GENEVA, Nov. 25 (Xinhua) -- Greenhouse gases in the atmosphere continued to increase in 2007, with concentrations of carbon dioxide reaching new record levels, the World Meteorological Organization (WMO) said on Tuesday.

    Latest numbers published in the WMO's 2007 Greenhouse Gas Bulletin show that carbon dioxide reached 383.1 parts per million (ppm), an increase of 0.5 percent from 2006.

    Concentrations of nitrous oxide also reached record highs in 2007, up 0.25 percent from the year before, while methane increased 0.34 percent, exceeding the highest value so far recorded in 2003.

    Using the NOAA Annual greenhouse gas index, the total warming effect of all long-lived greenhouse gases was calculated to have increased by 1.06 percent from the previous year and by 24.2 percent since 1990, WMO said in a statement.

    Human activities, such as fossil fuel burning and agriculture, are major emitters of the gases, which scientists widely recognize as drivers of global warming and climate change.

    After water vapor, the four most prevalent greenhouse gases in the atmosphere are carbon dioxide, methane, nitrous oxide and chloro fluoro carbons (CFC).

    According to WMO figures, the levels of CFCs continued to decrease slowly, which can be seen as a good message.

    This showed the continued success of the Montreal Protocol to reduce emissions of ozone-depleting substances, WMO said.