On āPessimismā and āOptimismā about Climate Change; and on SRM as a āCheap Fixā
Letās imagine the most optimistic climate change scenario for a century from now, without going completely bonkers. To do that, letās first split up greenhouse gas emissions (COā-equivalent or āCOāeā) into non-residual and residual emissions. The latter are emissions that are difficult or impossible to (fully) eliminate due to technological or other limitations. In our scenario, non-residual emissions ā that is, emissions that we can actually reduce with current technology and without disastrous socio-economic impacts ā continue to grow a little bit for a while (as they do in reality), but the curve starts bending down soon (which is a...
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: $$ \Delta T_{anom.} = \frac {ECS \times ( C_{atm.} ā 280 )} {280} \: – \: \psi,$$ in which \(\Delta T_{anom.}\) is the average temperature anomaly (or average global warming), \(ECS\) is āEquilibrium Climate Sensitivityā, \(C_{atm.}\) is atmospheric carbon (in ppm COā equivalent), and \(\psi\) (from Greek Ļįæ¦ĻĪæĻ, meaning ācoldā) 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 doesnāt...
The Probability of the End of Civilization in the 21st Century
Climate scientists have been calling recently for more research into warming scenarios of 3Ā°C and above because such scenarios are dangerously neglected. According to mainstream models such levels of warming are by no means impossible or even unlikely, and would have catastrophic effects. Luke Kemp and ten colleagues write: Could anthropogenic climate change result in worldwide societal collapse or even eventual human extinction? At present, this is a dangerously underexplored topic. Yet there are ample reasons to suspect that climate change could result in a global catastrophe. The answer to the question in this quote is obviously āyesā, but thatās...
SotA-R-7: Current Models Predict 4Ā°C of Global Warming
(This is part 7 of the āStages of the Anthropocene, Revisitedā Series (SotA-R).) Important Note (March 3, 2022) Due to a fundamental flaw in models 1, 2, and 3 in this series, the predictions for average global warming in this article are unreliable. Update (May 21, 2022) Model 4 fixes this problem and predicts +3.7Ā°C. Thereās no plausible peaceful path to carbon-neutrality. If thereās one key takeaway from my attempts to model carbon (COā-equivalent) emissions in stage 1 of the anthropocene, itās that. Oh, and thatās it will get hot, of course. Unpleasantly hot. This the fourth in a series...
SotA-R-6: Modeling Carbon Emissions ā New Results, and Thoughts on Further Models
(This is part 6 of the āStages of the Anthropocene, Revisitedā Series (SotA-R).) Important Note (March 3, 2022) Due to a fundamental flaw in models 1, 2, and 3 in this series, the predictions for average global warming in this article are unreliable. Update (May 21, 2022) Model 4 fixes this problem and predicts +3.7Ā°C. As mentioned in the section ālimitations and alternative approachesā of the previous episode in this series, there were a couple of things I wanted to change in the model (i.e. spreadsheet) used to simulate global carbon (COā-equivalent) emissions in stage 1 of the anthropocene. The...
SotA-R-5: Modeling Carbon Emissions in Stage 1 of the Anthropocene ā a First Attempt
(This is part 5 of the āStages of the Anthropocene, Revisitedā Series (SotA-R).) Important Note (March 3, 2022) Due to a fundamental flaw in models 1, 2, and 3 in this series, the predictions for average global warming in this article are unreliable. Update (May 21, 2022) Model 4 fixes this problem and predicts +3.7Ā°C. The aim of this series is a better prediction of the long-term prospects for human civilization (in the context of climate change) than the rather sketchy predictions made in Stages of the Anthropocene three years ago. The previous episodes in this series discussed some relavant...
SotA-R-4: Preliminary Notes on Modeling Carbon Emission Scenarios in Stage 1 of the Anthropocene
(This is part 4 of the āStages of the Anthropocene, Revisitedā Series (SotA-R).) The purpose of this series is an update of the mid- and long-term prediction of aspects of the global climate relevant for the prospects of continuing human civilization in Stages of the Anthropocene. The idea is to develop a model that can be relatively easily expanded, fine-tuned, and corrected when new or better information becomes available. The present episode in the series consists of a number of notes of a relatively technical nature on how to build this model. COā emissions and economic growth The level of...
SotA-R-3: Heat and Cyclones
(This is part 3 of the āStages of the Anthropocene, Revisitedā Series (SotA-R).) Drought is (obviously) not the only kind of disaster caused by climate change, although it is probably the most severe in terms of its (long term) effects. Other types of ānaturalā disaster that have to be taken into account given the purpose of this series include heatwaves, storms, and other forms of extreme weather. The focus in the present article will be on heat and tropical cyclones (including hurricanes and typhoons). heat While there are several papers projecting aspects of heat as an effect of climate change,...
Stages of the Anthropocene, Revisited
(This is part 1 of the āStages of the Anthropocene, Revisitedā Series (SotA-R).) In Stages of the Anthropocene (2018), I argued that if one aims to make mid- or long-term predictions of the effects of climate change on human civilization, it is useful (if not necessary) to distinguish three phases or stages within the time period known as the āanthropoceneā. There is some disagreement about when the anthropocene started ā the industrial revolution (mid 18th century) and the advent of the atomic age (mid 20th century) have been suggested, and an argument has even been made for the emergence of...
(Not) Too Late for What?
Some people seem to believe that it is too late to fight climate change. Others seem to believe that this kind of fatalism is as dangerous as climate change denialism (because both effectively advocate not doing anything). Itās hardly a secret that Iām rather pessimistic about climate change and its effects ā just have a look at what Iāve written about the topic before ā but that doesnāt mean that I think that it is ātoo lateā to fight climate change. Rather, I think that the notion of it being ātoo lateā (or not) in this context is nonsensical. The...
Predictions
A year ago, I predicted that the Covid19 pandemic would kill 35 million or even more people. Although mortality statistics suggest that the current official death count (about two and a half million at the time of writing) significantly underestimates the real number of deaths, it is also becoming increasingly unlikely that weāll reach numbers anywhere near that pessimistic prediction any time soon. The reason why my prediction was so far off is the same reason why many other predictions fail: they insufficiently take into account that human behavior changes in response to changes in circumstances. Typically, models used to...