Wood Romances

I recently read a fascinating study looking to understand why the “Mid-Pleistocene Transition” (MPT) happened about 1 million years ago. The MPT refers to the change where the glacial-interglacial cycles of the Pleistocene (the last 2.6 million years) changed from cycles of ~41,000 years to ~100,000 years. Both periodicities are synced to Milankovitch Cycles. During the early Pleistocene, the periodicity matches cycles in the earth’s obliquity, but after the MPT the glacial-interglacial cycles began to track more closely with variations in the earth’s orbital eccentricity. So the big question has been why the change? A recent paper by Willeit published in Science Advances [1] examined this by producing a model that was able to reproduce the MPT. In fact it accurately reproduced the maximum extent of the ice sheets as well as extent of sea level rise. It made use of the carbon cycle, volcanic activity, and changes in regolith cover. The model results indicate that continents had built u...

From Garavaglia et al 2012 Sociologically speaking, Tony Heller is a fascinating person. I mean, he's ridiculous, but in debate groups, it's not uncommon to see people defending his claims despite incontrovertible evidence that he's wrong. Some of this may have to do with his rhetoric. He begins every video he makes informing you that he's the sole authority on climate, and in almost every video he at some point will refer to climate scientists as liars, frauds, and criminals. In a recent video, though, he decided to take this a step further and start mocking random people on Twitter for being sad about the retreat of mountain glaciers. This was based on a news story by CNN reporting that WWI artifacts were found in a cave in Northern Italy. Climate change has recently made it possible to enter that cave and discover these artifacts. Heller imagined that the reason why that cave was able to be used during WWI was because the was no ice there then. After WWI, we're t...

Baltimore's Inner Harbor It is well-documented that cities are significantly warmer than rural areas. This effect is commonly described as an urban heat island (UHI). Some argue that some (or all) of the increase in global temperatures can be explained by the effect of the UHI effect on global temperatures. It makes some intuitive sense that this might be the case, but let's consider some important lines of evidence that suggest otherwise. First, while urban areas are warmer than rural areas, urban areas are warming at about the same rate as rural areas, so temperature anomalies are not significantly affected by urban heat islands.[1] Second, there is a well-documented bias that can be added to the temperature record from urbanization. As a rural area becomes more urban, it will warm at a faster rate than cities and rural areas. An area that is rural in 1950 but urban in 2020 will become progressively hotter due to urbanization, and not changing climatic conditions. However, nu...

Little Big Econ State Forest One objection I frequently hear to climate science is that the human contribution to the increase in CO2 concentrations is small, so reducing our carbon emissions will have little to no effect on global temperatures. This claim is completely misguided, and calculations using estimates of human carbon emissions can settle this pretty quickly. The following calculations are through 2018, with CO2 levels at 410 ppm, about 130 ppm higher than pre-industrial 280 pm. We can provide a rough estimate of how much of the 410 ppm is human by looking at empirical data regarding anthropogenic CO2 emissions  and a couple conversion factors:[1] 3.67GtC = 1 GtCO2  1 ppm CO2 = 7.81 GtCO2. According to the global carbon budget through 2018, humans have emitted 441 GtC through fossil fuel use and 203 GtC through land use, for a total of 604 GtC anthropogenic emissions.[2] That translates to 2217 Gt CO2 emissions. About 50% of that amount stays in the atmosphere. So: ...

Tree Overhanging the Econ River, Little Big Econ State Forest, May 9, 2021 My interest in "wood romances" spans the gamut from nature photography to hiking, to conservation, to understanding the future impacts of climate change. I frequently participate in on-line discussions on these matters, and many of the same issues get recycled in numerous contexts. I've taken to addressing these in relatively short responses so that I don't have to rewrite the same arguments, evidence and calculations. Here is a basic calculation of equilibrium sensitivity (ECS) that I did recently. ECS is the amount of increase in global mean surface temperature (GMST) after reaching equilibrium with a doubling of CO2 concentrations. There are many ways to do this, and this is a simple energy balance equation that uses empirical data for various forcings to arrive at the estimate. This of course is not the end of discussion on the matter. Many scientific studies have been written estimating t...