[{"categories":null,"contents":"There\u0026rsquo;s a strong heatwave in Texas. Who\u0026rsquo;s to blame? Whodunit, or more precisely, whatdunit? Like the police captain in the movie Casablanca, the media reacted to the heatwave by rounding up a gallery of usual suspects:1 climate change, El Niño, wobbly jetstream, wavy polar vortex, and more. But what do the facts tell us? Is it a complex web of causes or just a couple of key factors?\nUnlike murder mysteries and media musings, science focuses on simple explanations.","date":"2023-07-06T00:00:00Z","description":"Did the flapping of a butterfly's wings in Brazil (or elsewhere) cause a heatwave in Texas? Yes, and climate change made it worse. That's the simple explanation.","permalink":"https://metamodel.blog/posts/texas-heat-wave/","tags":["Texas heatwave","global warming","climate change"],"title":"Texas Heatwave and Occam's Razor"},{"categories":null,"contents":"WMO\u0026rsquo;s afraid of the Big Bad El Niño.\nThe World Meteorological Organization (WMO) says there\u0026rsquo;s now a 66% chance that we will breach the 1.5°C global warming threshold between now and 2027, as reported in a recent BBC article.1 This increased probability is being blamed on the heat expected from an imminent El Niño. While noting any such breach will be temporary, the article goes on to say that “breaking the limit even for just one year is a worrying sign that warming is accelerating and not slowing down.","date":"2023-06-16T00:00:00Z","description":"El Niño is not Global Warming (except in Global-average Land). They have different physical causes and different spatial impacts, even though, arithmetically, they both raise global-average temperature.","permalink":"https://metamodel.blog/posts/big-bad-el-nino/","tags":["El Niño","global warming","climate change"],"title":"Who's afraid of the Big Bad El Niño?"},{"categories":null,"contents":"The previous post on this blog on March 1st analyzed the climate stress for US banks proposed by the Federal Reserve. Just over a week later, Silicon Valley Bank (SVB), a medium-sized bank in the US, experienced a financial stress test — a bank run fueled by social media.1 Responding to rumors that the bank was in trouble, customers rushed to withdraw their money. The bank ran out of cash and was shut down.","date":"2023-03-31T00:00:00Z","description":"Just as there's no precise global interest rate threshold for bank runs, there's no precise global warming threshold for climate tipping points. But higher values increase risk. And timescales matter.","permalink":"https://metamodel.blog/posts/bank-run-climate/","tags":["climate change","tipping points","bank run","financial risk","climate risk","interest rate","uncertainty trough","certainty trough"],"title":"Bank runs and tipping points: Parallels between finance and climate"},{"categories":null,"contents":"Recently, the US Federal Reserve (\u0026ldquo;Fed\u0026rdquo;) issued guidance for a pilot exercise on how the six largest US banks should analyze their exposure to climate risk.1 The Fed calls the study exploratory and says the results will have no capital implications. Nevertheless, this exercise is essentially a climate stress test—like the financial stress tests to check whether banks have enough capital to survive economic shocks. Other central banks around the world are taking similar steps.","date":"2023-03-01T00:00:00Z","description":"The Fed’s new hurricane-based risk assessment is well-intentioned but poorly formulated. Since future hurricane probabilities are hard to predict, a simple storyline approach would have been better.","permalink":"https://metamodel.blog/posts/fed-climate-risk/","tags":["climate risk","Federal Reserve","financial risk","“climate stress test”"],"title":"Hurricane Fed: The New Climate Stress Test for Banks"},{"categories":null,"contents":"Imagine that our universe is just one slice of bread in the grand cosmic loaf of the multiverse.1 That’s a popular description of the physics concept of the multiverse. But the multiverse is not considered essential for everyday applications of physics, even if it makes for good pop-sci narratives. If one were to use Occam’s Razor to slice up the multiverse loaf, one could even argue that the concept of the multiverse adds unnecessary complexity.","date":"2022-08-02T00:00:00Z","description":"We cannot predict our weather universe but we can choose our emission multiverse","permalink":"https://metamodel.blog/posts/climate-multiverse/","tags":["model democracy","meritocracy","metrics","model tuning","IPCC","CMIP"],"title":"Strange weather in the multiverse of climate"},{"categories":null,"contents":"If we build a gigantic supercomputer, ask it the ultimate question, and receive a single number as an answer, what have we learned? Without context, not much. A single number, whether it is 42, as in The Hitchhiker’s Guide to the Galaxy,1 or 3°C for Earth’s climate sensitivity, doesn’t mean much unless we know how it was calculated and what its uncertainty is.