地球温暖化を2度Cに制限するための温室効果ガス排出目標
Malte Meinshausen1, Nicolai Meinshausen, William Hare
1Potsdam Institute for Climate Impact Research, Telegraphenberg, 14412 Potsdam, Germany. malte.meinshausen@pik-potsdam.de
Nature
|May 2, 2009
まとめ
地球温暖化緩和の取り組みは,温暖化を2°Cに制限することを目指しています. この研究では,2000~2050年の温室効果ガス (GHG) 排出予算を定量化し,気候変動政策に不可欠なデータを提供しています.
科学分野:
- 気候科学 気候科学
- 環境科学 環境科学
- 地球システム科学 地球システム科学
背景:
- 100カ国以上では,工業化以前のレベルと比較して2°Cの地球温暖化限界を目標としています.
- この温暖化限界に関連した温室効果ガス (GHG) の排出は,炭素循環と気候反応の変動性のために不確実です.
研究 の 目的:
- 2000年から2050年までの温室効果ガス排出予算の確率分析を行う.
- 21世紀の温暖化を2°C以下に制限する排出経路を定量化する.
主な方法:
- 気候システム特性の公開分布を利用した.
- 総合的な確率分析のための観察的制約を組み込みました.
- 累積CO2排出量と2050年の排出量レベルを指標として分析した.
主要な成果:
- 累積的なCO2排出量を2050年までに1,000GtCO2に制限すると,2°Cの温暖化を上回る確率は25%になる.
- 2050年までに1,440GtのCO2の限界値は,2°Cの温暖化を上回る50%の確率に相当する.
- 2050年までに世界の温室効果ガス排出量を半分に削減する (G8公告) は,2°Cを超える確率が12~45%である.
結論:
- 累積的な排出量と2050年の排出量は,温暖化を2°Cに制限するための強力な指標です.
- 2°Cの限界内に留まっても排出される可能性のある重要な化石燃料の埋蔵が残っています.
- 2020年の排出量は,2°Cを超える可能性に大きく影響するので,緊急に排出量削減が必要である.
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