Daily film: Tree Stories: How #TreeRings Reveal Extreme Weather Cycles #FediTrees #FediForest #garden https://www.youtube.com/watch?v=xmZO7aRgcW4
posted by #bgfilmbot


Tree Story by Valerie Trouet, 2020
The History of the World Written in Rings
Children around the world know that to tell how old a tree is, you count its rings. Few people, however, know that research into tree rings has also made amazing contributions to our understanding of Earth's climate history and its influences on human civilization over the past 2,000 years.
I did something.
It's about the ColdBlob or SubPolarGyre or AMOC.
Specifically, about finding proxy locations on land for its annual evolution.
Taking SPG average sst in the months DJF and MAM, and computing also their year-on-year growth rate.
Then I computed the growth rate for DJF and MAM in all coordinates on land using Era5-Land 1951-2025.
And when the growthrate matches that of SPG within ±0.5 °C, it gets a ✅ .
6 ✅ per decade gets a 🔵 and counts toward selection.
Some more exclusion criteria applied, and I get a list of 315 locations on land for 🔵matching DJF growthrate, and a whopping additional 11,460 locations for MAM
In a 0.1x0.1 grid.
All DJF locations are in Papua. No proxies I know of have been recovered from Papua yet. I know all speleothems / stalagmites in caves🔴 , and all treerings ever analyzed🟢 , thanks to #NOAA .
But MAM °C has more locations. All of Indonesia basically is THE SPG in terms of growthrate. A few trees and speleothems match, one cave covers the whole #Holocene 🖖🏽
Large patches in Africa also match SPG in MAM. But only 2 short treering studies exist. No caves.
Middle and South America has plenty matching SPG MAM too, and a handful of trees and caves.
Yay.
#AMOC #climateChange #citizenscience #proxy #climateproxies #ColdBlob #SubPolarGyre
#Speleothem #treerings