This graph shows the 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 (SRES) Intergovernmental Panel on Climate Change (IPCC). High, middle, and low emissions projections correspond to the SRES A1G-FI, A2, and B1 scenarios, respectively. Image courtesy of Stephen J. Davis
A dead stop on building CO2 emitting devices would be enough to avoid dangerous climate change, scientists have claimed in top journal Science this week. However, the world is so committed to using fossil fuels to provide energy, the Carnegie Institution’s Steven Davis says it will be difficult to avoid directly replacing existing emitters. “CO2 emitting infrastructure will expand unless extraordinary efforts are undertaken to develop alternatives,” Davis and his colleagues write.
Energy generation and transportation will emit around 496 billion tonnes of CO2 over the next 50 years, Davis, his Carnegie colleague Ken Caldeira, and Damon Matthews of Concordia University in Montreal calculated. That would increase atmospheric CO2 concentrations from 385 parts per million (ppm), which itself is a big rise from around 280 ppm in pre-industrial times, but the increase would stop at around 430 ppm. This is below the 450 ppm level that’s widely accepted will cause a dangerous 2°C temperature increase from pre-industrial averages
. Davis and colleagues predict the average global temperature rise in this scenario would be about 1.3°C. “The answer surprised us,” said
Davis. “Going into this study, we thought that existing sources of CO2 emissions would be enough to push us beyond 450 ppm and 2°C warming.” Read the rest of this entry »