エネルギーの自給を追求しても気候変動を緩和できない

Although cutting carbon emissions can lead to energy security benefits, such as reducing energy imports, pursuing energy independence will not equivalently reduce emissions, reports a paper published online this week in Nature Energy. The analysis of the links between energy security and climate change policies highlights that emissions reductions targets are unlikely to be achieved by solely seeking policies that make nations more energy-independent.

Energy security is frequently considered to be a co-benefit of pursuing climate change mitigation policies. The opposite - that pursuing energy security can bring about reductions in greenhouse gas emissions - is often claimed to be true as well.

Jessica Jewell and colleagues employ a series of state-of-the-art global energy-economy models to assess the impact of energy independence policies on emissions, the likely changes that energy independence or climate policies will have on the energy system, and the comparative costs of implementing either. They find that combatting climate change will lead to lower energy imports, but that ensuring energy independence will lead to only modest (2-15%) cuts in greenhouse gas emissions. They also show that constraining energy imports would cut fossil fuel use and energy demand, but may not universally increase the use of renewables.

Finally, the authors show that energy independence could be achieved at a comparable cost to meeting existing emissions reductions pledges, but at a fraction of the cost of limiting global warming to 2 °C. They conclude that more careful analysis of the relative costs of different policy objectives is required when the likely co-benefits of climate policies are discussed.

In an accompanying News & Views article, Vaibhav Chaturvedi writes: "The study by Jewell and colleagues is a very useful contribution to understanding the balancing act between pursuing climate policy goals and securing energy supply."