My first blog in June 2009 was an In Memoriam piece dedicated to Alan Rundle, one of my first bosses, who had helped me enormously with my career development. Sadly he had died of a heart attack while participating in a marathon. I have since published 25 more In Memoriam pieces, mostly about people I have both known well and admired, though a few have been about extraordinary people like Winston Churchill and Martin Luther King even though I did not know them personally.

Of the people I’ve known personally, I usually write them soon after I have learned of their passing. Professor David MacKay died of cancer at the age of 48 in 2016. But that year I was Master of the Worshipful Company of Marketors and every blog I published covered my experiences in that role. I wrote three In Memoriam blogs that year about notable Past Masters who had recently died.

But the current crisis re the coronavirus and its likely effect on the health of the population and the economic challenges it poses, together with the continuing crisis of global warming and climate change have reminded me of Professor Mackay and his unique contribution to the debate about sustainability.

I first met David at the Department for Transport. He was then Professor of Physics at Cambridge University. I was then Chairman of innovITS, a centre of excellence backed by the automotive industry to promote Intelligent Transport Systems and funded by the then Department for Business, Enterprise and Regulatory Reform (DBERR, now BEIS) Innovation and Skills. David gave a talk to an invited audience on energy and more specifically electric vehicles. I asked him how many vehicles could be built with lithium ion batteries given known resources of lithium. He thought it would be about a billion and afterwards we developed the conversation and really hit it off.

In 2008 David had a publishing phenomenon with his book Sustainable Energy: Without the Hot Air. He financed the initial publication himself but also made it available for free download. [i] The Economist reviewed it as a “tour de force” and Bill Gates praised it as “one of the best books on energy that has been written.”  David was motivated to write the book as he was distressed by the poor quality of the debate surrounding energy. Politicians and big business were guilty of greenwash while campaigners were naïve in their numerical assumptions. 

David’s style was to present his detailed analysis, not to take sides in the argument but to help the readers reach their own conclusions. An alternative working title for the book had been “You Figure It Out”. The book’s masterstroke is to express all forms of power consumption and production, - the car, the washing machine, the wind turbine, the mobile phone charger, the nuclear power station – in a single unit of measurement. Rather than bamboozling the reader with terawatts, gigahertz and joules, he simply uses the kilowatt hour per day (kWh/d) roughly one 40-watt lightbulb left on for a day - to compare energy consumption of everything from solar power to air travel.

Thus driving the average car 50km a day consumes 40k Wh/d, i.e. the equivalent of 40 40W lightbulbs constantly lit for a day. The beauty of this is it can be used to debunk many of the myths that had built up around energy consumption and alternative energy sources. David was irritated by those who particularly criticised the excessive use of mobile phone chargers. “The amount of energy saved by switching off the phone charger is exactly the same as the energy used by driving an average car for one second”

David wrote the book in 2006 and many of the numbers he presented are out of date, partly because of his own work. At that time he reported that the developed world got 80% of its energy from fossil fuels; Britain 90%. But in 2019 The National Grid reported that more of the UK’s electricity came from clean sources than fossil fuels for the first time. Fossil fuels accounted for only 43% of the energy used with coal at only 2.1%. 48.5% came from sources such as wind farms, hydro plants, solar and nuclear energy and clean power imported through subsea cables. The remaining 8.5% came from biomass, which is renewable but is polluting when it is burnt for energy. In 1990, coal accounted for 75% while zero-carbon renewables such as wind, solar and hydro have gone from 2.3% in 1990 to 26.5% in 2019.

David was first appointed a Cambridge University professor of physics at the unprecedentedly young age of 36 in 2003. He was a true polymath and contributed to the advancement of several scientific frontiers. As well as his work on energy he made substantial achievements in information theory, machine learning and neural networks. In 1995 he showed that mathematical code could squeeze immense amounts of data reliably through noisy communication links. Known as low-density parity-check codes are now used in varied applications such as computer disk drives, digital broadcasting, mobile phone networks and Wi-Fi.

His interest in human-machine interfaces led to his invention in 1999 of Dasher, a keyboard-free text-inputting programme that uses a predictive language model allowing users to write efficiently using eye and head movements or even breathing. Dasher resembles a video game and is available in 100 languages. It has been downloaded 140,000 times, transforming the lives of many people with impaired mobility.

David’s mastery of probability theory helped right a notorious miscarriage of justice, when the solicitor Sally Clark was wrongly imprisoned in 1999, found guilty of murdering her two babies. A key witness for the prosecution had misused statistics to tell the court that there was only a 1 in 73m chance that Clark’s babies had died naturally in cot deaths. He recalculated the probability and proved that Clark was far more likely to be innocent than guilty. He helped a campaign for her release, which was achieved after a second appeal in 2003.

After the success of his book his unusually rational approach to finding solutions to apparently intractable problems brought him to the attention of government and in 2009 he was appointed chief scientific adviser to the Department of Energy and Climate Change (DECC).  He was a highly effective civil servant who convinced the then coalition government to publish a carbon plan in 2011 that drew directly on his numerate approach towards energy.  While at DECC, he also launched a “2050 calculator” that enabled anyone to choose between multiple options for achieving the UK’s mandated 80% carbon emission reductions by 2050.

While showing various options both in his book and in the work he did at DECC, David demonstrated that the choices of achieving these goals just by adopting cleaner sources of energy were improbable. There also needed to be significant reductions in the use of energy. He himself lived up to this. He refused to own a car for most of his life and his book includes graphs showing significant reductions in the energy consumption in his own house in Cambridge over many years. When visiting anyone’s house the first thing he would do is turn down the thermostats saying this was one of the biggest savings we could all make as individuals. In 2014 he returned to academic life and was appointed Regius professor of engineering at Cambridge. He was knighted in the New Year’s Honours in 2016 and died in April that year.

We could do with him now as we face such serious challenges when the proper understanding of statistical models has perhaps never been so important.

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