Current CO2 Levels Appeared Far Earlier Than Previously Thought, Study Claims

A recent extensive examination of how much carbon dioxide was in the air way back and how hot it was paints a worrisome picture of where our Earth’s weather might be going.

The new study looks at rock records from the last 66 million years, helping us see how today’s carbon dioxide levels fit into the really long-term view.

One important finding is that the last time we had as much carbon dioxide in the air as we do now because of humans was 14 million years ago – way longer than previously thought.

The study also says that the Earth’s weather over a really long time can be greatly affected by greenhouse gases, leading to big changes that could happen over thousands of years.

Sensitivity of the climate over long time scales

A group of more than 80 researchers from 16 countries worked together for seven years to put together this study. It was just published in the Science journal.

“We have long known that adding CO2 to our atmosphere raises the temperature,” said Bärbel Hönisch, a geochemist at Columbia University’s Lamont-Doherty Earth Observatory, who coordinated the consortium. “This study gives us a much more robust idea of how sensitive the climate is over long time scales.”

Most scientists think that when the amount of CO2 in the air doubles, it will make the Earth’s average temperature go up by 1.5 to 4.5 degrees Celsius (2.7 to 8.1 Fahrenheit) over a few decades to centuries.

But there’s a recent study that says the current agreement might be too low. This study suggests the warming could be between 3.6 to 6 degrees Celsius for each doubling of CO2.

No matter what, with the way things are going now, all the guesses tell us that the Earth is very close to, or even past, a 2-degree warming. Many scientists say we really need to avoid this if we can.

Historical trends of CO2 concentration over time

In the late 1700s, there were about 280 parts per million (ppm) of CO2 in the air. Now, it’s gone up to 420 ppm, which is about a 50% increase. If things keep going like they are, we might hit 600 ppm or more by the end of the century.

Right now, we’re already on the uncertain path of warming, with temperatures going up by about 1.2 degrees Celsius (2.2 degrees Fahrenheit) since the late 1800s, as reported by SciTechDaily.

To figure out what might happen in the future, scientists look at how temperatures matched up with CO2 levels in the past. They study things like air bubbles trapped in ice, ancient soils and ocean sediments, and the structure of old plant leaves.