\nThis provides a nice segue to the recent blog discussion about a concerted international effort to build a climate model with a 1-km (k-scale) horizontal grid.","date":"2022-07-13T00:00:00Z","description":"Irreducible uncertainties associated with internal variability and human actions limit our ability to predict long-term climate change. Higher model resolution can help, but it is not a silver bullet.","permalink":"https://metamodel.blog/posts/model-expectations/","tags":["k-scale","km-scale","high-resolution","climate model","uncertainty","stochastic","chaos","internal variability"],"title":"What to expect when you’re expecting a better climate model"},{"categories":null,"contents":"What happens when the startup mantra “fake it till you make it” is taken to the extreme? It doesn\u0026rsquo;t end well. It happened with WeWork, a real estate company that was pretending to be a tech company. It also happened with the Silicon Valley unicorn Theranos that promised to revolutionize blood testing using a pinprick, but faked test results and failed to make it. The high-profile startup was brought down by an investigative reporter and an inspector from a “boring” government agency that regulated medical testing.","date":"2022-06-28T00:00:00Z","description":"Theranos, WeWork ... Carbonos? With startups selling products that affect the planet’s health, physical checks are more important than fancy crypto. The wild west of carbon offsets needs a sheriff.","permalink":"https://metamodel.blog/posts/climate-crypto/","tags":["climate solutions","carbon offsets","nature-based solutions","startups","blockchain","crypto","cryptography","Theranos","WeWork","Carbonos"],"title":"Climate Startups, Carbon Offsets, and Crypto"},{"categories":null,"contents":"Is life worth living? It depends on the liver. So goes the old joke. Is life worth living in a warming climate? The answer might be: It depends on the wet-bulb temperature. Like the state of the liver determines whether you can drink alcohol, the value of the wet-bulb temperature determines whether you can survive without air conditioning — if the value exceeds 35°C, you just cannot.\nWet bulb temperature is an obscure meteorological metric that has gained prominence lately because it measures human survivability.","date":"2022-06-22T00:00:00Z","description":"Many assumptions lurk behind climate risk assessments. Small errors in the average can mean large errors in the tail risk.","permalink":"https://metamodel.blog/posts/predict-perils/","tags":["climate risk","tail risk","mckinsey","heat wave","wet-bulb temperature"],"title":"The perils of predicting perils: (mis)calculating wet-bulb temperature"},{"categories":null,"contents":"If you want to make a prediction, you better make sure that you’re either in sample, or that you know the differential equation. 1\n In discussions of global warming, you sometimes hear arguments that you can\u0026rsquo;t trust the complex climate models, that we should rely solely on data to predict the future, and that we should observationally constrain model predictions. This leads us to ask: Can we predict global warming using only statistics?","date":"2022-06-07T00:00:00Z","description":"Not if it is unprecedented and nonlinear. You can't do statistics with a sample size of less than one. Science is our only hope.","permalink":"https://metamodel.blog/posts/using-only-statistics/","tags":["Explainer","statistics","statistical models","global warming","emulators","correlation"],"title":"Can we predict global warming using only statistics?"},{"categories":null,"contents":"Each individal article on this blog can be downloaded as an ePUB or PDF for offline reading using an e-reader. Look for the download buttons below the article subtitle/author name when viewing the article.