Knowledge for better food systems

Major cuts to surging CO2 emissions are needed now, not down the road

A perspective paper published by Environmental Research Letters revisits the 2004 study by Pacala and Socolow that deployed seven wedges of different existing energy technologies to address climate change. At the time of that paper’s publication, each wedge would avoid one billion tons of carbon (1 GtC) emissions per year after 50 years. In this new perspective paper, its authors show that as a result of increased emissions, merely achieving what was considered "business-as-usual" in 2004 would require the development and deployment of 12 wedges; stabilizing emissions at current levels would require another 9 wedges; decreasing emissions to the level needed to prevent climate change would need an additional 10 wedges. Altogether, 31 wedges would be required to stabilize the Earth's climate.

The authors conclude that filling this many wedges while sustaining global economic growth would mean deploying tens of terawatts of carbon-free energy in the next few decades, which would entail a fundamental and disruptive overhaul of the global energy system.

Stabilizing CO2 emissions at current levels for fifty years is not consistent with either an atmospheric CO2 concentration below 500 ppm or global temperature increases below 2 °C. Accepting these targets, solving the climate problem requires that emissions peak and decline in the next few decades, and ultimately fall to near zero. Phasing out emissions over 50 years could be achieved by deploying on the order of 19 'wedges', each of which ramps up linearly over a period of 50 years to ultimately avoid 1 GtC y−1 of CO2 emissions. But this level of mitigation will require affordable carbon-free energy systems to be deployed at the scale of tens of terawatts. Any hope for such fundamental and disruptive transformation of the global energy system depends upon coordinated efforts to innovate, plan, and deploy new transportation and energy systems that can provide affordable energy at this scale without emitting CO2 to the atmosphere.

Citation as follows:
Davis, S.J., et al. (2013). Rethinking wedges. Environmental Research Letters, 8. DOI: 10.1088/1748-9326/8/1/011001

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For an article on the perspective, click here.

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While some of the food system challenges facing humanity are local, in an interconnected world, adopting a global perspective is essential. Many environmental issues, such as climate change, need supranational commitments and action to be addressed effectively. Due to ever increasing global trade flows, prices of commodities are connected through space; a drought in Romania may thus increase the price of wheat in Zimbabwe.

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