Randolph E. Schmid, Associated Press Yahoo News 23 Apr 08;
Major greenhouse gases in the air are accumulating faster than in the past despite efforts to curtail their growth.
Carbon dioxide concentration in the air increased by 2.4 parts per million last year, the National Oceanic and Atmospheric Administration reported Wednesday, and methane concentrations also rose rapidly.
Concern has grown in recent years about these gases, with most atmospheric scientists concerned that the increasing accumulation is causing the earth's temperature to rise, potentially disrupting climate and changing patterns of rainfall, drought and other storms.
The Intergovernmental Panel on Climate Change has worked to detail the scientific bases of this problem and the Kyoto agreement sought to encourage countries to take steps to reduce their greenhouse emissions. Some countries, particularly in Europe, have taken steps to reduce emissions.
But carbon dioxide emissions, primarily from burning fossil fuels such as coal, oil and gas have continued to increase.
Since 2000, annual increases of two parts per million or more have been common, compared with 1.5 ppm per year in the 1980s and less than one ppm per year during the 1960s, NOAA's Earth System Research Laboratory said.
Global concentration of carbon dioxide is now nearly 385 parts per million. Preindustrial carbon dioxide levels hovered around 280 ppm until 1850. Human activities pushed those levels up to 380 ppm by early 2006.
Rapidly growing industrialization in Asia and rising wetland emissions in the Arctic and tropics are the most likely causes of the recent methane increase, said Ed Dlugokencky from NOAA's Earth System Research Laboratory.
Methane in the atmosphere rose by 27 million tons last year after nearly a decade with little or no increase, he said.
Methane is 25 times more potent as a greenhouse gas than carbon dioxide, but there's far less of it in the atmosphere. When related climate affects are taken into account, methane's overall climate impact is nearly half that of carbon dioxide.
CO2, methane up sharply in 2007
Deborah Zabarenko, Reuters 23 Apr 08;
WASHINGTON (Reuters) - The amount of two key greenhouse gases in Earth's atmosphere rose sharply in 2007, and carbon dioxide levels this year are literally off the chart, the U.S. government reported on Wednesday.
In its annual index of greenhouse gas emissions, the National Oceanic and Atmospheric Administration found atmospheric carbon dioxide, the primary driver of global climate change, rose by 0.6 percent, or 19 billion tons last year.
The amount of methane increased by 0.5 percent, or 27 million tons, after nearly a decade of little or no change, according preliminary figures to scientists at the government's Earth System Research Laboratory in Colorado.
Methane's greenhouse effect is 25 times more potent than carbon dioxide's, but there is far less of it in the atmosphere. Overall, methane has about half the climate impact of carbon dioxide.
The primary source of carbon dioxide is the burning of fossil fuels, which is increasing, with China now the world's biggest emitter, said Pieter Tans, who studies greenhouse gases at the laboratory. The United States is second.
The greenhouse gas index, based on data from 60 sites around the world, showed that that last year's carbon dioxide increase added 2.4 molecules to every million molecules of air, a measurement known as parts per million, or ppm.
OFF THE CHART
Carbon dioxide levels were about 270 ppm in the mid-18th century, before the wide use of fossil fuels that began with the Industrial Revolution. Last year's levels were near 390 ppm, and they have been rising more steeply over the last three decades, Tans said in a telephone interview.
"The average (annual rise) over the last five or six years has been 2 ppm and that is actually steeper than it has been in previous decades," he said. "This whole decade the rate of increase has accelerated, and we have a very clear candidate (for the cause) and that's emissions from burning fossil fuels."
The rise continued in 2008, according to a chart of global carbon dioxide emissions online here, which showed world emissions of this gas heading off the chart at over 386 ppm.
"It's gloomy," Tans said. "With carbon dioxide emissions, we're on the wrong track, it's obvious. And I'm also fully convinced that we're in actually quite a dangerous situation for climate."
The increase in methane emissions after years of little change may indicate that methane locked for thousands of years in frozen Arctic soil known as permafrost is being emitted into the atmosphere as the soil melts.
"What used to be in the deep freeze is now being taken out in the warming," Tans said.
It is also possible that the 2007 rise in methane emissions is due to some other cause. Methane emissions rose sharply between 1978 and 1998 and then leveled off.
(Editing by Cynthia Osterman)
