We have to stop building polluting infrastructure, now. Photo: eutorphication & hypoxia via flickr.
If you think all the carbon-spewing stuff we've built to date, from power plants to cars to airplanes, will just drag us over the climate change tipping point, think again. A new study, published in the journal Science, by scientists at the Carnegie Institution for Science's Department of Global Ecology shows that there is still sufficient time (just) to transition to cleaner technologies. Steven Davis describes the motivation for the project: "The problem with climate change is tremendous inertia. Some of this inertia relates to the natural carbon cycle, but there is also inertia in the manmade infrastructure that emits CO2 and other greenhouse gases. We asked a hypothetical question: What if we never built another CO2-emitting device, but the ones already in existence lived out their normal lives?"
What Davis and Ken Caldeira found was that if our existing stuff lived out its normal useful life (say 40 years for a coal-fired power plant, or 17 years for a modern car), between the years 2010 and 2060 the total projected emissions would be an additional 500 billion tons sent into the atmosphere. This, they say will result in atmospheric CO2 concentrations stabilizing below 430ppm and an increase on global mean temperature increase of less than 1.3°C.
This graph shows projected decline of carbon dioxide emissions in gigatons (billions of tons) from existing energy and transportation infrastructure (red wedge) over the next 50 years, compared to three emissions scenarios (dotted lines) from the Special Report on Emissions Scenarios Intergovernmental Panel on Climate Change. High, middle, and low emissions projections correspond to the SRES A1G-FI, A2, and B1 scenarios, respectively. Image and caption: Carnegie Institution
Graph shows projected decline of carbon dioxide emissions in gigatons (billions of tons) from existing energy and transportation infrastructure (multicolored wedge) over the next 50 years, compared to three emissions scenarios (dotted lines) from the Special Report on Emissions Scenarios (SRES) Intergovernmental Panel on Climate Change (IPCC). Colors within the wedge indicate projected emissions by various countries and regions. Non energy emissions shown are global emissions projected under the SRES A2 scenario. High, middle, and low emissions projections correspond to the SRES A1G-FI, A2, and B1 scenarios, respectively. Image and caption: Carnegie Institution
We Must Deploy Low Carbon Technologies Now
Ignore the fact that many climate scientists now say that 350ppm is a better benchmark to use to ensure the worst impacts of climate change are not felt, requiring emissions dropping below current levels of about 390ppm, even if 450ppm is still discussed in international policy discussions. In either case, we still solidly have our work cut out for us.
Caldeira notes, "Because most of the threat from climate change will come from energy infrastructure we have yet to build, it is critically important that we build the right stuff now--that is, low carbon emission emission technologies ... we cannot be complacent just because we haven't yet reached a point of no return."
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