The impact the humans are having on Earth’s resources depends essentially on three factors; population size, the affluence of this population, and our technological efficiency. This simple equation, laid out by the Stanford professor Paul Ehrlich nearly 40 years ago, makes for pretty scary math in 2010.

Carbon dioxide emissions make a good proxy for the rate at which we are using our planet’s resources. If, as the IPCC is calling for, we aim to stabilize atmospheric carbon dioxide at 450 parts per million by 2050, this means reducing our total carbon dioxide emissions by at least 4.9% per year between now and 2050.

However, affluence and global population are both growing, and appear very unlikely to do anything else between now and 2050 – what government could deliberately limit the affluence of its citizens? This means that the burden of reducing carbon dioxide emissions must fall on the efficiency with which we use the planet’s resources. Jackson let’s numbers tell the story of what this means:

But this calculation assumes the world remains a very unequal place – developed countries getting steadily richer, China and India getting rapidly richer, and most of the rest of the world remaining crushingly poor. If we are serious about equality and wanted all of those 9 billion people to enjoy prosperity similar to US citizens today, then our efficiency would need to improve to 14 grams of carbon dioxide per US dollar – 55 times more efficient than today.

And this still assumes no income growth in developed nations. If we want an equal world where on average US citizens still get a little richer by 2050, then we must improve efficiency to the point where only a measly 6 grams of carbon dioxide are needed for each US dollar – this is 130 times more efficient than today.

If we dare contemplate population and affluence continuing to grow beyond 2050, well then every dollar of economic activity must actually take carbon out of the atmosphere!

These simple numbers – no more than primary school arithmetic – speak a stark reminder of how we must use our planet’s finite resources a great deal more carefully than we currently are. A sustainable and equitable world means a very different one from that in which we currently live.

2 Comments on "Scary math"

Simon in BC on Fri, 17th Dec 2010 1:47 pm 



The only hope for the planet is a massive die off – of human beings. And that will probably occur due to drought, famine, flood, civil unrest and war, mainly in the poorest parts of the world, those least responsible for the damage we are doing to the Earth’s ecosystem. And all so that we, the wealthy can continue to live lives of profligate waste.

Kenz300 on Fri, 17th Dec 2010 10:21 pm 



Limited resources of food, water, oil, phosphorous, tuna and rare earth metals all have been in the news recently.

We have been unable to solve the worlds problems of poverty, hunger and disease when the world had 5 billion people and abundant resources. How will the world cope with 9 billion people and limited resources?

Both the rich and poor countries will suffer with higher prices and resource shortages.

Wars will be fought over limited resources. Man’s inhumanity to man will come forward when personal survival is at stake.

We need to develop sustainable communities that generate goods,services and jobs close to the point of consumption. Victory gardens anyone?
We also need to provide local sources of energy and jobs.

Wind, solar, geothermal and second generation biofuels all need to ramp up production. Our economic security and national security depend on it.