Carbon dioxide and other greenhouse gases reached in 2004 the highest level ever. Carbon dioxide (CO2), methane and nitrous oxide all reached new records in 2004, according to officials of the World Meteorological Organization (WMO).

"Global observations coordinated by WMO show that levels of carbon dioxide, the most abundant greenhouse gas in the atmosphere, continue to increase steadily and show no signs of leveling off," said WMO Secretary-General Michel Jarraud. A great number of studies showed that the increased levels of carbon dioxide, methane and other gases in the atmosphere trap heat and raise the Earth's average temperature.

According to NASA, since 1800, 2005 had the highest annual average surface temperature worldwide. Scientists said that there is 35% more CO2 than in 1750, because the burning of fossil fuels. Methane also increased by 155% and nitrous oxides, also produced by natural sources, fertilizers, tree burning and industry, had an 18% increase.

Hans Verolme, director of climate change for the World Wildlife Fund in the United States, said that almost all scientists agree that these gases are linked to global warming. Electric power stations and cars are responsible for producing more than 40% of the emissions.

"The government ultimately did step in and say we will put a price on this pollution and we will leave it to the market to find the most efficient way to address it. People were saying it was too expensive, and it turned out to be not too expensive at all," Verolme added.

Global warming has been a difficult matter since the Bush administration rejecting the Kyoto protocol, which seeked to reduce emissions of greenhouse gases. Scientist worry that this overall warming will results in the melting of glaciers raising sea levels enough to damage many low-lying islands and cities around the world.