The steady rise in atmospheric levels of the greenhouse gases blamed for climate change shows no signs of abating, a UN agency has announced.
Rising levels of greenhouse gases are blamed for climate change
The atmospheric concentration of carbon dioxide rose by about half a percent in 2005, the World Meteorological Organisation (WMO) said.
It said levels were likely to keep rising unless emissions of CO2, methane and nitrogen oxides were slashed.
The announcement comes on the eve of UN climate negotiations in Nairobi.
"There is no sign that N2O (nitrous oxide) and CO2 are starting to level off," Geir Braathen, a senior scientist at the WMO, told reporters.
"It looks like it will just continue like this for the foreseeable future."
Scientists say the accumulation of such gases - generated by burning fossil fuels such as coal, oil and gas - traps energy coming originally from the Sun, causing global temperatures to rise.
This is expected to lead to melting of polar ice caps and glaciers, rising sea levels and more extreme weather events such as storms and floods.
The WMO said concentrations of carbon dioxide (CO2) were measured at 379.1 parts per million (ppm), up 0.53% from 377.1 ppm in 2004.
Concentrations of nitrous oxide (N2O) reached 319.2 parts per billion (ppb) in 2005, an annual increase of 0.2%.
Levels of methane, another greenhouse gas, remained stable, it said.
The trend of growing emissions from industry, transport and power generation is set to continue despite international agreements on regulating them, the UN agency warned.
"To really make CO2 level off we will need more drastic measures than are in the Kyoto Protocol today," Geir Braathen explained.
"Every human being on this globe should think about how much CO2 he or she emits and try to do something about that."
The Kyoto Protocol sets limits for emissions of six greenhouse gases for the richer countries of the world which have ratified it. The period for which targets exist runs until 2012.
The US and Australia have rejected the compulsory cap. China has ratified the Protocol, but as a developing nation, it is not required to reduce its emissions - despite its booming economy.
A report by former World Bank economist Sir Nicholas Stern this week warned of severe problems if global warming was ignored.
Governments involved in the United Nations climate convention and the Kyoto Protocol are due to meet in Nairobi from Monday to examine their future path in combatting global warming.
The latest data were gathered from monitoring stations, ships and aircraft around the world and are published in the WMO's second annual Greenhouse Gas Bulletin.