The Mid-Cretaceous era was the heyday of the dinosaurs but was also the warmest period in the last 149 million years, with temperatures in the tropics as high as 35 degrees Celsius and sea levels 170 metres higher than today. Even during months of darkness, swampy temperate rain forests were able to grow close to the South Pole, revealing an even warmer climate than what had previously been expected. 

Artist’s impression. (Alfred-Wegener-Institut/James McKay/CC-BY-4.0)        Click to Enlarge

To get these conditions, scientists believe that 90 million years ago the Antarctic continent was covered with vibrant and dense vegetation and there were no land-ice masses on the scale of an ice sheet. The work also suggests

that the carbon dioxide (CO2) levels then were higher than expected during the mid-Cretaceous period, 115-80 million years ago, challenging  the previous climate models for that period.

“Before our study, the general assumption was that the global carbon dioxide concentration in the Cretaceous was roughly 1,000 parts per million (ppm),” according to geoscientist Torsten Bickert from the University of Bremen in Germany. “But in our model-based experiments, it took carbon dioxide concentration levels of up to 1,680 ppm to reach the average temperatures back then in the Antarctic.”

However, little was known about the environment south of the Antarctic Circle at this time. Now, researchers have discovered evidence of a temperate rain forest in the region, such as would be found in New Zealand today. This was despite a four-month polar night, meaning for a third of every year there was no life-giving sunlight at all.

Drill Site Click to enlarge

The evidence for the Antarctic forest comes from a core of sediment drilled into the seabed near the Pine Island and Thwaites glaciers in West Antarctica. One section of the core, that would have originally been deposited on land, caught the researchers’ attention with its strange colour. The presence of the forest suggests average temperatures would have made it unlikely there would be an ice cap at the South Pole at that time.

The team CT-scanned the section of the core and discovered a dense network of fossil roots, which was so well preserved that they could make out individual cell structures. The sample also contained countless traces of pollen and spores from plants, including the first remnants of flowering plants ever found at these high Antarctic latitudes.

To reconstruct the environment of this preserved forest, the team assessed the climatic conditions under which the plants’ modern descendants live, as well as analysing temperature and precipitation indicators within the sample. The team of British and German scientists examined forest soil from the Cretaceous period within 559 miles of the South Pole and analyzed the preserved roots, pollen and spores within the soil.

They found that the annual mean air temperature was roughly two degrees warmer than the mean temperature in Germany today. Average summer temperatures were around 19 degrees Celsius; water temperatures in the rivers and swamps reached up to 20 degrees; and the amount and intensity of rainfall in West Antarctica were similar to those in today’s Wales. The current warmth of the earth is not unprecedented, not just by this new ice core evidence of an ancient rain forest in the Antarctic but also the Medieval Warming Period which was two degrees warmer than the global temperature today.

The Little Ice Age (LIA), which occurred approximately 450 tears ago, and the Medieval Warm Period (MWP) were both discovered and proven by Ice Core evidence back before 1990, but despite all the evidence presented they were removed from all IPCC reports after Michael Mann submitted his hockey stick graph (tree ring proxy data) which showed the earth had been actually cooling for 1000 years. Fellow scientist Keith Briffa also submitted a graph which actually showed cooling after 1961 but was rejected because it didn’t fit the narrative. The  period known as the Medieval Climatic Optimum. China was, however, cold at this time (mainly in winter) but South Japan was warm (Yoshino, 1978). This period of widespread warmth is notable in that there is no evidence that it was accompanied by an increase of greenhouse gases.
Cooler episodes have been associated with glacial advances in alpine regions of the world, such neo-glacial’ episodes have been increasingly common in the last few thousand years.

Of particular interest is the most recent cold event, the Little Ice Age, which resulted in extensive glacial advances in almost all alpine regions of the world between 150 and 450 years ago (Grove, 1988) so that glaciers were more extensive 100-200 years ago than known early everywhere (Figure 7 2) Although not a period of continuously cold climate, the Little Ice Age was probably the coolest and most globally extensive cool period since the Younger Dryas


  1. Alan Sanderson says:

    I wrote to you last year about the late Keith Briffa. His tree ring proxy was more accurate than that of Michael Mann whose data was accepted only because it showed the globe had gradually cooled for up to a 1000 years and the current warming was unprecedented.
    This discovery of an ancient rain forest is a major blow to climate activists.

  2. John says:

    Scientist’s ice core evidence showing the little ice age and the medieval warming period has been removed. WHY?. They had to be otherwise the Hockey Stick would look ridiculous. Global temperatures plummeted prior to the little ice age while emissions fell.
    When will this silliness end?

  3. Francis Day says:

    The proposition that scientists have all got together as one to falsify temperature readings is a bit rich. The real issue is global temperatures measured by modeling is not accurate and there have been mistakes. However the Little Ice Age and the Medieval Warm period, included in the IPCC papers, have been withdrawn without explanation, which is a cause for concern.

  4. Trent Sanger says:

    Tree ring data sets will vary between one and other depending on the tree and what part of the world samples were taken. Some areas are warmer and drier others colder and wetter. The fact that Mann’s data is different to Briffa is no surprise that is why tree ring data is considered unreliable.
    Basically, older trees grow slower, and that mimics the temperature signal researchers like Mann look for. Unless you correct for this issue, you end up with a false temperature signal, like a hockey stick in modern times. Separating a valid temperature signal from the natural growth pattern of the tree becomes a larger challenge with this correction.
    Ice core evidence is far more reliable which is why it was included in the IPCC papers but later removed because it didn’t fit with the unprecedented warming theory.

  5. Dean W says:

    After several emails suggesting a review of the Mann’s tree ring data Briffa had finally lost patience: “I believe that the recent warmth was probably matched about a thousand years ago”. “I do not believe that global mean temperatures have simply cooled progressively over thousands of years as Mike’s (Michael Mann) appears to and I contend that there is strong evidence for major changes in climate over the Holocene”.

  6. Judith says:

    The atmospheric concentration of carbon dioxide is generally the same everywhere, but temperature changes are not the same everywhere. How do we explain that?

  7. Reed Walters says:

    Replacing coal fired power with nuclear would be a real worry for left wing climate activists, not due to safety concerns but because it would result in almost zero emissions compared to that generated in the process of manufacturing, installation, maintenance and replacement of wind and solar power infrastructure. This could mean the end of the gravy train and the global warming swindle…that is their concern.The real problems are pollution and overpopulation.

Leave a Reply

Your email address will not be published. Required fields are marked *