\nYou can also download a collection of articles as an eBook in ePUB/PDF formats:\n  Five most recent posts: ePUB / PDF\n  All posts: ePUB / PDF\n  These eBooks are updated every time a new article is posted.","date":"2022-05-26T00:00:00Z","description":"","permalink":"https://metamodel.blog/page/ebook/","tags":null,"title":"eBook"},{"categories":null,"contents":"Climate target numbers are approximate. Their roundness reflects that.","date":"2022-05-24T00:00:00Z","description":"Climate target numbers are approximate. Their roundness reflects that.","permalink":"https://metamodel.blog/posts/why-round-numbers/","tags":["Explainer","threshold","1.5 degrees","net-zero"],"title":"Why are the (climate) numbers so round?"},{"categories":null,"contents":"Every 6\u0026ndash;7 years, major climate modeling centers around the world submit their climate simulations to an organization called the Coupled Model Intercomparison Project (CMIP). CMIP distributes the simulation data so that scientists around the world can analyze and compare the models. But what criteria should we use to judge or rank models? How do you decide whether one model is better than another? Do we care about superficial beauty or inner beauty?","date":"2022-05-10T00:00:00Z","description":"Model meritocracy is a good idea, but the devil is in the details","permalink":"https://metamodel.blog/posts/model-meritocracy/","tags":["model democracy","meritocracy","metrics","model tuning","IPCC","CMIP"],"title":"How to judge a model beauty contest?"},{"categories":null,"contents":"If the globe warms slightly beyond 2°C, will we cross a climate tipping point that leads to runaway warming or catastrophe? Are we doomed if we don\u0026rsquo;t stop the warming by 2030 (or 2050)? Predictions of imminent climate tipping points often capture the imagination of the media and the public. Aren\u0026rsquo;t the harmful consequences of a steadily warming climate and its effect on extreme weather bad enough to spur action? Do we need even more things to worry about?","date":"2022-05-03T00:00:00Z","description":"Nonlinearity generates tipping points, but it also make them hard to predict","permalink":"https://metamodel.blog/posts/predict-tipping-points/","tags":["Explainer","threshold","tipping point","1.5 degrees","net-zero"],"title":"Can we predict global climate tipping points?"},{"categories":null,"contents":"Metamodel: a model that consists of statements about models.\nThis is a blog about the language, science, and philosophy of predictive modeling. The aim is to be more whimsical than polemical, and mostly non-technical. The discussions will generally be about climate models, which are arguably the most complex models ever built. But models from related fields will make a guest appearance now and then. The discussions will frequently venture beyond science because the prediction of long-term climate change is now so intertwined with the cultural milieu that it is impossible to discuss it within a purely scientific context.","date":"2022-01-27T00:00:00Z","description":"","permalink":"https://metamodel.blog/page/about/","tags":null,"title":"About this blog"},{"categories":null,"contents":"Disclaimer Rights Commenting Privacy  Disclaimer This is a personal blog. The opinions expressed here are my own and do not in any way represent the official opinions of my employer.\nCommenting To provide feedback on any post, you have two options:\n  You can use Twitter to simply reply to the tweet announcing the blog post, which is displayed at the end of each post.\n  If you don\u0026rsquo;t wish to use a tweet for your comment, or if your comment is too long, you can comment on the post at metamodel.","date":"2022-01-27T00:00:00Z","description":"","permalink":"https://metamodel.blog/page/policy/","tags":null,"title":"Blog Policy"},{"categories":null,"contents":"Substack mirror of this blog  Personal\n  Website\n  Book page\n  Twitter profile\n  A few other climate modeling blogs\n  Real Climate\n  …and Then There\u0026rsquo;s Physics\n  Serendipity\n  Bryan Lawrence\u0026rsquo;s Blog\n  Isaac Held\u0026rsquo;s Blog\n  Podcasts related to climate prediction\n Deep Convection  Useful climate resources\n CarbonBrief.org Reporting extreme weather and climate change: A guide for journalists (WorldWeatherAttribution.","date":"2022-01-27T00:00:00Z","description":"","permalink":"https://metamodel.blog/page/links/","tags":null,"title":"Links"}]