Author: Robert Wilson

Ignore the EFSA. This is the real science of caffeine

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I am currently in a state of outrage at a new “study” by the European Food Safety Authority. The EFSA, a body entrusted with keeping food safe, has just produced scientifically indefensible claims about caffeine. I know they are indefensible because I trust my body more than a bunch of badly trained chemists in Brussels.

These badly trained chemists have worked out that having more than 5 espressos a day will cause damage to your health. Piffle I say. And a real threat to the health of Europeans.

Here is why.

First, not all espressos are alike. A seminal study, carried out by high school students in Byres Road, Glasgow (10 minutes from where I live), showed conclusively that the caffeine content of espresso is all over the place.

Caffeine content of a Starbucks espresso is a well regulated 50 mg per shot, far too low as all thinking persons know. Costa Coffee, however, is 3 times greater.

Patisserie Francoise, an independent Glaswegian joint, takes it up one notch. They deliver 322 mg per shot, six times that of Starbucks.

Naturally, like all good scientists, I believe in replication. I rushed out to test the effectiveness of Patisserie Francoise’s medicine, but was sadly let down.

But there you go. “Don’t drink more than five espressos a day” is meaningless advice.

And that’s ignoring the real science.

I will now give it to you. And I am sure all scientists who have studied coffee each morning throughout their careers will agree with me here.

Performance is always zero when caffeine levels is zero. That is not a controversial issue, and it needs no further study. I will take it as read.

What happens when it goes up? There are three possible responses, and only three.

First, there is the linear response. It goes like this:


The evidence for this response is limited. However, it still has some dogged adherents within the scientific community.

Then there is the saturating response. After 4 or 5 cups of espresso the brain can’t take any more, and it just keeps going as before. There is no, note no, decline in performance; there is never a decline in performance.


The evidence that the above response holds on a Friday is robust (p value = 0.01).

However, on Mondays, Tuesday, and especially Wednesdays, the most credible response is the quadratic response (or as many commentators like to call it, the exponential response).


That dear reader is the real science of caffeine.


Wilson, R.J., 2015. Ten cups is better than one. The response of intellectual performance to caffeine intake. Science. In review.

Glen Peters on the infeasibility of 2 C

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I recommend watching this video of a talk by Glen Peters arguing that keeping global temperature increases to 2 °C is no longer plausible.

Peters arguments may be pessimistic, but they are hard to argue with. As I said last year limiting temperature increases to 2 °C will effectively require us to stop building new fossil fuel infrastructure in the next few years, or prematurely retiring existing infrastructure at an unthinkable rate. Neither of these things are credible.

Right now more new fossil fuel infrastructure is being added each year than ever before. The idea that the required reversal is going to occur is delusional.

The alternative to the near cessation of building new fossil fuel infrastructure within a decade, as Peters points out, is to build vast amounts of bioenergy with carbon capture and storage (BECCS). This technology does not exist, may not even be low carbon and will require vast amounts of land that will inevitably clash with the requirement to provide improved diets for the 9 billion or so people living by the of the century. Large-scale BECCS is not something to rely on.

Now, the obvious retort to all of this is to point to some study or other showing how it is technically and economically feasible to do all this. All we lack is political will. Political will! The resort to cliché is always a sure sign someone is on weak intellectual ground. And there is no bigger cliché in climate change than the claim that “all we lack is political will”. If we had the political will, here are a few things we could end quite quickly: racism, sexism, homophobia, religious superstition, poverty, rape, and herbal tea.

Yes, from a technical point of view we can do certain things. The question here is whether we will.

A couple of weeks ago a study was published in PLOS ONE claiming that nuclear power plants could fully displace the world’s fossil fuel electricity generation within three decades. Clearly all we lack is the political will.

Well, let’s look at some basic facts. Nuclear energy is dead in half of Europe, legally dead that is.

