Dork Scratchings

I just read this fascinating book by Jean-Baptiste Fressoz .  The premise is that there has never been a transition from one energy source to another (e.g. wood -> coal, or coal -> oil) and that, by contrast, novel sources of energy have simply piled up on top of each other.  Worse still, each new form of energy - and also each new material - has simply enabled increased consumption of each other form of energy and form of material. The conclusion is stark, supporting renewables will not be enough to avert a climate catastrophe.  As the book says: it may be a necessary condition but it is not a sufficient one.  For me, the most interesting part of the book was this diagram, taken from a 1983 Environmental Protection Agency report titled "Can We Delay a Greenhouse Warming?"  which used an energy model developed by Oak Ridge Laboratories:   The graphic shows how different scenarios and policies affect the date at which +2C warming is breached.  Not...

Nearly two weeks into the US-Israeli war on Iran many commentators have drawn attention to the climate cost of war.  But whether it's the BBC's Climate Question  on Radio 4, or Covering Climate Now's Press Briefing , they all ignore the elephant in the room: the blockade of the Straits of Hormuz.  So, what is the effect on the climate of this blockade? Saving Lives at Sea I made a meme, plz share... How many lives are saved by stopping a single tanker?  Estimates of the number of climate deaths this century vary enormously, with some sources saying around 10 million and others many billions.  There are plenty of serious climate scientists who believe most lives on Earth are at risk.  But let's follow this study  which says "The number of caused deaths will likely lie between a tenth of a person and 10 people per 1,000 tons." A typical tanker carries 1,000,000 barrels of oil, which when burned will create 430,000 tons CO2.  If we treat all anthropo...

Ever since the blackout that affected much of Spain , I've been wondering how it's going to work when renewable power starts to approach 100% of the power supplied by the grid.  That blackout may have been caused by a number of different factors, but the forces of evil were quick to point out that one thing that  may  have caused it was that there was too much renewable energy in the grid at the time. Renewable energy such as solar comes naturally in DC whereas the grid supplies AC at 50Hz (in Europe anyway).  This means that before it can be fed into the grid it has to be passed through an "inverter" to turn it into AC.  This is typically done by phase-locking to the grid signal, which is fine until the supply approaches 100% renewable at which point the question becomes: but who is setting the frequency?  I'm not sure whether or not this really was an issue in Spanish blackout, but it's a reasonable question to ask. A pretty good answer was provided by a...

Here's an image you're probably familiar with: it's the BBC News website banner.  The space between "InDepth" and "UK" is reserved for quick links to the most important issues of the day, and right now it reads "Israel-Gaza war | War in Ukraine | Climate".  It's fair to assume that the highest priority issues are closer to the left, based on how frequently these issues end up in the headline article. So, I wondered, how has the priority - according to the BBC - of the biggest issues changed over time?  I decided to sample the website using the wayback machine , once per year from September 2020 to September 2025, and here's the result:   Over these 6 years the BBC News banner has had between 1 and 4 quick links.  And it seems to be a consistent feature that whenever a new story comes along that threatens fewer lives, it takes a higher priority position in the banner.  "Climate" didn't turn up until 2022, and when it did it...

Dork Scratchings has finally decarbonised!  The first to go was the fossil fuel investing pension (this has been replaced by PensionBee's fossil fuel free plan ), then went the petrol car (replaced by an electric 208), and this week we got rid of the boiler. The new heating system is a Mitzubishi heat pump which heats water by extracting heat from cold air.  The laws of Thermodynamics set a limit on the amount of heat energy that can be produced per unit of electrical energy and the formula is $$ \frac{T_H}{T_H-T_C} $$ Where $T_H$ is the temperature of the hot water ($50^\circ C$ in our case), and $T_C$ is the temperature of the cold air outside the house.  Note that the temperatures have to be in Kelvin to make this work, and the value drops as the outside temperature drops.  For example, for $50^\circ C$ water, it is 12.9 when the outside temperature is $25^\circ C$ but only 6.5 when the outside temperature is $0^\circ C$.   The heat produced per unit of ...

Rolling marbles  Here's a puzzle: Suppose you have N identical marbles rolling along a one dimensional table-top.  Each marble is randomly rolling to the left or to the right, all with the same speed.  Collisions are elastic, which means the marbles just change direction.  What is the maximum amount of time before all the marbles have rolled off the table? 8 marbles with speed 1 on a table of length 1 Answering this question is really difficult if you simply pick an individual marble and try to work out how long it might stay on the table as it bounces back and forth.  But there's a simpler way to look at it. Prior to each collision you have one marble rolling to the left and one to the right, and afterwards you still have one rolling to the left and one to the right.  If we swap labels following each collision then the labels never change direction.  Now it's easy to see that the answer is the same whether there are 100 marbles or just one.  And ...

