School zone

  By Daniel Medina and at BlueSky

How fast is Earth warming?

 From Open Mind (Tamino)

[By 0.3 to 0.4 degrees C per decade]

Another paper has appeared showing an increase in the rate of global warming since about 2011, and using their new rate estimates to forecast when we will pass the 1.5°C and 2°C thresholds of global temperature warned about in the Paris agreement. Since there’s little doubt left that warming accelerated recently, the question becomes “By how much?” Different methods of analysis give different answers, and estimates from this latest research are very high indeed.

After scanning global temperature data sets, they settled on the year 2011 as a “changepoint” when the warming rate increased and estimated its value before and after that. They did so by fitting data from 1970 through 2010, and from 2011 through 2025, separately, using the Theil-Sen slope estimate. It is a robust, non-parametric method which, since it is applied separately to separate time spans, produces a fit which is discontinuous, i.e. at the changepoint time temperature shows a jump as well as a slope change.

Since the pertinent question is “What’s the warming rate since 2011?”, I’ll answer that with three methods. One is a least-squares regression to the data since 2011. Another is the Theil-Sen slope estimate over that same interval (as done in the new paper). Last, I’ll use a PLF (Piecewise Linear Fit) which allows for a slope change but does not allow a jump discontinuity, and it too can be fit by least squares regression. Thus I can use models with and without jump discontinuity at the changepoint time (which I call “L.Sq.” and “PLF”), and here’s what they look like when fit to the global temperature data from HadCRU (yearly averages as black dots, L.Sq. fit as blue line, PLF as red line):

Here’s a close-up on the time since 2011, showing yearly averages (from HadCRU) with both the L.Sq and PLF fits, as well as a dashed line showing the best-fit line estimated by the Theil-Sen method:

From this it’s clear that of the three methods, the PLF gives the lowest slope while the Theil-Sen estimate gives the highest. It’s also worthwhile looking at the uncertainty ranges for all three methods when applied to various data sets; here are the rates for each (blue x’s for L.Sq, black dots for Theil-Sen, red triangles for PLF) and their 95% confidence ranges:

It’s clear that for all four data sets, the highest warming rate estimate comes from the Theil-Sen analysis, the lowest from PLF. It’s also clear that the error bars for PLF cover a smaller range (i.e. the PLF rate estimates are more precise), because the PLF model requires the underlying trend to be continuous across a changepoint. None of which addresses any of the further uncertainties in the problem.

I would emphasize that whatever method is chosen, the uncertainties are sizeable. The global warming rate, even after the recent acceleration, might be merely 0.025°C/yr (0.25°C per decade) or as high as 0.06°C/yr (0.6°C per decade). The high end of that range is more than twice the low end, and if the planet heats up that much then by the year 2050 we’ll not only pass 1.5°C and 2°C, we’ll be well past 2.5°C. Even at the lower end of the range we’ll still cross 2°C by the year 2050.

This does not look good.

We're looking at a rise in global temperatures of somewhere between 0.3 and 0.4 degrees C per decade.  We might be lucky, and it's at the lower end at just 0.25 degrees per decade.  Or unlucky, and it's 0.6 degrees.  If we use the PLF estimate, which is the lowest, we're looking at 0.3 to 0.35 per decade.  We shouldn't assume we're going to get lucky.  Prudence suggests that we assume it'll be at the higher end, and accelerate the roll-out of renewables, EVs, and heat pumps.  And, as I've said before, you can at least cut your own emissions by giving up meat.  And if it isn't at the higher end, good.  Every 0.1 degrees C that global temperatures rise is worth being avoided.

World Central Bank discount rates keep on rising

Some went up sharply (Uganda's, by a swingeing 2.25%, because its currency is collapsing) while others fell almost as sharply (Zambia's, because of falling inflation).  But on average, they have continued to rise, with the US and the Euro area the biggies.  Since inflation, driven by the Iran war, hasn't yet peaked and looks unlikely to in the short term, expect Central Banks to keep on tightening, with obvious consequences for share markets and the global economy.  This is on top of the economy-crunching effect of a rapid rise in oil prices (see lower chart).

'83% of world' is the weighted average of countries making up 83% of world GDP.
'Median' is the middle of the range of DRs for all the countries I monitor for each day
'Unweighted average' is the simple average (mean) of all countries I monitor.

Oil prices are heading back towards their cyclical high for this cycle $118.  (Previous cyclical highs: March 2022, $129.49; July 2008, $143.57)

AI is an abomination

Cartoon by Tom Fishburne

Let's think this through.

The reason AI is supposed to be the next big thing is because companies believe they will be able to replace workers with it.    Getting rid of all those pesky humans, how nice is that!!  If AI works, it will erase hundreds of millions of jobs — receptionists, waitstaff, junior clerks, and so on and so on.  This will push up unemployment, for ever.  Ordinary people will be much worse off, and the economy much weaker.  Ironically, though it would temporarily help the profits of the company which sacks workers and uses AI to replace them to rise, when every company does this, who will be buying their products?  The AI spruikers assure us that, somehow, new jobs will be found.  The Techbros mutter about UBI (universal basic income) but since they work very hard to not pay any tax at all, including buying elections, who, out of the few who will still have jobs, will be paying the taxes to provide a UBI?  You can depend upon it:  it will not be the techbro billionaires.

