Don’t mention the solar panels

On a flight this morning I began to think that the Bjorn Lomborg quote I heard yesterday couldn’t be plausible:

Germany once prided itself on being the “photovoltaic world champion”, doling out generous subsidies – totaling more than $130 billion to citizens to invest in solar energy…by the end of the century, this will have postponed climate change temperature increases by 23 hours.

So I tried a quick back of the envelope calculation:

German population = 70m

Global population = 7bn

Ratio = 1/100

Number of years solar panels last for = 20

Years over which CO2 emissions have and will accumulate before the bad temperature rise (say 2100 – 1900) = 200

Ratio = 1/10

Reduction in CO2 emissions of Germany = 1/100 (the article gives a less than 1% current total supply by solar)

Germany’s level of emissions during these 20 periods relative to global average over 200 years = x2

Total portion of CO2 from global total that will be avoided =(1/100) x (1/10) x (1/100) x 2 = 2/100,000

Number of days over which CO2 emissions occur = 365 * 200 = 70,000ish

Over 1m Germans have solar panels installed. Number of days of CO2 emissions avoided from these, i.e., how much extra time is bought before a catastrophic temperature increase  = 70,000 x 2 / 100,000 = 1.4 days

Wow. Well done. I definitely feel less bad about my flight now. Not that I was.

I came across Without Hot Air several years ago and found it to be very credible – same approach, back of the envelope physics…I seem to have just complimented myself on being very credible. I’d best stop myself here. It’s not impossible I’ve missed something obvious out of the above…


Sentences of note

Things I read / heard this week:


Germany once prided itself on being the “photovoltaic world champion”, doling out generous subsidies – totaling more than $130 billion to citizens to invest in solar energy…by the end of the century, this will have postponed climate change temperature increases by 23 hours.

Source: Bjorn Lomborg


“If I was Saddam Hussein and I really wanted to make a virulent flu virus, I would take a recently drawn flu virus, I would passage it through groups of 20 prisoners, I’d take the virus from the ones who were dying, and I would passage it through more. Anyone could do this. You just have to be unscrupulous enough.”

Source: Peter Doherty


People pay more attention to the number killed in a natural disaster than to the number of survivors when deciding how much money to donate (estimated at $9,300 per person killed). The number of people affected in the disasters, on the other hand, appeared to have no influence on the amount donated to relief effort

Source: Journal of the Association for Psychological Sciences

Zero waste, zero point

I attended a talk by Bea Johnson on ‘Simplifying Your Life’ this week. Her family has completely changed their lifestyle, e.g.,

…if your hair is short, you also have the “no-poo” option: rinse your hair, massage baking soda in, then rinse, with vinegar for shine

to reduce to virtually nothing the amount of household waste they generate that ends up in landfill.


This got me thinking…


It seems that the UK produces roughly 250 kg of landfill waste per person per year. Corroborated here.

Assume this is compacted to a volume with a density half that of water.

There are 25m households in the UK, with an average of 2.4 persons each.

This source says 33 sq m per person (which sounds about right given the above):

Household floor space per capita

With a ceiling height of 3.3m, this is 100 cubic metres of space per person.Which,

allowing for lifetimes of 100 years, the entire landfill waste generated by a household would occupy around half of the volume of the house.

OK, I’m probably off by a factor of 2 here and there, but this doesn’t seem to me to be so big an issue to need to solve so drastically, especially given that the amount of surface area covered by housing in the UK is quite small anyway.

Nuclear power deaths

A recent paper from NASA seeks to analyse total global fatalities attributable to nuclear power.

They find that 1.8 million deaths have been AVOIDED over the lifetime of the nuclear power industry due to a reduction in air-pollution related diseases that would have resulted from fossil fuel burning.

A few more notes on nuclear power here.

Half in, half out

More people live inside this area than live outside:

Half worlds population

You might also like this graphic of population density.


Over 98% of expert games begin with 1 of 4 moves, out of a possible 20:


I used to play the Grob (1.g4) and did quite well with it. It’s a trade off, making a slightly less good first move to very quickly get into positions that your opponent has never been in before and needs to use up clock time to consider options from an unusually early stage of the game.

This is a tactic that Kasparov used against IBM’s Deep Blue, reaching a position after 3 moves that had only ever been seen once before at tournament level.

in any long game of chess it’s quite likely that a position is reached that no two players in the history of humanity have encountered before.

More in Nate Silver’s ‘The Signal and the Noise’.

Football is not a matter of life and death

I attended a lecture this week on research between stress and heart attacks, where this chart (from a New England Journal of Medicine paper) was displayed, showing incidences of heart attacks in the German population over the period of the 2006 Football World Cup, along with the data for previous years for comparison:

Show me the numbers

No really, show me the numbers. That was too fast…here’s a clip from a competition where people are adding together 15 3-digit numbers:



The world record is 1.70 seconds. Mental images of abacuses are the key.

More here.

Heads I win, tails you lose

In an article by Tim Harford, it was reported that only 25% of Labour MPs were able to correctly answer the question “what is the probability of getting two heads when a coin is tossed twice?”
For comparison, 30% of the general population got the question right.


Today I went to a ‘bite-sized lunchtime lecture’ at UCL, and courtesy of Dr Sara Hillman learnt that a low birth weight child was a predictor of future diabetes in the father, and that in turn having a father who smoked was a predictor of the baby being born with a low birth weight.

And then across the road at the Wellcome Trust had a look at a set of books mapping all 23 chromosomes containing the complete human DNA sequence:


There are 3 billion letters in the books, and if you compared your own DNA to the sample in the book you’d find only a few million differences