Landmark carbon dioxide levels bad news for Arctic

The cold Arctic Ocean is absorbing more carbon dioxide than warmer waters further south. Photo: Thomas Nilsen

Levels of carbon dioxide in the atmosphere are poised to consistently climb above 400 parts per million for the first time in human history - a reality that has damning implications for the Arctic.

“It’s kind of a wakeup moment,” says Ralph Keeling, director of the Scripps Carbon Dioxide Program in California that recorded levels of carbon dioxide above 400 parts per million for the first time at the Mauna Loa Observatory in Hawaii earlier this month.

Keeling’s father began measuring levels of atmospheric carbon dioxide at the observatory in the 1950s when carbon dioxide levels hovered around 300 parts per million. But the amount of carbon dioxide has been increasing steadily since then.

“The trend is driven almost entirely by the burning of fossil fuels and rates of fuel production have only gone up in the last few decades so the growth rate of carbon dioxide continues to accelerate,” Keeling told the BarentsObserver.

The high carbon dioxide levels have significant implications for the environment. Because carbon dioxide is a greenhouse gas, more of it in the atmosphere means climate change will accelerate. The earth will become greener because more carbon dioxide causes plants to photosynthesize faster and the chemistry of the world’s oceans will change as higher volumes of carbon dioxide are absorbed in their waters, making them more acidic.

These changes will be particularly devastating in the far north where impacts of climate change are often amplified, Keeling says.

Ingunn Skjelvan, a scientist with the Bjerknes Center for Climate Research in Norway, says this is partly because the cold Arctic Ocean absorbs more carbon dioxide than warmer waters further south.

Though salt in the ocean forms a natural buffer system that normally regulates pH levels, this process is becoming less effective because warmer weather causes freshwater in the Arctic to melt and this is reducing the salinity of the ocean.

“The main problem is that we’ll most likely disturb the ecosystems in the ocean and that at the end will also have an effect on the people who get their food and income from the sea,” Skjelvan says.

Carbon dioxide levels at Mauna Loa are now falling slightly below 400 parts per million, which is in line with seasonal fluctuation. Keeling says concentrations of the gas are always highest in May and then start to fall in the spring when more plants emerge to take up carbon dioxide through photosynthesis.

But readings of 400 parts per million will return and will start to become more and more common.

“There’s an inevitability to continue the trend as long as we continue to depend on fossil fuels the way we do,” Keeling says.