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Atmospheric CO2 Levels Breaks 410 ppm. Highest in 800,000 Years.

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The amount of carbon dioxide in the atmosphere just hit its highest level in 800,000 years and scientists predict deadly consequences.

We have a pretty good idea of what Earth's atmosphere has looked like for the past 800,000 years.

Humans like us —Homo sapiens—evolved only about 200,000 years ago, but ice-core records reveal intricate details of our planet's history from long before humans existed. By drilling more than3 kilometers deep into the ice sheets over Greenland and Antarctica, scientists can see how temperature and atmospheric carbon-dioxide levels have changed since then.

From that record, we know the atmosphere and the air that we breathe has never had as much carbon dioxide in it as it does today.

For the first time in recorded history, the average monthly level of CO2 in the atmosphere exceeded 410 parts per million in April,according to observations at the Mauna Loa Observatory in Hawaii.

Breathing the air of a new world

For the 800,000 years for which we have records, average global CO2 levels fluctuated between about 170 ppm and 280 ppm. Once humans started to burn fossil fuels in the industrial era, things changed rapidly.

Only in the industrial era has the number risen above 300 ppm. The concentration first crept above400 ppm in 2013, and it continues to climb.

There's a debate among scientists about the last time CO2 levels were this high. It might have been during the Pliocene era, 2 million to 4.6 million years ago, whensea levels were 60 to 80 feet higherthan today. Or it may have beenin the Miocene, 10 million to 14 million years ago, when seas were more than 100 feet higher than now.

In our 800,000-year record, ittook about 1,000 yearsfor CO2 levels to increase by 35 ppm. We're currently averaging an increase of more than 2 ppm a year, meaning we could hit an average of 500 ppm within the next 45 years.