were at levels
‘unprecedented in at least the last 800,000 years’.
The last time so much greenhouse gas was in the air was several million
years ago, when the Arctic was ice-free, savannah spread across the Sahara
desert and sea levels were up to 40 metres higher than today.
But, as the WMO points out, the amount of CO2 in the atmosphere is only
half of the picture as much of the CO2 is being absorbed by the oceans.
Annual worldwide emissions from power plants, cars and other human
activities are currently several billion tonnes too high to keep global
temperature rises below 2C and show no sign of stopping.
Other figures released recently by NOAA’s National Climatic Data Center
under its ‘State of the Climate: Global Analysis for September 2013' show the
combined average temperature over global land and ocean surfaces for September
2013 tied with 2003 as the fourth highest for September on record - at 0.64C
above the 20th century average of 15.0C.
The global land surface temperature was 0.89C above the 20th century
average of 12.0C, marking the sixth warmest September on record.
For the ocean, the September global sea surface temperature was 0.54C above
the 20th Century average of 16.2C, tying with 2006 as the fourth highest for
September on record.
The combined global land and ocean average surface temperature for January
to September was 0.6C above the 20th century average of 14.1C, tying with 2003
as the sixth warmest such period on record.