Global warming gases hit record high

Greenhouse gases reached a record level in the Earth’s atmosphere last year, the UN weather agency announced today.

The global average concentrations in the atmosphere of carbon dioxide, or CO2, and nitrous oxide, or N2O, were higher than ever in measurements co-ordinated by the World Meteorological Organisation (WMO), said Geir Braathen, a climate specialist at the Geneva-based agency.

Methane, the third of the three important greenhouse gases, remained stable between 2005 and 2006, he said.

Mr Braathen said measurements show that CO2 is contributing more to global warming than previously.

“CO2 as a greenhouse gas is getting more and more important,” he said.

CO2 contributed 87% to the warming effect over the last decade, but in the last five years alone, its contribution was 91%, Mr Braathen said. “This shows that CO2 is gaining importance as a greenhouse gas,” Mr Braathen said.

The concentration of carbon dioxide in the atmosphere rose by about half a percent last year to reach 381.2 parts per million, according to the agency. Nitrous oxide totalled 320.1 parts per billion, which is a quarter percent higher than in 2005.

Mr Braathen said it appeared the upward trend will continue at least for the next few years.

WMO’s annual Greenhouse Gas Bulletin provides widely accepted worldwide data on the amount of heat-trapping greenhouse gases in the atmosphere.

Studies have shown that human-produced carbon dioxide emissions heat the earth’s surface and cause greater water evaporation. That leads to more water vapour in the air, which contributes to higher air temperatures. CO2, methane and N2O are the most common greenhouse gases after water vapour.

They are produced partially by natural sources, such as wetlands, and partially by human activities like agriculture or fuel combustion.

There is 36.1% more carbon dioxide in the atmosphere than there was in the late 18th century, primarily because of combustion of fossil fuels, the WMO bulletin said.

The WMO also concluded that “Greenhouse gases are major drivers of global warning and climate change.”

It has said power plants, cars, ships and planes are all contributing to the rise in carbon dioxide emissions.

WMO said it based its findings on readings from 44 countries that were collected in Japan.