Each data centre will use the power a small city uses, but it will use it in a much more concentrated area.  Reports have stated that local temperatures outside data centres are 4 to 8 C hotter than temperatures a mile away.  The noise from the generators has forced people to move away.  Data centres will guzzle water (for cooling) and power.  The power won't come from renewables either.  It'll come from gas turbines and diesel.  And what happens if there's a drought or not enough electricity?  Who do you think will have their supply cut, the date centres or the people?  The insane demand for power will prevent emissions from falling, in a world where the rise in temperatures per decade has already increased from 0.2 to 0.3 degrees C per decade.

And, of course, the training of AI.  Books, works of art, music, Wikipedia — everything is grist to their mill.  Physical books are being destroyed to feed chatbots.  It doesn't matter that you have slaved and slogged to create something worthwhile, AI will steal it.  Without compensation, without even asking.  And the profits will accrue to large companies and billionaires.  Who don't pay tax.  

It gets worse.  If AI is good enough, it will make everybody question whether any video or image or story or piece of music is real.   We won't know what's true or false any more.  People will stop believing anything they see.  How will we choose what's best to do? How will we set policy?  AI has poisoned everything.

AI will stop people thinking.  It will lead to a huge dumbing down of our society, even more than has already happened.   Lazy people will outsource their thinking to some techbro's evil demonic creation.  They will become unable to think for themselves. 

Then there's the "hallucinations".  These are entirely fictitious references in legal or other documents made up out of whole cloth.  The entire basis of finding out the truth is being destroyed.  AI slop is everywhere.  

And the "breakouts", where "rogue" AIs infect other computer systems?  Do you realise how many of our critical systems depend on computers to function?  The grid.  The telephone system.  Air traffic.  Banking.  Transport.  Modern cars.  What happens when these systems are corrupted by AIs which have escaped from the lab?  How many people will die?  How many societies will collapse?

Let's not even talk about Skynet.

AI is an abomination.  It will destroy us. 

The best transport for low emissions

 From Our World in Data

Transport accounts for around one-quarter of global carbon dioxide (CO2) emissions from energy.1 In some countries — often richer countries with populations that travel often — transport can be one of the largest segments of an individual’s carbon footprint.

If you need to travel locally or abroad, what is the lowest-carbon way to do so?

In this chart, we see the comparison of travel modes by their carbon footprint. These are measured by the amount of greenhouse gases emitted per person to travel one kilometer.

These data come from the UK Government’s Department for Energy Security and Net Zero. They're the emission factors companies use to quantify and report their emissions. While the overall rankings of transport modes will probably be the same, there may be differences across countries based on their electricity mix, vehicle stock, and public transport network.

Greenhouse gases are measured in carbon dioxide equivalents (CO2eq), accounting for non-CO2 greenhouse gases and the increased warming effects of aviation emissions at high altitudes.2

Over short to medium distances, walking or cycling is nearly always the lowest carbon way to travel. While they’re not in the chart, the carbon footprint of cycling one kilometer is usually in the range of 16 to 50 grams CO2eq per km depending on how efficiently you cycle and what you eat.3

Using a bike instead of a car for short trips would reduce travel emissions by around 75%.

[Remember that the carbon dioxide we breathe out was originally extracted from the air by plants, so with walking or cycling, it's not a net addition to atmospheric CO2.  But in the case of the meat we eat, there are also methane emissions to consider, and methane is 80 times as potent a greenhouse gas as CO2, and the plants don't breathe in methane.]

"National Rail" means all the railway companies except London Transport, and includes diesel and electrified routes.  The reason Eurostar to Paris is so much lower is because France's electricity is mostly generated by nuclear.  

For flights of less than 1000 km, the carbon intensity is very high, but falls as the flights lengthen, until about 3,500 km, after which it doesn't decline any further.  Most carbon emissions from flying come from short-haul flights.   

The lowest emissions per kilometre are in public transport, and if the grid was 100% renewable, and all public transport was 100% electric, emissions per kilometre would be much lower, coming only from emissions released during manufacture and construction.

E-buses presumably have much lower emissions than diesel buses.

Transport emissions are falling as EV sales take off, but to really cut emissions, we will need to deal with air travel.  Electric planes are a start, but the biggest e-plane won't be going into service for at least another 2 years, and it won't (yet) be able to fly on intercontinental routes.  In the meantime, where you can, use the train or bus or your EV.

Note also that this doesn't address emissions from shipping.  Ironically, 40% of shipping emissions are from moving fossil fuels (coal, oil and LNG).  

Australia's EVs surge

 Australia's EV and PHEV sales surged to 35.6% of total car sales in August 2026.  In August 2022, EVs made up just 4.7% of total sales.

Will sales decline when the Iran war is eventually over?  It's possible.  But even without the rise in fuel prices which occurred as a result of the war, EVs are still much cheaper to run than petrol/diesel cars.  And now they're also cheaper to buy.  People who bought an EV have given confidence to others who have worried about switching.  The rise in the number of EVs will lead to a surge in new chargers.  It will only get easier to run your EV as the charging infrastructure rolls out.

And truly, the cheapest EVs are very cheap.  The cheapest car in Australia is an EV, the BYD ATTO 1.  It has a low range (220 km), but is dirt cheap to run.  If you're poor, it's not going to be a burden to stop off and recharge on long routes, just as it isn't for, say, Pakistanis or Thais.  

This is an unstoppable revolution.  The S-curve has flexed upwards, and will continue steepening until we get to 90 or 95% penetration.  And that's true everywhere — except the USA.

Source: EMBER

Leaf globe

 By Dave Coverly