Nature News

Greenhouse gases (C02 and methane) have reached record levels

Now that the data collected around the world in 2012 have been analyzed, the UN weather agency, the World Meteorological Organization, has found that the average global concentration of carbon dioxide continued its upward climb and reached 393.1 ppm. As reported in The Ottawa Citizen (Nov. 7, 2013), the increase in 2012, at 2.2 ppm, exceeded the annual average for the preceding decade (2.02 ppm). This uptick leads the UN panel to expect the atmospheric concentration to cross the 400 ppm threshold by 2016 (some places already have). Pre-industrial levels were around 280 ppm.

Carbon dioxide is thought to be responsible for 3/4 of global warming. Methane is another greenhouse gas that we've been pouring into the atmosphere, and its concentration reached 1819 ppm in 2012 — more than three times pre-industrial levels.

That the increase in CO2 concentrations should be accelerating when world industrial activity has been restrained by economic recession suggests to me that something new is happening. It may be that the little bit of warming we have already caused by burning fossil fuels has set in motion positive feedback loops in the natural world — permafrost may be thawing and peat oxidizing — and that the process is already beyond our control. This question is being examined locally, in the Mer Bleue bog in Ottawa's greenbelt. In July 2012, Dr. Elyn Humphreys explained to an OFNC group how, for 15 years, she and other researchers have been monitoring the carbon dioxide flux in this 10,000-year-old peatland. Their equipment is so sensitive that it can detect puffs of CO2-depleted air rising off the bog vegetation. So far, she said, Mer Bleu is still pulling CO2 out of the air and sequestering it as peat. — Rob Lee