Earth Just Recorded Its Highest Carbon Dioxide Level In 3 Million Years

A research station that has been sitting on a volcano since the 1950s just recorded the highest concentration of carbon dioxide in the atmosphere in more than 3 million years -- long before modern humans even existed.

The Mauna Loa Observatory has been continuously monitoring and collecting data related to atmospheric changes since the 1950s.

Over the weekend, the levels of carbon dioxide (CO2) in the atmosphere surpassed a concentration of 415 parts per million (PPM) for the first time in more than 3 million years.

To put this into perspective -- Homo Sapiens first emerged around 200,000 years ago. The industrial revolution that initiated this steep increase in atmospheric carbon began approximately 260 years ago.

The observatory is run by the Scripps Institution of Oceanography and supported by the U.S. Department of Energy, and recorded the world's first surpassing of 400PPM of CO2 in 2016.

Ralph Keeling, director of the Scripps Institution of Oceanography CO2 program, said the increase of CO2 that the observatory records is seen every year and "is just not sustainable in terms of energy use and in terms of what we are doing to the planet".

Why is this measurement so important? 

Charles David Keeling (Ralph's father) was a pioneer of CO2 measurement and set up the Mauna Loa Observatory in 1958.

Keeling established the observatory just as man-made carbon emissions began to skyrocket; approximately 5 billion tonnes of CO2 were released in 1950. Today, we see more than 35 billion annually.

Mauna Loa. Source: Getty.

The measure that Keeling devised is recognised for its superior accuracy to other measures of CO2 levels, such as analysing tree rings or ice cores.

The Keeling Curve is recognised as a cornerstone of modern climate science and relies on readings from an infrared gas analyser to perform continuous measurements of CO2 in the air.

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Beginning in 1958, Keeling's observatory has recorded an increase in CO2 levels for each succeeding year, with the data informing how the world now understands the consequences of greenhouse gas emission.

Crater at the base of Mauna Loa. Source: Getty.

So, what does any of this really mean? 

The last time the Earth witnessed an atmosphere with the same heat-trapping ability as it currently holds with modern levels of CO2, it was in a stage called the Pliocene era.

This was a geologic era between five million and three millions years ago.

In the Pliocene era, the planet experienced global average temperatures three to four degrees hotter than today's averages and the sea level was up to 40 metres higher than it is today.

Eric Holthaus, a meteorologist, commented on Twitter that "we don't know a planet like this."

Based on fossil evidence from the Pliocene, the world experienced frequent and intense El Niño cycles, forests grew in the Canadian Arctic, coral reefs suffered a major extinction and the poles were up to 10 degrees warmer than they are today.

However, scientists from the Scripps Institution of Oceanography have commented that the Earth might react even more dramatically to levels of CO2 in the modern atmosphere due to the steep rise in the amount of this gas.

Jeff Severinghaus, a geoscientist from the University of California, San Diego, said that our grandchildren "will inhabit a radically altered planet, as the ocean gradually warms up in response to the buildup of heat-trapping gases."