Some challenging discussions on this on the New Scientist website. Here’s an extract from an article by Tim Jackson
‘The Ehrlich equation, I = PAT, says simply that the impact (I) of human activity on the planet is the product of three factors: the size of the population (P), its level of affluence (A) expressed as income per person, and a technology factor (T), which is a measure of the impact on the planet associated with each dollar we spend.
Take climate change, for example. The global population is just under 7 billion and the average level of affluence is around $8000 per person. The T factor is just over 0.5 tonnes of carbon dioxide per thousand dollars of GDP – in other words, every $1000 worth of goods and services produced using today’s technology releases 0.5 tonnes of CO2 into the atmosphere. So today’s global CO2 emissions work out at 7 billion × 8 × 0.5 = 28 billion tonnes per year.
The Intergovernmental Panel on Climate Change (IPCC) has stated that to stabilise greenhouse gas levels in the atmosphere at a reasonably safe 450 parts per million, we need to reduce annual global CO2 emissions to less than 5 billion tonnes by 2050. With a global population of 9 billion thought inevitable by the middle of this century, that works out at an average carbon footprint of less than 0.6 tonnes per person – considerably lower than in India today. The conventional view is that we will achieve this by increasing energy efficiency and developing green technology without economic growth taking a serious hit. Can this really work?
With today’s global income, achieving the necessary carbon footprint would mean getting the T factor for CO2 down to 0.1 tonnes of CO2 per thousand US dollars – a fivefold improvement. While that is no walk in the park, it is probably doable with state-of-the-art technology and a robust policy commitment. There is one big thing missing from this picture, however: economic growth. Factor it in, and the idea that technological ingenuity can save us from climate disaster looks an awful lot more challenging.
First, let us suppose that the world economy carries on as usual. GDP per capita will grow at a steady 2 or 3 per cent per year in developed countries, while the rest of the world tries to catch up – China and India leaping ahead at 5 to 10 per cent per year, at least for a while, with Africa languishing in the doldrums for decades to come. In this (deeply inequitable) world, to meet the IPCC target we would have to push the carbon content of consumption down to less than 0.03 tonnes for every thousand US dollars spent – a daunting 11-fold reduction on the current western European average.
Now, let’s suppose we are serious about eradicating global poverty. Imagine a world whose 9 billion people can all aspire to a level of income compatible with a 2.5 per cent growth in European income between now and 2050. In this scenario, the carbon content of economic output must be reduced to just 2 per cent of the best currently achieved anywhere in the European Union.
In short, if we insist on growing the economy endlessly, then we will have to reduce the carbon intensity of our spending to a tiny fraction of what it is now. If growth is to continue beyond 2050, so must improvements in efficiency. Growth at 2.5 per cent per year from 2050 to the end of the century would more than triple the global economy beyond the 2050 level, requiring almost complete decarbonisation of every last dollar.
The potential for technological improvements, renewable energy, carbon sequestration and, ultimately perhaps, a hydrogen-based economy has not been exhausted. But what politicians will not admit is that we have no idea if such a radical transformation is even possible, or if so what it would look like. Where will the investment and resources come from? Where will the wastes and the emissions go? What might it feel like to live in a world with 10 times as much economic activity as we have today?’
This underlines the presence of taboos in policy debate. To avoid catastrophic climate change, we either have to massively improve the carbon efficiency of growth, or we have to accept less or even negative growth. Unfortunately, since about 2000, the carbon efficiency of growth has been falling. Yet the ‘limits to growth’ discussion is off limits with policy makers, who not unreasonably see it as political suicide (I feel anxious even writing about it here). Why? Not only do recessions lose elections, but reforms are far harder in a stagnant or declining economy – when the pie is shrinking, people get more defensive and cling to what they have. Major shocks (like the Great Depression) or growing economies seem to be more propitious to change. Big problem.
For another thought provoking New Scientist portrait of a zero growth world in which ‘scientists set the rules’ (speaking as a lapsed scientist, a truly alarming prospect), see here.