Carbon dioxide hits 400 parts per million in Northern Hemisphere

Concentrations of carbon dioxide in the atmosphere have risen above 400 parts per million (ppm) in recording stations across the Arctic going as far south as Mongolia, reports the Associated Press. Such levels have not been seen in at least 800,000 years according to researchers. Carbon levels fluctuate depending on the region and the season and scientists say global concentrations will likely remain at around 395 ppm for the time being. Crossing the 400 ppm threshold "[is] a reminder to everybody that we haven't fixed this and we're still in trouble," Jim Butler, global monitoring director with the U.S.'s National Oceanic and Atmospheric Administration's (NOAA) Earth System Research Lab, told the AP. Prior to the Industrial Revolution, global carbon levels were stabilized at around 275-280 ppm. However, the burning of fossil fuels such as coal and gas, cement production, vast deforestation, industrialized agriculture, and other recent human impacts has resulted in carbon levels skyrocketing. Carbon can linger in the atmosphere for hundreds of years, before being sequestered into the oceans, depending on how much that ecosystem can hold. Despite nations worldwide pledging to tackle climate change, carbon emissions continue to rise worldwide. According to the International Energy Agency (IEA), carbon dioxide emissions rose 3.2 percent to a new record of 31.6 gigatons in 2011. Countries have pledged to keep global temperatures from rising beyond 2 degrees Celsius (3.6 degrees Fahrenheit), but scientists and experts warn that a lack of action is making this target increasingly unlikely. In fact, the IEA warns that the world is currently on track to hit 6 degrees Celsius (11 degrees Fahrenheit) by 2100, essentially leading to a climate catastrophe with temperatures rising further than they have been in 50 million years. "The news today, that some stations have measured concentrations above 400 ppm in the atmosphere, is further evidence that the world's political leaders—with a few honorable exceptions—are failing catastrophically to address the climate crisis," former Vice President and a vocal proponent of climate action Al Gore wrote to the AP. "History will not understand or forgive them." Climate change has already been linked to rising sea levels, melting glaciers, wildlife disruptions, vanishing Arctic sea ice, and a rise in extreme weather, including droughts and floods.