Well, another analysis of existing data suggests there is nothing unusual about sharp warm periods in climatic history. One of the prime theorems of climate hysteria is that we are in a period of exceptional warming caused by human emissions of CO2. Even assuming there is some warming currently (a proposition which is dubious to due various measurement and analytic tricks and urban heat effects), it appears to be well within historical natural variation. The hysterics claim human activities have caused a rise of 1.1 degrees Centigrade in the industrial era. So some real climate scientists decided to look and see whether, even if such a rise was an accurate statement, was it really unusual during the historical climate. An analysis of an existing Antarctic ice core record going back 800,000 years found that it was not. In fact, there were many, many instances of a 1.1 degree rise over the course of 100 years in that record looking back at our current interglacial period, which has lasted about 20,000 years. In fact 16% of all 100 year periods had such a rise. Interestingly, in earlier periods such a rise was very unusual, but that was during a period when obviously humans weren’t buring fossil fuels. Go figure. (SCE Article)
The paper is rubbish. Land warms or cools more than the oceans and high latitudes warm or cool more than low latitudes. So the temperature changes at Vostok would be 2 to 3 times the global average change. So the authors should be looking for changes of perhaps 2.5-3.0 degress. There might be a few such changes at Vostock, but not more than a few. Those probably occurred during glacial termination when the global temperature was in fact changing rapidly. That tells us nothing about whether such a change is common during an interglacial.
the paper is not rubbish, not at all. Vostok is far inland and has stable temps over time, unlike the peninsula. Glacial termination would show far more extreme temps. And glacial termination lasts a few hundred years at most.
Greenland GISP2 Ice Core
https://www.reddit.com/r/climate/comments/51ils7/greenland_gisp2_ice_core_last_10000_years/
NEEM
https://www.nature.com/articles/s41597-021-00916-9
A few comments on Mike’s response.
First – ice cores are currently the highest resolution proxies available. That being said, they remain proxies and are relatively low resolution in comparison to current day modern instruments. Most other proxies, such as tree rings are very low resolution compared to modern day instruments. While Mike is correct that polar regions tend to have larger temp swings based on limited data, the resolution of the proxy data declines as the proxies get closer to the equator.
The second comment is the proxies are poorly reconciled against other contemperanious data. For example one study shows the maximum glacier extent for a glacier 250km from the viking greenland settlement was during the MWP. That is a serious conflict when one takes into account the crop species grown during the MWP requires at least 2c warmer climate than present day. Neither of those two temp reconstruction reconcile with other known facts, yet climate scientists seem to believe the validity of the reconstruction in spite of the conflicting evidence.
another example is the retreating of melting glaciers revealing tree stumps which were obviously growing 50-100km north of their present day range.
The region where the ice cores are drilled does not have the same variability in temperature that the Antarctic peninsula does, and that peninsula is the region that people use for temperatures that supposedly show an “amplified” response to whatever factors drive temperature. The critical point of the article is to examine rates of temperature change and see if there is anything unusual about the supposed global average temperature change of the last 100 years. There isn’t. And it isn’t just this study, I have in the last few weeks posted on several other studies using different methods and locations showing that temperatures warmed and cooled very rapidly many times in the past. The whole point of these studies is that the default assumption should be that whatever happens is natural variation and there is a high burden of proof to demonstrate that it is human-caused, especially when we are bankrupting ourselves to address a likely non-existent problem.
Kevin – I agree with you. As noted in my comments, the paleo community has done a poor job or reconciling conflicting proxy reconstructions with other known events as I mentioned above. The two I mentioned above are only a small sampling of individual proxies that conflict with other known data. Pages2k and MBH98 & 99 heavily discount law dome and dome c, which are relatively high resolution proxies which show an elevated mwp. Other Antarctica proxies with much lower resolution are overweight the higher resolution proxies because the dont show an elevated mwp. As other well informed scientists have noted, there is considerable corruption in the paleo community. There is some indication that the climate gate emails were released by Ken Briffa in his attempt to force some honesty among his peers.