Contents Intro Simple stratified model Alternative convection model Tropospheric temperature gradient Approach used in convection model Calculation of Radiative Forcing from CO₂ increase Calculation of Radiative Forcing from H₂O increase Calculation of zero-feedback ECS Effect of including feedbacks Effect of water vapour Effect of cloud cover change Effect of sea ice loss Calculation of ECS including feedbacks Limitations One more thing: Changes to Troposphere depth Intro The goal of this post is to see if we can come up with an estimate of Equilibrium Climate Sensitivity using a simple model in which the atmosphere is treated as well-mixed.  By "simple" I mean that using the model will not require any advanced mathematics or computation, but will still be realistic enough to come up with an estimate within the likely range of 2.5 - 4.0°C predicted by the IPCC Assessment Report 6 .  I will try to take as little on trust as possible and show how the results are arrived at....

It may be a sign we're close to one or more tipping points The latest report from the Intergovernmental Panel on Climate Change is known as Assessment Report 6, or IPCC AR6 for short.  Rather than contain new research, AR6 summarizes the latest work of climate scientists, and synthesizes thousands of papers.  An important element of this are the climate models.  The climate models examined by AR6 are called CMIP6 models, for Coupled Model Intercomparison Project v6. Climate models can provide answers to "what if?" questions.  Some of these What Ifs are described by the IPCC in their Shared Socioeconomic Pathways, or SSPs for short.   But these What Ifs combine questions about physics (how the Earth will respond) with assumptions about our future behaviour.  What we would like is to be able to factor out the human influence and get a single number that measures just how sensitive the Earth's climate is to CO2?  That's where Equilibrium Climate Sensitivi...

The Saudi British Joint Business Council and... ...a Perpetual Motion machine!   I spent yesterday wandering around the London Climate Technology Show, and I had many interesting conversations.  There were way too many middlemen selling questionable climate offsets.  These all provided an account and a fancy online dashboard for companies wanting to demonstrate their carbon neutrality.  At least 4 of the companies were using Blockchain as a buzzword.  The idea is that you write a contract with the farmer/landowner/whatever to improve soil carbon/not cut down trees/whatever and then you sign that contract and put it in an online ledger like the Ethereum blockchain.  This prevents the existence of the contract being denied and enables ownership to be transferred, like with digital coins.  Although in principle this can work it requires a single joined up database.  With multiple companies offering the same service, but on incompatible systems, the...

Rough and ready order of magnitude calculation: Cows burp 100kg methane each year, which lasts 10 years before decaying in the atmosphere, and has about 100x the warming potential of carbon dioxide while it's up there. Cows (and other ruminants such as sheep) continuously burp CH$_4$, a powerful greenhouse gas.  In fact, gram for gram methane warms the planet 87 times more than carbon dioxide .  However, CH$_4$ reacts in the atmosphere so that the carbon atom eventually finds itself in a CO$_2$ molecule.  We can think of it as having an atmospheric half life of about 8.6 years .  For this reason, the Global Warming Potential (GWP) of methane is sometimes averaged over 100 years to give a GWP100 figure of 27-30, i.e. twenty seven to thirty times as powerful (over 100 years) as carbon dioxide. Methane enters the atmosphere from a number of sources.  Two significant ones are biogenic sources such as cows, and fossil sources, such as when unwanted methane is flared ...

Background ECS - Equilibrium Climate Sensitivity - is the temperature change on Earth as a result of a doubling of atmospheric CO2.  That means going from 280 ppm (the level prior to the industrial revolution) past 420 (where we are now) and on to 560 ppm.  Most people probably understand why this would increase temperatures by now, but I'm going to repeat the argument briefly anyway, for completeness

Fossil Fuels are dragging your pension down!   At the end of last year I finally managed to switch to a fossil fuel free pension.  The journey wasn't completely straightforward, but it was worth it and hopefully this will become a lot easier in the near future. Why do this? There's a bunch of things you can do to reduce your carbon footprint including giving up flying and eating less meat, and I recommend all of them.  But right at the top has to be to stop investing in fossil fuel companies.  A typical pension pot in the UK is around £88,000 of which - typically - 4% is invested in oil, gas, and coal.  That's three and half grand of your money going directly to the likes of ExxonMobil.  If you simply spent this much on tax free petrol it would buy you about 8.8 tons of fuel which would create about 29 tons of CO2, or about 5x the annual emissions of an average Brit.  But investing probably results in an order of magnitude more emissions $^\dagger$ ...