Paleo Temperatures
Number of papers: 8
How Reliable Are Global Temperature Reconstructions of the Common Era? — Earth, 2022; Lüning & Lengsfeld
The authors compared seven prominent hemispheric and global temperature reconstructions for the past 2000 years, finding: “The discrepancies between the different T2k reconstructions directly translate into a major challenge with regards to the political interpretation of the climate change risk profile. As a rule of thumb, the larger/smaller the pre-industrial temperature changes, the higher/lower the natural contribution to the current warm period (CWP) will likely be, thus, reducing/increasing the CO2 climate sensitivity and the expected warming until 2100.”
Revisiting the Holocene global temperature conundrum — Nature, 2022; Kaufman & Broadman
The researchers show that the CMIP6 models can’t accurately predict the past. They say “A landmark reconstruction of GMST showed peak warmth during the mid-Holocene, when GMST reached about 0.8 °C higher than that of the preindustrial period. By contrast, early transient climate modeling showed that GMST was around −0.5 °C colder during the mid-Holocene compared with preindustrial [aka Little Ice Age] temperature, followed by continued warming.” This is significant, because the IPCC maintains that temperatures now are higher than they have ever been, yet there is plenty of evidence to show that temperatures were higher 6500 years ago than the IPCC claims. Javier Vinos explains that if the models are too hot now, that means they are too cold in the past, and that’s exactly what this paper shows. Andy May has a review.
Complex spatio-temporal structure of the Holocene Thermal Maximum — Nature Communications, 2022; Cartapanis et al.
This well written paper shows discrepancies among all the various proxy temperature datasets, implying that temperature reconstructions should be much more local and much less global. This has huge implications for climate models, which are based on the assumption that “forcing” happens globally. They show it doesn’t, calling into question the validity of models both for hindcasting and forecasting.
Exceptional warmth and climate instability occurred in the European Alps during the Last Interglacial period — Communications Earth & Environment, 2020; Wilcox et al.
“We find that temperatures were up to 4.3 °C warmer during the Last Interglacial period than in our present-day reference period 1971 to 1990. Climate instability, including an abrupt cooling event about 125,500 years ago, interrupted this thermal optimum but temperatures remained up to 2.0 °C warmer than the present day.”
Environments during the spread of anatomically modern humans across Northern Asia 50–10 cal kyr BP: What do we know and what would we like to know? — Quaternary International, 2021; Tarasov et al.
The authors find: “Contrary to the long-standing view of a generally colder-than-present last glacial climate, these proxy records reveal evidence that summers were warmer than today by several degrees Celsius, providing additional advantages for human activities.”
Paleo-Ecology of the Yedoma Ice Complex on Sobo-Sise Island (EasternLena Delta, Siberian Arctic — Frontiers in Earth Science, 2021; Wetterich et al.
Among many findings, the authors learn “July temperature reconstructions from the western part of the Yana-Indigirka lowland (east of the study area) reveal similar-to or warmer-than-today temperatures (by up to 4–4.5°C) and higher-than-today annual precipitation (by up to 50–100 mm) between about 39 and 31 cal kyr BP …”
Ötzi, 30 years on: A reappraisal of the depositional and post-depositional history of the find — The Holocene, 2022; Pilø et al.
This interesting paper tells the story of a preserved human mummy who lived 5,300 years ago in the Italian Alps. Researchers initially said he had been buried in ice for the entire 5,300 years, until “global warming” revealed the body in 1991. This paper challenges that story, saying “… it is likely that Ötzi was not permanently buried in ice immediately after his death, but that the gully where he lay was repeatedly exposed over the next 1500 years.”
Revised records of atmospheric trace gases CO2, CH4, N2O, and δ13C-CO2 over the last 2000 years from Law Dome, Antarctica — Earth System Science Data, 2019; Rubino et al.
Shows more precisely how CO2 and temperature have varied over the last 2000 years:
These are the latest and best figures for CO2 from 0AD to 1850 from Antarctic ice cores. What do they show? They show that CO2 rose during the Medieval warm period and fell during the Little Ice Age. This is Henry’s law in action. It tells us that not 100 percent of the post-industrial rise in CO2 can be attributed to man. Temperatures have been heading up naturally, and so has some amount of CO2. How much is a guess, but my guess is that around 80 percent is from human activities and 20 percent is natural.