How cold was the ice age? Researchers now know – but blame ‘carbon’

Posted: August 27, 2020 by oldbrew in Ice ages, research, Temperature
Tags: , ,

Ice core sample [image credit: Discovering Antarctica]


But they ignore the fact that historical changes in carbon dioxide levels always followed changes in temperatures, so could not be the cause of such changes. The article below asserts the opposite, and talks about ‘better understanding’ while promoting a greenhouse climate theory that says one minor trace gas is all that matters.
– – –
A University of Arizona-led team has nailed down the temperature of the last ice age—the Last Glacial Maximum of 20,000 years ago—to about 46 degrees Fahrenheit (7.8 C), says Phys.org.

Their findings allow climate scientists to better understand the relationship between today’s rising levels of atmospheric carbon dioxide—a major greenhouse gas—and average global temperature.

The Last Glacial Maximum, or LGM, was a frigid period when huge glaciers covered about half of North America, Europe and South America and many parts of Asia, while flora and fauna that were adapted to the cold thrived.

“We have a lot of data about this time period because it has been studied for so long,” said Jessica Tierney, associate professor in the UArizona Department of Geosciences. “But one question science has long wanted answers to is simple: How cold was the ice age?”

Tracking Temperature

Tierney is lead author of a paper published today in Nature that found that the average global temperature of the ice age was 6 degrees Celsius (11 F) cooler than today. For context, the average global temperature of the 20th century was 14 C (57 F).

“In your own personal experience that might not sound like a big difference, but, in fact, it’s a huge change,” Tierney said.

She and her team also created maps to illustrate how temperature differences varied in specific regions across the globe.

“In North America and Europe, the most northern parts were covered in ice and were extremely cold. Even here in Arizona, there was big cooling,” Tierney said. “But the biggest cooling was in high latitudes, such as the Arctic, where it was about 14 C (25 F) colder than today.”

Their findings fit with scientific understanding of how Earth’s poles react to temperature changes.

“Climate models predict that the high latitudes will get warmer faster than low latitudes,” Tierney said. “When you look at future projections, it gets really warm over the Arctic. That’s referred to as polar amplification. Similarly, during the LGM, we find the reverse pattern. Higher latitudes are just more sensitive to climate change and will remain so going forward.”

Counting Carbon

Knowing the temperature of the ice age matters because it is used to calculate climate sensitivity, meaning how much the global temperature shifts in response to atmospheric carbon.

Tierney and her team determined that for every doubling of atmospheric carbon, global temperature should increase by 3.4 C (6.1 F), which is in the middle of the range predicted by the latest generation of climate models (1.8 to 5.6 C).

Atmospheric carbon dioxide levels during the ice age were about 180 parts per million, which is very low. Before the Industrial Revolution, levels rose to about 280 parts per million, and today they’ve reached 415 parts per million.

Full article here.

Comments
  1. There is no valid global climate science, and no competent clmate scientists:

    The System is Broken (March 2013)

    It is most amusing that these “researchers” say the modern temperature over the 20th century was 14C. That is simply a rewriting of history to “save” the “global warming” incompetent science.

    The whole surface of the Earth was re-formed, as late as 20,000 to 10,000 BC. There have been no natural global ice ages; entire continents have been moved over the arctic regions. The general scientific paradigm, of undirected evolution of not only the life on Earth, but the Earth itself, has been disproven by my discovery and thorough verification of that global reformation, which is the single objective source of all of mankind’s “ancient mysteries”, and all of the religiously-held misunderstandings of the past, and present. There will be no valid progress in science until that originating world (and solar system) design is accepted by all, and the too-well loved current theories at the root of the earth and life sciences are gently laid aside and forgotten.

  2. …not BC…20,000 to 10,000 years ago.

  3. Phoenix44 says:

    It’s just bizarre. Why did CO2 rise if rising CO2 is necessary to increase the temperature and so end the Ice Age? Why did it fall if falling CO2 is necessary to have the Ice Age in the first place? They just leap into the middle and ignore how they got there. The total lack of context makes so many science papers look stupid these days.

  4. oldbrew says:

    The Vostok Ice Core and the 14,000 Year CO2 Time Lag
    Posted on June 14, 2017 by Euan Mearns

    Does change in temperature and ice cover cause CO2 to change or does changing CO2 cause temperature to change? The climate science community has adopted the latter into their narrative, where very weak orbital factors trigger the cycles that are then amplified by changing CO2 and methane. This post will demonstrate beyond reasonable doubt that this part of the climate science narrative is untenable and should be dropped.

    http://euanmearns.com/the-vostok-ice-core-and-the-14000-year-co2-time-lag/

    See e.g. Fig. 3 and commentary around it, in ‘Data’ section.
    – – –
    Warmer oceans release CO2 faster than thought
    EARTH 25 April 2011

    Rising temperatures make carbon dioxide leak from the oceans for two main reasons. First, melting sea ice increases the rate that the ocean mixes, which dredges up CO2-rich deep ocean waters. Second, “when you warm the ocean up, just like warming up a Coke bottle, it drives the gas out,” says van Ommen.

    Read more: https://www.newscientist.com/article/dn20413-warmer-oceans-release-co2-faster-than-thought/

  5. JB says:

    Last Vostok plot I looked at has the temp dropping 10ºC from present (down to -8º). Of course that does not represent global avg–which I don’t see how they can determine with any accuracy that long ago.

    “In North America and Europe, the most northern parts were covered in ice and were extremely cold.”
    That’s funny. How did the Wooley mammoth and other temperate zone flora and fauna get buried below the black mat across Canada and Alaska/Siberia ca 11KBCE, WHERE THERE WAS SUPPOSED TO BE GIANT ICE CAPS?

    My take on these press releases is the researchers are suffering from intellectual flatulation. Don’t believe any of it.

  6. cognog2 says:

    If, as they say, CO2 levels were around 180 ppm; then there would not have been any plantlife around of any significance.🤯 How on earth do these people get published?

  7. oldbrew says:

    Atmospheric carbon dioxide levels during the ice age were about 180 parts per million, which is very low. Before the Industrial Revolution, levels rose to about 280 parts per million

    So CO2 levels rose by over 50% before any serious coal burning by humans.

  8. Gamecock says:

    ‘Tierney is lead author of a paper published today in Nature that found that the average global temperature of the ice age was 6 degrees Celsius (11 F) cooler than today.’

    False precision fallacy. 6 degrees +/- 5 degrees.

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