A 2021 study appearing in Nature Communications by Buentgen et al reports on the results of a double-blind experiment of 15 different groups that yielded 15 different Northern Hemisphere summer temperature reconstructions.
Each group used the same network of regional tree-ring width datasets. [bold, links added]
What’s fascinating is that all groups, though using the same data network, came up with a different result.
When it comes to deriving temperatures from tree rings, it has much to do with individual approach and interpretation. Sure we can follow the science, but whose results?
The 15 groups (referred to as R1–R15) were challenged with the same task of developing the most reliable NH summer temperature reconstruction for the Common Era from nine high-elevation/high-latitude TRW datasets (Fig. 1):
The 15 groups who contributed independently to this experiment all had experience in developing tree ring-based climate reconstructions.
But as the study describes, each group employed a distinct reconstruction approach. In summary, the results ranged by as much as 1°C.
How could the groups come up with different results?
The paper’s abstract summarizes:
“Differing in their mean, variance, amplitude, sensitivity, and persistence, the ensemble members demonstrate the influence of subjectivity in the reconstruction process. We therefore recommend the routine use of ensemble reconstruction approaches to provide a more consensual picture of past climate variability.”
Hat-tip: Klimaschau 108
Read more at No Tricks Zone
Tree Rings can prove that in the past there was periods of Warming and Cooling long before Fossil Fuels was being used widely and prove Global Warming/Climate Change is a Lie
This could be referred to as a “tree ring circus”.
Not mentioned in the article is in the early days of the global warming movement the Hockey Stick graph was presented a irrefutable evidence that we needed to take drastic action to reduce carbon dioxide emissions. This graph was based on tree ring data. However, with the Hockey Stick, I suspect there was a lot of creative interpretation.
I’ve been a tree professional for the last 40 years. I’m an agronomist, an arborist and have been raising orchards for that period of time. I know the fine points of plant biology down to the sub-cellular level and use this knowledge to help diagnose and treat diseases in trees for homeowners in my area. I can say with good authority that tree ring width does NOT correlate exclusively with ambient temperature of the growing season as the global warming tree-ring promoters would have us believe.
This should be obvious to even those who grow flowers in a home garden bed, for if there’s marginal irrigation, say from scant rainfall, and the temperature increases without an adequate, if not a corresponding increase in irrigation, the flowers in one’s garden will wilt for lack of water and the cells loose turgor. So an increase in temperature must be accompanied by a corresponding increase in rainfall otherwise growth will be inhibited and the rings will not be wider in warmer years.
Now the climate catastrophists have been telling us that with increases in global temperature the earth will become drier and droughts will be more and more common. If that will be the case then surely tree rings will decrease in width. So increases in global temperatures, combined with the decreases in rainfall that they have been predicting, should result in normal or narrower rings to be the certain result of global warming. Yet they claim that they see tree ring increases exclusively due to GW. That doesn’t make sense.
But unfortunately for their agenda, with rising CO2 levels all plants and trees become more water efficient and so require less water to put on the same amount of growth. So tree rings may increase in width simply because of the greater water efficiency because of increased CO2 – having little to nothing to do with increasing global temps.
The bottom line here is that tree growth and the width of rings is a multi-factor phenomena and it cannot be attributed to only one thing like, like ambient temperature. Those who want to use tree rings to push their climate agenda are ignorant of the several basic biological factors that promote plant growth. Either they show their ignorance of basic plant science that most gardeners take for granted or know intuitively, or their climate agenda overrides simple common sense.