It appears these scientists were biased believing in anthropogenic forced climate! Indeed at least four of the authors of the research paper (i.e. Jesper Björklund, Kristina Seftigen, Marco Carrer, Georg von Arx) work for the Swiss Federal Institute for Forest Snow and Landscape Research WSL, Birmensdorf, Switzerland. Well on its website you find the second article listed below. As you can see from the title alone, these scientists are more like propagandists than scientists.
How accurate are actually tree-ring records? I am not an expert on this subject, but I suspect accuracy and reliability are not as high as advertised. It is fascinating that some trees can survive for thousands of years, but do their cells store accurate information about air temperatures. What is the variability given that each ring reflects an entire year.
The biggest problem with this study: They only used trees from a region in northern Europe. Maybe this region was not as warm as other parts of the world.
The tricks scientists play: They called it the Medieval Climate Anomaly (so was it cold or warm or what?), while the more proper name would be the Medieval Warm Period. Many people are probably not even aware that there was a Medieval Warm Period.
The study makes two bold claims (both of them are dubious):
- The Medieval Warming Period was not as warm as the current warming period
- Climate models are able to correctly reflect the Medieval Warming Period based on the new data
Just the fact that Vikings were able to settle on the island of Greenland for hundreds of years, while today's Greenland is still largely uninhabitable speaks volumes. Ever wondered why Greenland is called Greenland? The Vikings gave it that name for a reason.
Only 188 trees??? From the same region? The exact location of the trees appears to be withheld.
"... For their new time series, the researchers measured the cell walls of 50 million cells. These come from 188 living and dead Swedish and Finnish Scots pines (Pinus sylvestris), whose annual rings together cover a period of 1170 years ...
The result was clear: the temperatures of the models and the new time series align. ..."
From the abstract:
"Earth system models and various climate proxy sources indicate global warming is unprecedented during at least the Common Era. However, tree-ring proxies often estimate temperatures during the Medieval Climate Anomaly (950–1250 CE) that are similar to, or exceed, those recorded for the past century, in contrast to simulation experiments at regional scales. This not only calls into question the reliability of models and proxies but also contributes to uncertainty in future climate projections. Here we show that the current climate of the Fennoscandian Peninsula is substantially warmer than that of the medieval period. This highlights the dominant role of anthropogenic forcing in climate warming even at the regional scale, thereby reconciling inconsistencies between reconstructions and model simulations. We used an annually resolved 1,170-year-long tree-ring record that relies exclusively on tracheid anatomical measurements from Pinus sylvestris trees, providing high-fidelity measurements of instrumental temperature variability during the warm season. We therefore call for the construction of more such millennia-long records to further improve our understanding and reduce uncertainties around historical and future climate change at inter-regional and eventually global scales."
Tree-ring records solve Medieval warming climate mystery By scrutinizing millions of wood cells in ancient trees, scientists decode climate records, confirming the pivotal role of human-caused climate change.
