We Are F%$#ed

For a while, I have been saying that climate scientists have been underestimating the severity of global warming.  (See here, here, here, and here)

Remember all those dire consequences for a 1.5°C (2.7°F) increase in temperatures globally?

Remember how the IPCC said that a doubling of  CO2 levels might result in a global temperature increase of 4.5°C? (8.1°F)

Well, a new study is suggesting that the impact of increasing CO2 is even greater than previously thought, and that a doubling of atmospheric CO2 levels might result in a 14°C (25°F) temperature increase.

That is real end of the world stuff:

Doubling the atmospheric CO2 levels could raise Earth’s average temperature by 7 to 14 degrees Celsius (13 to 25.2 degrees Fahrenheit), according to sediment analysis from the Pacific Ocean near California conducted by researchers from NIOZ and the Universities of Utrecht and Bristol.

The results were recently published in the journal Nature Communications

“The temperature rise we found is much larger than the 2.3 to 4.5 degrees Celsius (4.1 to 8.1 degrees Fahrenheit) that the UN climate panel, IPCC, has been estimating so far,” said the first author, Caitlyn Witkowski. 

45-year-old drill core

The researchers used a 45-year-old drill core extracted from the bottom of the Pacific Ocean. “I realized that this core is very attractive for researchers, because the ocean floor at that spot has had oxygen-free conditions for many millions of years,” said Professor Jaap Sinninghe Damsté, senior scientist at NIOZ and professor of organic geochemistry at Utrecht University. 

………

From this record, the researchers were able to extract an indication of the past seawater temperature and an indication of ancient atmospheric CO2 levels, using a new approach.

………

The researchers derived the temperature using a method developed 20 years ago at NIOZ, called the TEX86 method. “That method uses specific substances that are present in the membrane of archaea, a distinct class of microorganisms,” Damsté explains.

“Those archaea optimize the chemical composition of their membrane depending on the temperature of the water in the upper 200 meters of the ocean. Substances from that membrane can be found as molecular fossils in the ocean sediments, and analyzed to this day.”

………

Damsté: “A very small fraction of the carbon on Earth occurs in a ‘heavy form,’ 13C instead of the usual 12C. Algae have a clear preference for 12C. However: the lower the CO2 concentration in the water, the more algae will also use the rare 13C. Thus, the 13C content of these two substances is a measure of the CO₂ content of the ocean water. And that in turn, according to solubility laws, correlates with the CO₂ content of the atmosphere.”

Using this new method, it appears that the CO2 concentration dropped from about 650 parts per million, 15 million years back, to 280 just before the industrial revolution.

………

When the researchers plot the derived temperature and atmospheric CO2 levels of the past 15 million years against each other, they find a strong relationship. The average temperature 15 million years ago was over 18 degrees Celsius (64.4 degrees Fahrenheit): 4 degrees Celsius (7.2 degrees Fahrenheit) warmer than today and about the level that the UN Climate Panel, IPCC, predicts for the year 2100 in the most extreme scenario.

Fighting anthropogenic climate change cannot be about convincing emitters to reduce output through incentives, and not just because it has been repeatedly shown that carbon offsets are a scam.

It won't get us there.

Legal mandates with a probability of swift criminal enforcement is the only way to fix this.