Heat-trapping greenhouse gases in the atmosphere reached a record high in 2005, the United Nations' weather agency said Friday.
Measurements coordinated by the World Meteorological Organization indicate that the global average concentrations of carbon dioxide and nitrous oxide will increase this year too, said Geir Braathen, a climate specialist at the Geneva-based agency.
The concentration of carbon dioxide rose about 0.5% last year, to 379.1 parts per million. Nitrous oxide totaled 319.2 parts per billion, 0.19% higher than in 2004.
Levels of methane, another greenhouse gas, have remained stable since last year.