Germany, Italy, Belgium, Austria, Switzerland et al. will not be replacing their fossil fuel electricity generation with nuclear power plants in the next three decades. Neither will Japan. Neither will Australia, where nuclear energy is still illegal. We may, rightly, argue that climate change is a much bigger threat than the risks from nuclear power plants. In the eyes of vast numbers of people nuclear power plants are one of history’s great evils. This nonsense, coming from such misguided individuals as E.F. Schumacher, may die off eventually, but there are no signs that this death is imminent.

Meanwhile, aesthetic reactionaries and NIMBYs are doing what they can to stop onshore wind farms. The new British government effectively wants to block all new onshore wind farms. They would be happier with the landscape being blighted by ghastly neo-Georgian towns erected by Prince Charles than anything that looks as if it built after the age of Edison. Laws are now being erected in countries such as France, or regions like Bavarian, which will put strict restrictions on where wind farms can be placed. Destroying the planet to protect a view.

Clearly all we lack is the political will.

China, of course, is proving us pessimists wrong. Peak coal has been reached in China. 2 degrees is back on the cards.So we now hear.

Well, right now China has over 100 GW of coal power plants under construction. And it is gearing up to build at least double that when those plants are completed. If you believe coal is peaking in China, I have a bridge to sell you.

David Roberts of Vox, a man don’t often agree with, put it correctly:

The obvious truth about global warming is this: barring miracles, humanity is in for some awful shit.

I will be back tomorrow with some good news.

Plotting Californian renewables data using ggplot2

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I will be writing a couple of posts in the next month on solar and wind in California. But in advance of that I will write something on how to access and plot wind and solar data for California in R. Read the rest of this entry »

WordPress is playing up

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Something is currently going wrong with the scheduling on the blog. Damned if I know why it’s happening.

Stuff I’m scheduling is not going out on time, and a post I had written one line for just got published prematurely without me scheduling it.

I’ll investigate or complain to WordPress.

What we really need to know about public attitudes to wind farms

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A couple of simple questions:

1. Do you support the existence of motorways?

2. Do you support the existence of railways?

99.999% of people will say yes to both questions, at least I guess they would.

Now. Here is another question.

Would you like to live beside a motorway or a railway?

Suddenly I’m not sure if 99.999% of people will answer yes. In fact, I’m confident the majority would say no.

Let’s try another one.

Do you support onshore wind farms?

Read the rest of this entry »

Renewables pay you to take their electricity

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From The Age today:

Germany, the world leader in installing renewable energy, had a moment last month. It was producing so much electricity from solar, wind and biomass that more than half of the country’s electricity was flowing from these renewable sources.

There was so much, in fact, that the price of electricity actually fell to zero. And the price kept falling. It went negative. There were times on April 17 when wholesale electricity in Germany was selling for minus 14.91 euros for a megawatt hour. So it wasn’t free – it was cheaper than free.

Now, I’m not overly knowledgeable about economics and that kind of thing, so bare with me here. But is negative pricing for your product not a bad thing? Do the above facts not simply show that on April 17th Germany’s renewable energy plants were simply producing a lot of electricity which has more or less no market value?

I don’t think this is an overly complex point. Yet, occasional negative pricing is put forward as a positive for renewables. Can someone explain to me how it is not a negative?

If a Rome street vendor is standing around the Trevi Fountain trying to hawk umbrellas on a balmy August evening, the fact that tourists aren’t willing to give him a dime for them is not evidence umbrellas are cheap.

Meaningless energy unit of the day: cups of tea

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To make an issue understandable to the average person we do not use scientific units. This would simply confuse the average bone headed human. No, we must do what we can to condescend, and use units people are familiar with.

It’s difficult for someone to visualize what a tonne of coal looks like. Instead it would be much wiser if we told people what the weight of a few million tonnes of coal would be in terms of blue whales, as the Guardian did recently.

Confused by the meaning of the blue whale unit? Read the rest of this entry »