Why 80%?

• Author: Cox, Stan
• Position: 80% Less Energy - Report

When late last year the S/R editorial board decided to tackle the question of how to reduce the United States' energy consumption by 80%, it was the first time I had heard that figure. In the months since, however, I've been hearing "80%" from all kinds of sources. On April 14, for example, a national "Step it Up" event, encompassing more than 1400 actions across the country, called for an 80% reduction in US carbon emissions. But the relative contributions of energy reduction and renewable energy generation toward achieving that goal were left unspecified.

In many cases, it's not clear how people have arrived at the 80% figure (either for emissions or energy reduction), but various rough calculations based on global estimates from different sources all tend to point in that direction. Let's look first at the need for reductions in carbon emissions and then at how much less energy we'll have to use to achieve those reductions.

The 2005 Millennium Ecosystem Assessment, produced by more than 1360 experts worldwide working over a four-year period, concluded that 15 of the 24 key "services" that ecosystems provide to humanity are in decline because of human activity. Scientists responsible for the climate-change section of the report estimated that just to keep planet-wide temperatures from rising more than two degrees Celsius (that being a threshold beyond which research suggests that runaway heating will occur) will require that humanity's carbon emissions must begin to decline by around 2015 and be held to between 3 and 7 billion metric tons per year by 2050. [1] That would be about 800 to 1800 pounds per year per person worldwide.

The United States currently pumps out about 12,000 pounds of carbon per person. Therefore, if Americans are to be good global citizens by 2050, we will have to slash current per capita emissions by 85 to 93%. But the US population is expected to grow from 300 to 400 million by 2050, so those cuts will have to be 88 to 95%. In his 2006 book Heat: How to Stop the Planet from Burning, George Monbiot concludes that emissions will need to be cut even more deeply and rapidly, to 725 pounds per person by 2030. That would mean reductions of 90% across the wealthy world, reaching 87% in the UK and 94% in Australia and the US within a quarter-century. [2] Monbiot's may be a worst-case scenario, but in highly unstable situations like the one we face, reality usually ends up at the worst case or beyond.

Analyses based on...