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Greenhouse gases have reached their highest levels since pre-industrial times, meteorologists warned on Monday.

The World Meteorological Organization (WMO) announced that 2008 saw the largest increase in greenhouse gases since 1998.

"We want decisions to be based not on rumors but on facts, so here are the facts," said Michel Jarraud, the WMO Secretary General, referring to the United Nations Climate Change Conference in Copenhagen in December.

The WMO Greenhouse Gas Bulletin shows that as of 2008, ratios of carbon dioxide, methane and nitrous oxide increased by 38 percent, 157 percent and 19 percent, respectively, since pre-industrial times before 1750.

"What this increase means was that Kyoto was not enough," said Jarraud, "but without Kyoto, it would be even worse." The bulletin revealed that chlorofluorocarbons (CFCs) are decreasing in concentration, thanks to the Montreal Protocol on Substances that Deplete the Ozone Layer, which entered into force in 1989, though other halogenated gases are increasing rapidly.

"What I know is that we should not give up. We should make every effort to get the best possible agreement in Copenhagen. It is important to be determined. It is important to minimize the amount of climate change. The more we delay the decisions, the bigger the impact," said Jarraud.

The WMO, through its Global Atmosphere Watch (GAW) Program, coordinates observations of greenhouse gases in the atmosphere through a network of 200 stations in more than 50 countries. The WMO was established in 1950. It has 188 member countries and is headquartered in Geneva.