John Shepherd on Science and Climate Change

Let’s start with your first book, Fixing Climate: The Story of Climate Science – and How to Stop Global Warming by Robert Kunzig and Wallace S Broecker.

One of the reasons for picking this book is that Wally Broecker is my guru. He has been a friend for nearly 40 years and is a big influence on my life. This book is partly the story of his scientific development through the years, starting from a geochemist working in a lab to being one of the most influential people working in the world on oceanography and climate change. I think Robert Kunzig did most of the actual writing based on talking to and following Wally while he was doing his work.

And what kind of hope does he offer for the climate crisis?

What he is saying is that we could and should remove carbon dioxide from the atmosphere, having put it there without realising what the consequences would be. He suggests (credibly in my view) that it is possible to remove it and that we need to find ways of doing that in order to restore the climate to something closer to a natural state.

In the context of climate change there are two main things that science can help us to do which are reflected in the books I have chosen. One is what you might call Plan A, which is how to find low carbon sources of energy and reduce our energy consumption, and the other is Plan B, the geoengineering idea to intervene directly to modify climate if we can’t achieve enough with Plan A.

But does he have any ideas about how he thinks it can be done?

Yes, because a colleague of his is someone called Klaus Lackner who is developing a rather clever method for removing CO2 from the air without using too much energy. There are lots of different ways of removing CO2, but the trick is finding a way to do it in a closed cycle, without using more energy than you generated in the first place, and so doing more harm than good in the process.

Your next book is Factor Four: Doubling Wealth, Halving Resource Use by Ernst von Weizsacker, Amory B Lovins and L Hunter Lovins.

This is an inspirational book written quite some years back. It was really saying that we don’t have to go back to living in stone caves and wearing hair shirts in order to sort this problem. If we use our intelligence we could achieve this factor four, which is expressed as doubling wealth and halving resources. And that is quite an appealing message.

Amory Lovins was one of the best known environmentalists and at the time most of them were saying that we must do less of this and less of that. But he was saying that if we use technology intelligently we don’t have to be poor again. We could still maintain the lifestyle to which we all aspire.

And do you think that is just wishful thinking?

There is some wishful thinking in the book I am sure. But it is possible. The main problem is the carbon dioxide issue is a lot bigger than a factor of four. I have a lecture that I give on climate change which suggests that it is a factor of 40, which is a derivation from the title of this book. What I mean by that is that we need to reduce carbon dioxide emissions by about 75 per cent by the end of the century or maybe a bit sooner.

At the same time the world’s population is probably going to double which makes it worse. And the developing world is liable to use more energy rather than less. If the bulk of the developing world only comes up to the level of Europe (let alone North America) that is another factor of five.

So I multiply four by two, then by five, and come up with 40 as the amount by which we have to reduce the amount of carbon we use to produce one unit of GDP. So factor four gets us some of the way but not all of it.

Your next book, Sustainable Energy – Without the Hot Air, by David J C MacKay, is called ‘the must-have book for anyone who is seriously interested in energy policy’. Is that the case?

Well, this is a very interesting book by a very interesting person. David Mackay is a professor of physics at Cambridge, but is also now the chief scientific advisor at the Department of Energy and Climate Change. So he is very influential. Before he had that appointment he wrote this book, which really tries to put things in context. He does very simple sums, back-of-the-envelope sums, as to how much energy could we get from bio-fuels, how much energy could we get from wind power, how much land would it take? He looks at all these scenarios that you hear talked about, and his conclusion is that they can make a significant contribution but it is basically not going to solve the problem. We are probably going to need additional things like carbon capture and nuclear energy to help fill the gap.