GENEVA Nov 20 Atmospheric volumes of greenhouse
gases blamed for climate change hit a new record in 2011, the
World Meteorological Organization (WMO) said in its annual
Greenhouse Gas Bulletin on Tuesday.
The volume of carbon dioxide, the primary greenhouse gas
emitted by human activities, grew at a similar rate to the
previous decade and reached 390.9 parts per million (ppm), 40
percent above the pre-industrial level, the survey said.
It has increased by an average of 2 ppm for the past 10
Fossil fuels are the primary source of about 375 billion
tonnes of carbon that has been released into the atmosphere
since the industrial era began in 1750, the WMO said.
WMO Secretary-General Michel Jarraud said the billions of
tonnes of extra carbon dioxide would stay in the atmosphere for
centuries, causing the planet to warm further.
"We have already seen that the oceans are becoming more
acidic as a result of the carbon dioxide uptake, with potential
repercussions for the underwater food chain and coral reefs," he
said in a statement.
Levels of methane, another long-lived greenhouse gas, have
risen steadily for the past three years after levelling off for
about seven years. The reasons for that evening out are unclear.
Growth in volumes of a third gas, nitrous oxide, quickened
in 2011. It has a long-term climate impact that is 298 times
greater than carbon dioxide.
The WMO, the United Nations' weather agency, said the three
gases, which are closely linked to human activities such as
fossil fuel use, deforestation and intensive agriculture, had
increased the warming effect on the climate by 30 percent
between 1990 and 2011.
The prevalence of several less abundant greenhouse gases was
also growing fast, it said.
Sulphur hexafluoride, used as an electrical insulator in
power distribution equipment, had doubled in volume since the
mid-1990s, while hydrochlorofluorocarbons (HCFCs) and
hydrofluorocarbons (HFCs) were growing at a rapid rate from a
But chlorofluorocarbons (CFCs) and most halons were
decreasing, it said.