Residual Emissions
Residual emissions are carbon emissions that are difficult or impossible to (fully) eliminate due to technological or other limitations. These emissions are extremely important, because – given that we effectively cannot avoid them – they need to be compensated with various kinds of carbon removal technologies (mainly carbon capture and storage) to be able to reach net zero (or carbon-neutrality). Carbon removal is very energy intensive, however, and there are limits to how much carbon we can remove. Estimates of these limits vary, but the most optimistic ones are typically somewhere in the neighborhood of 25Gt/year, or roughly half our...
Predicting Global Warming for Dummies
Climate scientists use supercomputers and extremely complicated models to predict the future climate, but there is a shortcut that can be used to predict average global warming. The key to that shortcut is the following simple formula: $$ \Delta T_{anom.} = \frac {ECS \times ( C_{atm.} – 280 )} {280} \: – \: \psi,$$ in which \(\Delta T_{anom.}\) is the average temperature anomaly (or average global warming), \(ECS\) is “Equilibrium Climate Sensitivity”, \(C_{atm.}\) is atmospheric carbon (in ppm CO₂ equivalent), and \(\psi\) (from Greek ψῦχος, meaning “cold”) stands for various cooling effects. If you have the values of the variables...
Carbon-neutrality by 2050
(Originally published on December 15, 2020. First major revision on June 13, 2022. This is the second major version.) A few years after carbon-neutrality became an official goal in the Paris Agreement of 2015, one after the other, governments started to announce that their countries would be carbon-neutral by 2050 or a little bit later. Richer countries generally opted for 2050, while China and India, for example, aimed for 2060 and 2070, respectively. The promise of carbon-neutrality by 2050 (or 2060, or 2070) is a cheap promise, however, as the target is so far in the future that it doesn’t...
Some Further Comments on Climate Sensitivity and Warming Estimates
While preparing an update of Carbon-Neutrality by 2050 (by far the most accessed page in this blog), I had another look at (equilibrium) climate sensitivity (ECS), a topic about which a wrote a few times before. ECS is the expected global temperature anomaly (i.e., the expected global average of warming) at twice the pre-industrial level of greenhouse gases (mainly CO₂) in the atmosphere (i.e., 560ppm, as “pre-industrial” is set at 280ppm). The currently most widely accepted estimate of ECS is that by Steve Sherwood and colleagues, who suggest average warming of 3.1°C (median; 66% uncertainty range: 2.6~3.9°C; 95%: 2.3~4.7°C). However,...
Capitalism and Climate Collapse
The claims that capitalism is the cause of climate change and that catastrophic climate collapse cannot be avoided under capitalism are as obvious to some people as they are nonsensical to others, but really they are neither. They are probably true, which implies that they are not nonsensical, but their (probable) truth is not obvious. They are not obvious, because these claims depend on four other claims that are themselves non-obvious: (1) capitalism requires economic growth; (2) economic growth requires energy growth; (3) energy growth requires extensive use of fossil fuels; and (4) extensive use of fossil fuels causes climate...
SotA-R-10: Combined Models 4 and 5 Suggest 62% Change of Exceeding 3°C of Average Global Warming
(This is part 9 of the “Stages of the Anthropocene, Revisited” Series (SotA-R).) The previous episode in this series explained a few problems of the last iteration of the model used to better understand feedbacks between climate change and socio-political and economic circumstances (i.e. “Model 4”). Additionally, in another recent post, I mentioned that the relation between atmospheric carbon and warming is probably better treated as linear, with time lag explaining the discrepancy between a linear equation and the current level of warming. Furthermore, that post also addressed the issue of tipping points (and other neglected feedbacks), leading to an...
Tipping Points, Permafrost Thaw, and “Fast” Reduction
Last Thursday a new analysis of the main “tipping elements” in the Earth system was published in Science., The paper and its supplementary materials provide data on likely thresholds and effects of all the main tipping elements that have been discussed in the literature of the past two decades. Furthermore, the supplementary materials also discuss a number of other feedback effects that have been suggested as tipping elements before, but that turn out to be too gradual to be properly classified as such. These effects are at least as important, however, and tend not to be (fully) included in common...
Carbon-neutrality by 2050 (version of June 2022)
(Originally published on December 15, 2020. This version: June 13, 2022. The latest version can be found here.) In the year before publication of the original version of this article (2020) several governments announced that their countries will be carbon neutral by 2050. (Since then, other countries have joined them, but often with different target years. China and India, the world’s two most populous countries, aim for 2060 and 2070, respectively, for example.) This is a cheap promise, as the target is so far in the future that it doesn’t commit them to do any significant now, but even if...
Carbon-neutrality by 2050 (version of December 2020)
(Some corrections were made in this article on March 2, 2022. The most recent version of this article can be found here.) This year several governments announced that their countries will be carbon neutral by 2050. This is a cheap promise, as the target is so far in the future that it doesn’t commit them to do anything significant now, but even if the commitment would be real, one may wonder how probable it is that the target will actually be reached, and whether it will be enough. These are two different questions, of course, and I will try to...