Of course Vaclav Smil is correct that Moore’s Law-type growth rates of 35 per cent per year will not go on forever, however astonishing the record so far (“Infinite growth is a pipe dream”, August 9). But how about 2 per cent? Professor Smil turns up his nose at a growth rate of a mere 2 per cent real per capita per year. Yet that very 2 per cent continued over long times is the true miracle that has created the modern world. At 2 per cent compounded, in a century, people are on average seven times economically better off. So we ordinary people are seven times better off than our ancestors were as Woodrow Wilson et al negotiated the Treaty of Versailles in 1919.

This is amazing. Can we imagine that people in 2119 will again be on average seven times better off that we are today? That would be the result of the golden 2 per cent. Whether 2 per cent can continue indefinitely is a far more interesting question than whether 35 per cent can.