GENEVA, Switzerland, November 8, 2013 (ENS) – The concentrations of greenhouse gases in the atmosphere reached a new record high in 2012, “continuing an upward and accelerating trend which is driving climate change and will shape the future of our planet for hundreds and thousands of years,” the World Meteorological Organization is warning.
A specialized agency of the United Nations, the the World Meteorological Organization, WMO, has a membership of 191 countries and territories that contribute and share scientific observations.
The WMO’s annual Greenhouse Gas Bulletin was released Tuesday, just ahead of the year’s most important climate negotiations, due to open in Warsaw, Poland on November 11.
The newly issued Bulletin shows that between 1990 and 2012 there was a 32 percent increase in the warming effect on Earth’s climate because of carbon dioxide, CO2, and other heat-trapping long-lived gases such as methane and nitrous oxide.
CO2, mainly from fossil fuel-related emissions, accounted for 80 percent of this increase.
The atmospheric increase of CO2 from 2011 to 2012 was higher than its average growth rate over the past 10 years, according to the Greenhouse Gas Bulletin, which reports on atmospheric concentrations – and not emissions – of greenhouse gases.
Emissions are what goes into the atmosphere. Concentrations are what remains in the atmosphere after the complex system of interactions between the atmosphere, biosphere and the oceans.
Fifty countries contributed data for the WMO Greenhouse Gas Bulletin. Measurement data are reported by participating countries and archived and distributed by the World Data Centre for Greenhouse Gases at the Japan Meteorological Agency.
“The observations from WMO’s extensive Global Atmosphere Watch network 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.
“The Intergovernmental Panel on Climate Change, IPCC, in its recent 5th Assessment Report stressed that atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years,” he warned.
“As a result of this, our climate is changing, our weather is more extreme, ice sheets and glaciers are melting and sea levels are rising,” warned Jarraud.
Since the start of the industrial era in 1750, the global average concentration of CO2 in the atmosphere has increased by 41 percent, methane by 160 percent and nitrous oxide by 20 percent, the Greenhouse Gas Bulletin shows.
What is happening in the atmosphere is one part of a much wider picture, says the WMO. Only about half of the CO2 emitted by human activities remains in the atmosphere, with the rest being absorbed in the biosphere and in the oceans.
“According to the IPCC, if we continue with business as usual, global average temperatures may be 4.6 degrees higher by the end of the century than pre-industrial levels – and even higher in some parts of the world,” Jarraud said. “This would have devastating consequences.”
“Limiting climate change will require large and sustained reductions of greenhouse gas emissions. We need to act now, otherwise we will jeopardize the future of our children, grandchildren and many future generations,” said Jarraud. “Time is not on our side.”
Top UN climate change official Christiana Figueres said the Warsaw meeting of nations that are Parties to the UN Framework Convention on Climate Change must advance international climate action towards a new global, legally binding agreement to limit the emission of greenhouse gases that would take effect by 2020.
“We approach the meeting in Warsaw at a pivotal moment in the international process to address climate change,” said Figueres.
“We still have time and the means to limit warming to the internationally agreed two degrees Celsius target. But to meet this international commitment, we must respond to what science is telling us,” she said. “We need to urgently harness all existing momentum and use all the tools we have at our disposal to shift to low-carbon and build resilience to climate change.”
World governments have agreed to limit warming to two degrees Celsius above the planetary temperature at the Industrial Revolution in the 1700s.
Carbon dioxide is the single most important greenhouse gas emitted by human activities such as fossil fuel burning and deforestation.
Globally, according to WMO’s Greenhouse Gas Bulletin, the amount of CO2 in the atmosphere reached 393.1 parts per million in 2012, or 141 percent of the pre-industrial level of 278 parts per million.
The amount of CO2 in the atmosphere increased 2.2 parts per million from 2011 to 2012, which is above the average 2.02 parts per million per year for the past 10 years, showing an accelerating trend.
Monthly observed concentrations of CO2 in the atmosphere exceeded the symbolic 400 parts per million threshhold at several Global Atmosphere Watch stations in the Arctic during 2012.
During 2013 hourly and daily concentrations passed this threshold in other parts of the world, including at Mauna Loa, Hawaii, the oldest continuous atmospheric measurement station in the world which is widely regarded as a benchmark site in the Global Atmosphere Watch.
The WMO says concentrations of CO2 in the atmosphere are subject to seasonal and regional fluctuations. At the current rate of increase, the global annual average CO2 concentration is set to cross the 400 parts per million threshold in 2015 or 2016.
CO2 lingers in the atmosphere for hundreds if not thousands of years and so will determine global mean surface warming by the late 21st century and beyond. Most aspects of climate change will persist for centuries even if emissions of CO2 are stopped immediately.
Methane is the second most important long-lived greenhouse gas. About 40 percent of methane is emitted into the atmosphere by natural sources such as wetlands, and about 60 percent comes from human activities like cattle breeding, rice agriculture, fossil fuel exploitation, landfills and biomass burning, according to the WMO.
Atmospheric methane reached a new high of about 1819 parts per billion (ppb) in 2012, or 260 percent of the pre-industrial level, due to increased emissions from human sources. Since 2007, atmospheric methane has been increasing again after a temporary levelling-off period.
In a special section on methane, the WMO Greenhouse Gas Bulletin said that there has not yet been a measurable increase in Arctic methane due to melting of the permafrost and hydrates.
Instead, the Bulletin attributed the increase in global average methane levels to increased emissions in the tropical and mid-latitude Northern Hemisphere.
Attribution of this increase to human-influenced or natural sources requires better coverage and more sophisticated observations in the atmosphere which are currently not available, the WMO said.
Nitrous oxide is emitted into the atmosphere from both natural and human sources. Natural sources account for about 60 percent of nitrous oxide emissions and human sources account for the rest. This greenhouse gas is emitted by oceans, soil, biomass burning, fertilizer use, and industrial processes.
The atmospheric concentration of nitrous oxide in 2012 was about 325.1 parts per billion, which is 0.9 parts per billion above the previous year and 120 percent of the pre-industrial level.
The impact of nitrous oxide on the climate, over a 100-year period, is 298 times greater than equal emissions of carbon dioxide, says the WMO.
This gas also plays an important role in the destruction of the stratospheric ozone layer which protects us from the harmful ultraviolet rays of the sun.
The total radiative forcing by all long-lived greenhouse gases in 2012 corresponds to equivalent CO2 concentration of 475.6 parts per million, compared to 473.0 parts per million in 2011.
Other long-lived greenhouse gases include: ozone-depleting chlorofluorocarbons (CFCs), as well as hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) which are increasing at relatively rapid rates.
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