報告書番号

Y09007

タイトル（和文）

ボトムアップアプローチによるポスト京都議定書の国際枠組み

タイトル（英文）

The Bottom-up Approach for Post-2012 International Climate Change Agreement

概要 （図表や脚注は「報告書全文」に掲載しております）

本稿では、日本では理解あまり概念があまり浸透していないボトムアップアプローチについて、これまでの議論の系譜を辿りながら、①国内政策が起点、②結果よりも行動、③行動実施の国際レビューという3つの主要な要素を解説した。その上で、現時点での状況理解に基づいて、「コペンハーゲン合意の発展」として捉えられるボトムアップアプローチと、「京都議定書の延長」として捉えられるトップダウンアプローチを、①環境への効果、②一定の環境効果を実現する際の費用対効果、③新たな情報に対応する柔軟性、④参加国の範囲という4つの基準から定性的に比較し、前者のほうが望ましいと評価した。ただし、この評価は状況依存的であり、時間が経過し、状況が変われば、結論も変わりうる。

概要 （英文）

This report examines with a bottom-up approach for post-2012 international climate change agreement. Historically, the Kyoto Protocol follows a top-down approach in a sense that countries agreed on international emissions targets for developed countries at first and then respective countries implement domestic policies to meet their targets. By contrast, in a bottom-up approach, countries domestically determine their policies and measures to control emissions at first at their discretion and then place their actions at an international framework for the purpose of international authoraization. Reviewing research literature and policy proposals by countries, the author identifies three features of the bottom-up approach, in comparison to the Kyoto Protocol. First, domestic policy and measures adopted by respective countries replace internationally-negotiated targets. This reflects the current situation that countries are likely to implement their policies and measures based on domestic laws despite little clarity on international framework after 2013. Second, commitments to actions replace commitments to results such as maximum emissions at a certain target year. Finally, implementation of actions countries commit to is internationally reviewed by experts and other countries. Unlike the Kyoto Protocol which penalizes non-compliance countries, this approach aims to facilitate further efforts by countries by increasing transparency through international review. Considering the fact that the Copenhagen Accord that was taken note of by COP15 in 2009 basically follows a bottom-up approach, this report then compares the Accord with the possible extension of the Kyoto Protocol after 2013, in terms of environmental effectiveness, cost-effectiveness, responses to new information, and participation and compliance, and conclude that the former is likely to be advantageous, particularly in terms of the second and third criteria, although this assessment is subject to the future development of the Copenhagen Accord.

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