要幫助發展中國家針對氣候變遷進行調適（adaptation），全世界必須付出的經濟代價約在每年750至1000億美元之間。
這份數據來自世界銀行1日發布的《氣候變遷調適經濟學》報告，這是由荷蘭、瑞士與英國政府所贊助、目前為止針對氣候變遷調適議題分析最為深入的經濟學報告。報告發表的場合，正是聯合國在曼谷展開的2012年後溫室氣體減量談判會議。
這份報告也首度針對調適代價提出了可行的定義，詳細說明調適的具體內容、發展所扮演的角色、以及必要的政策調整方向。
該報告指出，假定一國面對氣候變遷的脆弱程度隨著經濟成長而遞減，那麼調適的佔GDP（國內生產毛額）的百分比將逐漸減少。世銀環境部主任伊凡（Warren Evans）表示，「經濟成長是最有力的調適類型，然而，不能再是往常的經濟成長模式。儘管調適能減輕氣候變遷的衝擊，卻仍未針對問題的原因，要少災害風險，減緩氣候變遷仍是無可替代的方案。」
該報告用新的方法來評估調適代價，比較「發生氣候變遷的世界」與「未發生氣候變遷的世界」兩種情境。兩個世界的差異，即表示調適所必須實施的行動，實施這些額外行動所負擔的代價，即代表調適的代價。
整份報告中很重要的一部份是，針對兩種氣候變化情境──潮濕或乾旱，評估了主要經濟部門所必須付出的代價。
在乾旱情境下，每年代價是750億美元，潮濕情境下，則高達1000億美元。除了南亞以外的其他地區，乾旱情境的調適代價均比潮濕情境為低。
調適代價最高的地區則分別是東亞－太平洋地區、拉丁美洲暨加勒比海國家、以及非洲撒哈拉以南。
荷蘭發展合作部長昆德斯（Bert Koenders）表示，「世銀報告清楚顯示，針對調適採取行動，可替未來省下經費並減少不可接受的風險。由富裕國家的GDP來看，國際社群仍能承受調適的代價，但這代價對貧窮國家來說可是天價……要幫助貧窮國家更能因應氣候變遷，減緩暖化、調適與發展合作是必須的。特別是國際財務援助要重新調整並擴大，以免危及『千禧年發展目標』（Millennium Development Goals）。」
Helping developing countries adapt to climate change will cost the world between US$75 and $100 billion per year for the period 2010 to 2050, the World Bank said today. The figures are detailed in the most in-depth analysis of the economics of climate change adaptation published to date.
The draft consultation document was released at ongoing United Nations climate negotiations in Bangkok that are shaping a post-Kyoto Protocol greenhouse gas agreement to take effect at the end of 2012.
The study, "Economics of Adaptation to Climate Change," funded by the governments of the Netherlands, Switzerland, and the United Kingdom, is
This is the first report to develop a workable definition of adaptation costs that can set the stage for common understanding of what adaptation actually entails, what role development plays, and what policy changes are needed to facilitate adaptation.
Suggesting that countries become less vulnerable to climate change as their economies grow, the study finds that adaptation costs decline as a percentage of GDP over time.
"Economic growth is the most powerful form of adaptation," said Warren Evans, director of the World Bank’s Environment Department. "However, it cannot be business as usual. Adaptation minimizes the impacts of climate change, but it does not address its causes. There is no substitute for mitigation to reduce catastrophic risks."
The study uses a new methodology for assessing these adaptation costs, comparing a future world without climate change and a future world with climate change.
The difference between these two worlds entails a series of actions to adapt to the new world conditions. The costs of these additional actions are the costs of adapting to climate change.
A key part of the overall analysis involved estimating adaptation costs for major economic sectors under two alternative future climate scenarios, a wet scenario and a dry one.
Under the dryer scenario, the adaptation cost is estimated at US$75 billion per year, while under the scenario that assumes a wetter future climate it is US$100 billion. The drier scenario requires lower adaptation costs in all regions except South Asia.
The highest costs of adaptation will be borne by the East Asia and Pacific Region, the World Bank reports, followed by Latin America and the Caribbean, and Sub-Saharan Africa.
"The World Bank study makes plain that taking action in favor of adaptation now can result in future savings and reduce unacceptable risks," said Dutch Minister for Development Cooperation Bert Koenders.
"At this point," Koenders said, "the costs this will entail can still be borne by the international community, to judge by the GDPs of rich countries, but for poor countries they are unacceptably high."
"More than ever, mitigation, adaptation and development cooperation are needed to make the poor less vulnerable to climate change," he said. "International public financial support for adaptation in the poorest developing countries should be new and additional, so as not to jeopardize the Millennium Development Goals."
全文及圖片詳見：ENS
