Over on the Long Now blog a few weeks ago Stewart Brand posted some climate change calculations taken from a talk by Saul Griffith.
The aim of the calculations is to work out what needs to be done about climate change:
What would it take to level off the carbon dioxide in the atmosphere at 450 parts per million (ppm)? That level supposedly would keep global warming just barely manageable at an increase of 2 degrees Celsius. There still would be massive loss of species, 100 million climate refugees, and other major stresses. The carbon dioxide level right now is 385 ppm, rising fast. Before industrialization it was 296 ppm. America’s leading climatologist, James Hanson, says we must lower the carbon dioxide level to 350 ppm if we want to keep the world we evolved in.
The conclusions are in line with my understanding of the current best guesses of climatology in general:
The world currently runs on about 16 terawatts (trillion watts) of energy, most of it burning fossil fuels. To level off at 450 ppm of carbon dioxide, we will have to reduce the fossil fuel burning to 3 terawatts and produce all the rest with renewable energy, and we have to do it in 25 years or it’s too late. Currently about half a terrawatt comes from clean hydropower and one terrawatt from clean nuclear. That leaves 11.5 terawatts to generate from new clean sources.
He calculates the level of new power plant production using mixed technologies to replace those 11.5 terawatts of power:
- 2tw Photovoltaic: 1200 square miles of solar cells per year.
- 2tw Solar thermal: 600 square miles a year.
- ½tw Biofuels: 15,250 square miles of algae a year.
- 2tw Wind: 105,000 turbines a year.
- 2tw Geothermal: 1,095 steam turbines a year.
- 3tw Nuclear: A 156 nuclear power plants a year.
And we’d have to do all of these together every year for the next 25 years. And this only gets us to the 450ppm value, where there’s still a lot of stress, massive movements of climate refugees etc. The land area of all of these measures together is around the size of Australia, devoted entirely to renewable energy. If we did it all with nuclear, which is right now the most plausible option, we’d need to build around 600 nuclear power plants per year, and we’d end up with 15,000 plants.
Meanwhile we need to stay at 16 terawatts total energy consumption worldwide. That means that as the poorest parts of the world increase their energy consumption, the rest of us need to reduce ours. That means pretty much everyone in the rich world needs to stop flying, throw away their car, stop eating meat and stop buying stuff.
Being realistic for a second: what do you think the chances are that this is all going to happen? As a species do we have the will and the ability to build 600 nuclear plants a year and throw out all our cars and become vegetarians?
Apologies to those who think we’re somehow optimally made in the image of God, but we blatantly are not. We have proved only just smart enough to master agriculture - and that’s smart enough to have delivered the technological improvements we see around us. But as a group we’re barely able to cooperate enough to run an economy that functions.
I am becoming increasingly pessimistic about our potential to meet this potential extinction threat as a species, and the more data that comes in about climate change, the scarier it gets.
So, answers on a postcard please, where should I plan to live when in 25 years the world is 4 degrees hotter?
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