Carbon dioxide levels hit record high: WMO

Carbon dioxide concentrations have reached a crucial level.

The World Meteorological Organization (WMO), in an annual accounting of greenhouse gas concentrations in the atmosphere, reported that average levels of carbon dioxide exceeded 400 parts per million in the early months of 2015, a rise of 43 percent over pre-industrial levels. The report was compiled data from 125 monitoring stations by the WMO’s Global Atmospheric Watch program.

Atmospheric carbon dioxide concentrations of 0.04 percent may not seem like much but it is enough to have already raised average global temperatures by a full degree Celsius, according to the U.K.'s Met Office, with more warming on the way as the greenhouse gas lingers invisibly in the atmosphere, trapping heat, or mixing into the ocean, rendering its waters more acidic.

If the levels stay where they are, it could cause extreme weather, hotter temperatures worldwide, rising sea levels, melting ice, and increased ocean acidity.

This year is expected to be the world's warmest year on record, in part because of the warming influence of a strong El Niño event in the Pacific Ocean, which is adding more warming on top of the long-term manmade trend from greenhouse gas emissions.

Methane increased by 9 parts per billion from 2013 to 2014, compared with an average annual increase of 4.7 ppb, the report said.

The WMO maintains the world’s biggest network of sensors detecting changes in the makeup of the Earth’s atmosphere.