Carbon dioxide levels in the atmosphere are now at the highest level they’ve been since the Pilocene Era, 3 million years ago, when giant camels roamed arid land above the Arctic Circle. According to a new National Oceanic and Atmospheric Administration (NOAA) report, in 2018, the global average carbon dioxide amount reached a record high of 407.4 parts per million (ppm).
NOAA points a finger directly at humans, noting that the atmospheric carbon dioxide has increased about 100 times faster annually over the past 60 years than from previous natural increases. “Carbon dioxide concentrations are rising mostly because of the fossil fuels that people are burning for energy,” the report said. “Fossil fuels like coal and oil contain carbon that plants pulled out of the atmosphere through photosynthesis over the span of many millions of years; we are returning that carbon to the atmosphere in just a few hundred years.”
Globally, atmospheric carbon dioxide increased about 0.6 ppm per year in the 1960s. In the last 10 years, this figure has been about 2.3 ppm per year, the study said.
Carbon dioxide absorbs and radiates heat more than other major atmospheric components, such as oxygen or nitrogen. The NOAA report likens greenhouse gases to bricks in a fireplace that continue to release heat after the fire goes out. This warming effect is necessary to keep Earth’s temperature above freezing — up to a point. But once the level gets out of balance, these greenhouse gas “bricks” trap too much heat and make the Earth’s average temperature continue to rise.
Carbon dioxide also dissolves into the oceans, where it reacts with water molecules to produce carbonic acid and lower pH levels. Since the Industrial Revolution began in the late 18th century, the ocean’s pH has dropped significantly, interfering with marine animals’ ability to fortify their shells and skeletons by extracting calcium from the water.
“For millions of years, we haven’t had an atmosphere with a chemical composition as it is right now,” Martin Siegert, co-director of the Grantham Institute at Imperial College London, told NBC News. “We’ve done in a little more than 50 years what the Earth naturally took 10,000 years to do.”
Image via Marcin Jozwiak