Wood Romances

Note: 1/15/2024. Graphs are updated to include 2024 when available. You sometimes hear that, at least on certain time scales, CO2 and global temperature (GMST) don't correlate very well or even that the two go in opposite directions. The implication drawn from this is that CO2 can't be the primary driver of climate changes. What I want to show here is that this claim is categorically false. On virtually all time scales in the Phanerozoic, CO2 and GMST correlate very well, especially when taking into consideration that GMST correlates with the log of CO2.  The best way for me to demonstrate this point is to simply show the correlation. Where I can, I convert CO2 to forcings (using RF = 5.35*ln(CO2/280)) and and plot CO2 forcings on the x-axis and GMST on the y-axis. This gives us two advantages: first, it allows us to calculate the r^2 for that correlation, and second, the slope of the correlation gives us an indication of sensitivity - that is, the temperature response to chang...

In January, I blogged about a lecture I watched from Jessica Tierney, a geologist who has done some fascinating work in paleoclimate, in which she described the research behind a new paper that was at the time still undergoing peer review. You can watch the video and see my previous thoughts about this here . Ever since I watched this lecture, I have been anticipating the publication of the paper and hoping that the text wouldn't be behind a pay wall so I could learn more about what Tierney shared in her lecture. Well, late last week, both of my hopes became a reality. The paper is published and the full version is available. The lead author is Emily Judd[1], and this appears to be a remarkable paper. The tl;dr for this paper is that Emily Judd and her colleagues put together a data analysis (PhanDA) reconstruction of global temperatures and CO2 for the last 485 million years (most of the Phanerozoic), and they found that GMST varied greatly on geologic time scales, ranging from ...

My last post  was a bit of a rant. I apologize for that (sort of), though I get bombarded with these obviously erroneous graphs, and I wanted to put down in one place all the problems I have with that family of contrarian graphs. But it occurred to me today that it would be more helpful (and less of a rant) if I demonstrate how the data used in those graphs would look different if the problems I described were fixed. So to do this, I went on an internet search and found a wonderful set of data from a paper I described in an earlier post , Royer 2004. It's a spreadsheet with the data from the GEOCARB III model (which originates in Berner 2001) and global temperatures corrected from Vezier.[1] This only goes back 520 million years, but I found the full Berner CO2 data on another site.[2] The CO2 data is reported in RCO2, which is the ratio of CO2 at a time in the past and preindustrial CO2 (280 ppm). So I converted these values to a change in radiative forcing (RF) from preindustrial...

Reconstructed Temperatures (Top), Modeled CO2 (Bottom) and Glaciation (Blue) My interest in climate science came from my background in geology, which lead to an interest in paleoclimates, which then lead to better understanding more recent climate changes. I thought it might be interesting to share some of the more recent studies examining the correlation between CO2 and global temperature over the course of the 21st century so far. The tl;dr is simply this: there is a robust correlation between modeled and proxy evidence for CO2 and both reconstructed temperatures and evidence for glaciation across the Phanerozoic. In 2001, Robert Berner constructed a climate model to “predict” CO2 levels throughout the Phanerozoic.[1] In that paper, he also provided the proxy data for CO2 during the last 420 years or so. He was able to demonstrate that lower levels of CO2 correspond to periods of glaciation, and high CO2 levels correspond to periods with no glaciation. GEOCARBIII Climate Model CO2 Re...

One of the most interesting papers[1] I’ve seen in the last few years looks at future of climate forcing compared to the last 420 million years of geologic history. The study compiled CO2 proxy data for the last 420 million years from “1,241 independent estimates coming from five proxy methods and 112 published studies.” The resulting CO2 timeline is expressed both in terms of absolute concentrations and radiative forcing, accounting for both CO2 and the steady increase of solar output over time. The resulting timeline was then compared to the “representative concentration pathways” for future CO2 emissions. Under the “business as usual” RCP 8.5, “fossil fuel emissions suggest that atmospheric CO2 could peak in 2,250 AD at ∼2,000 p.p.m.” This would produce CO2 levels similar to the latter half of the Triassic (220-200 million years ago). However, given the increase in solar output, the radiative forcing this would produce would be similar to the early Eocene, likely exceeding the geolo...