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.