Wood Romances

The graph above (and similar versions of it) is circulating widely on social media and promoted as evidence that the Holocene Thermal Maximum (HTM) between 5000 and 10,000 years ago was warmer than today. The graph originates from Javier Vinós' self-published book. In the graph above the black "b" time series is reported to be variability of global temperatures since the beginning of the Holocene. This particular version also shows Marcott et al 2013 as the "a" time series and Earth's obliquity as the "c" time series. My interest here has to do with the data tampering Vinós used to generate the black "b" time series, so I'm going to refer to this as the "Vinós time series." The Vinós time series is fabricated by tampering with Marcott's proxy data. In his self-published book and various blogposts, he has told us how he fabricated it. To see how he did so, we must first look at a version of this graph in which the Vinós t...

A paper was published in 2013[1] that reconstructed intermediate water temperatures (IWT) for an area of Indonesian waters around the Makassar Straight and the Flores Sea. The study includes two reconstructions, one at 500 m depth and another at 600 m to 900 m depth in an effort to show how Pacific IWT ha sbeen affected by high latitude source waters. The reconstruction somewhat predictably found that during the HTM, average IWT in this area were warmer than in 1970. Given the misuse of this paper by contrarians (see below), I think it best to quote directly from the paper so you can see precisely what this paper is actually about. The early Holocene warmth and subsequent IWT cooling in Indonesia is likely related to temperature variability in the higher-latitude source waters. To assess the mechanisms that caused these hydrographic variations, we estimate down-core salinities and densities for the 500- and 600- to 650-m depths. A temperature-salinity-density plot suggests that althoug...

  Now that 2023 is in the books, it's pretty clear that all global temperature datasets will show 2023 to be the warmest year on record by a significant margin. And since 21st century has exceeded the warmest temperatures of the Holocene (the current interglacial), it's also fair to say that 2023 has likely been the warmest year at least since the last interglacial ended 125K years ago. I'm going to wait until all the major datasets are updated to 2023 before saying more about 2023. But already the dishonesty from contrarians is coming out to spin 2023 into something other than what it actually was. Patrick Moore's Dishonesty Patrick Moore posted a tweet with the above graph claiming that what I summarized about 2023 above is an "outright lie." His words: The claim is being made that “2023 was the hottest year in 125,000 years”. This is an outright lie. The Holocene Climatic Optimum from about 10,000-5,000 years ago, when the Sahara was green, was warmer than...

In previous posts in this series , I've tried summarize what I consider bad behavior among those debating climate change. So far I've discussing what I consider statistically unethical practices - using short-term trends, misusing scales, and using local instead of global data. Here I'd like to look how we make comparisons between types of data. In climate science, we need to deal with all sorts of different kinds of data. For global temperatures, I can think of at least 3 - proxies, the instrumental record (satellites, thermometers), and models (reanalysis, modeled projections, etc). It's perfectly fine to create graphs that include all of these kinds of data, but in doing so, we have to make sure that we are communicating honestly and making comparisons accurately. Proxy data has lower resolution and larger confidence intervals than the instrumental record, and modeled projections always depend in part on the assumed scenario, and confidence intervals for these projec...

In a previous post , I considered whether the global temperature reconstruction continues to be valuable after 1) newer studies have been published with fewer seasonal biases and 2) criticisms that portions of the reconstruction are not robust. I concluded that the reconstruction continues to be valuable both because it remains a "conservative" look at temperature variability during the Holocene and because criticisms about the robustness of the reconstruction turn out to be entirely unfounded. What I'd like to do now is consider what the reconstruction tells us about natural climate variability during the Holocene and how this should cause us to evaluate current warming. A casual look at the Marcott 2013[1] with the instrumental record is certainly alarming. Marcott's Holocene reconstruction shows relatively slow warming up until about 7000 years ago, then slow cooling into the the Little Ice Age. There's a "bump" in the graph associated with the Mediev...

This is part one of a two part series on Marcott 2013. You can read the second part here . In 2013, Shaun Marcott and his collaborators published a global temperature reconstruction covering basically the entire Holocene - the last 11,300 years.[1] It was a significant achievement, and so it seems it must be vehemently attacked. The paper is nearly 10 years old at this point, and it's been both replicated and improved upon by later studies.[2][3] Perhaps therefore it's not really necessary for me to defend a paper that has both already been successfully defended[4][5][6][7] and has been replicated by further studies which use both more extensive proxies[2] and reanalyses.[3] However, the aspects of climate science that I find most fascinating are paleoclimate studies, and I would like this blog to develop a more or less "complete" treatment of the major paleoclimate studies that impact our understanding of climate science today. Seasonal Biases Long before Marcott...