我很高興能和環保署一起舉辦今天(11月3日)的記者會，這顯示我們雙方都非常重視史登報告所提出的議題。
這星期一 (10月30日)在倫敦公佈了一份由史登撰寫的「氣候變化的經濟學報告」，這是至今針對全球氣候變化最完整詳盡的報告。去年6月由英國財務大臣布朗委託尼古拉斯‧史登爵士撰寫，史登是政府經濟服務部門的負責人，也是世界銀行的前首席經濟學家。
這份報告顯示，氣候變化的科學證據已經無可反駁，報告中並包括氣候變化潛在影響的驚人數據。然而史登報告的結論基本上是樂觀的：只要立刻採取行動，我們還有時間阻止全球氣候變化造成更嚴重的後果。
史登報告的前半部份在闡述氣候變化如果不加控制將造成的嚴重影響和風險，和現在採取行動控制氣候變化的所需成本和可能機會。在過去幾世紀以來，我們所用的經濟模型並不能提供精確的預測，但卻是解釋氣候變化帶來影響範圍的重要方法。
全世界各個區域都將會被氣候變化所影響。台灣也不例外，特別是氣候變化可能帶來洪水或颱風模式改變。如果不採取行動，氣候變化將使得目前的平均氣溫比工業革命前要高出攝氏5度，這些變化將造成地球自然地理的改變，並影響人們在哪裏生活、以及如何生活。
根據2001年由氣候變化國際間審查小組所提出的科學數據，加上保守估計因氣候變化所需付出的成本，史登報告估算，如果這樣的現象無法改善，氣候變化所造成的損失將相當於全世界國民生產總值(GDP) 的 5%！
史登報告接著提出最新的科學證據( 例如溫室氣體可能會隨南北極永凍層的融化而自然釋放)、對人類生活和環境產生的經濟影響、以及對貧窮人口所造成影響必須適當加權的模型和觀點。若將上述因素都納入計算，史登報告估計，氣候變化可能帶來的損失將上升到GDP的20%或者更多。
相反的，如果採取行動減少溫室氣體排放來避免氣候變化的最大衝擊，它所需的成本，可以被控制在每年約全世界國民生產總值的1%。人們雖然要用比較高的價錢來購買低碳製程的產品，但是我們的經濟卻可以持續穩健增長。
如果我們不採取行動減少溫室氣體排放，我們所排放的每一噸二氧化碳至少造成85美元的損失，然而這些額外的成本，在投資者和消費者做決定要如何花錢時，並沒有被計算在內。近年來實行的二氧化碳減排交易的新方案顯示，我們很有機會能將二氧化碳排放減量的成本，降低到每噸25美元以下。換句話說，溫室氣體減量能讓我們獲利。
朝向低秏碳型經濟轉型也將帶來巨大的商機。如果全世界都按照要求的規模行動，估計到2050年低碳技術的市場產值將達到、甚至超過5,000億美元。鑑於台灣在高科技發展的傑出經驗，這個領域將會是台灣的大好機會。
因應全球氣候變化是一種有助成長的策略，忽略它終會妨礙經濟成長。
史登報告的後半部說明，朝向低秏碳型經濟發展所面臨的政策挑戰。氣候變化是迄今為止最嚴重的市場失靈現象。史登也建議，制定有效的應對政策，需要考慮三個要素：
第一、碳交易的定價。這可以透過稅收、排放交易、或法規來進行，讓人們負擔起其行為造成的所有社會成本。我們需要建立一個跨國性和跨產業的碳定價原則。近來已經向立法院提出的溫室氣體減量法，正是朝向這方向積極努力的第一步。
第二、以科技政策推動低秏碳與高能源使用效率產品的開發和廣泛應用。
第三、消除提高能源效率的阻礙，對人們進行宣導、教育和說服，面對氣候變化他們應該做些什麼。能源效率的提升對企業來說也是雙贏。
採取有效行動需要全球性的政策回應，這需要建立在各國對氣候問題政策長遠目標的共識，以及穩固的合作框架上。
◎ 附註：
- 工業革命前，大氣中溫室氣體濃度相當於280ppm（換算成二氧化碳），而目前的濃度相當於430ppm。
- 該報告中驗視了來自於許多不同經濟模型的證據，這些模型研究氣候變化的沖擊，以及減少沖擊所需投入的成本和帶來的益處。其中一個模型PAGE2002用來闡述將新的科學證據和更廣泛的負面影響全部考慮進去之後產生的結果。選用這個模型是因為該模型特別允許對於風險和不確定因素進行比較極端的統計。
- 史登爵士的研究報告可由www.sternreview.org.uk進行下載。該報告的背景資料，包括參考目錄以及“要求提供證據”的回覆結果，也可以在該網站找到。
- 尼古拉斯．史登爵士是政府經濟服務部門的負責人，英國政府在氣候變化經濟學及其發展研究方面的顧問，世界銀行的前首席經濟學家。
- 本文發表於11月3日台灣環保署與英國貿易文化辦事處代表處聯合記者會上。
I am very pleased to be able to hold this joint press conference with the Environmental Protection Administration (EPA), highlighting the importance that we both attach to the issues raised in the Stern Review.
The Stern Review of the Economics of Climate Change was published earlier this week (Monday 30 October) in London. It is the most comprehensive review ever of the economics of climate change. The Review was commissioned by the UK Chancellor of the Exchequer (Minister of Economic Affairs/Finance) in July last year. It has been carried out by Sir Nicholas Stern, Head of the Government Economic Service and former World Bank Chief Economist.
The review highlights that the scientific evidence of climate change is now overwhelming and it contains some stark figures for the potential impact. However, the conclusions are essentially optimistic: there is still time to avoid the worst effects of climate change, if we act now.
The first half of the Review focuses on the impacts and risks arising from uncontrolled climate change, and on the costs and opportunities associated with action to tackle it. Economic models over timescales of centuries do not offer precise forecasts – but they are an important way to illustrate the scale of effects we might see.
The Review finds that all areas of the world will be affected by climate change. Taiwan is no exception, with potential flooding and changes in typhoon patterns of particular concern. If no action is taken, climate change risks raising average temperatures by over 5°C from pre-industrial levels. Such changes would transform the physical geography of our planet, as well as how and where we live our lives.
Adding up the costs of a narrow range of the effects, based on the assessment of the science carried out by the Intergovernmental Panel on Climate Change in 2001, the Review calculates that the costs of the consequences of this would be equivalent to at least 5% of global GDP each year.
The Review goes on to consider more recent scientific evidence (for example, of the risks that greenhouse gas will be released naturally as the permafrost melts), the economic effects on human life and the environment, and approaches to modelling that ensure the impacts that affect poor people are weighted appropriatedly. Taking these together, the Review estimates that the dangers could be equivalent to 20% of GDP or more.
In contrast, the costs of action to reduce greenhouse gas emissions to avoid the worst impacts of climate change can be limited to around 1% of global GDP each year. People would pay a little more for carbon-intensive goods, but our economies could continue to grow strongly.
If we take no action to control emission, each tonne of CO2 that we emit now is causing damage worth at least $85 – but these costs are not included when investors and consumers make decisions about how to spend their money. Emerging schemes that allow people to trade reductions in CO2 have demonstrated that there are many opportunities to cut emissions for less than $25 a tonne. In other words, reducing emissions will make us better off.
The shift to a low-carbon economy will also bring huge opportunities. Markets for low-carbon technologies will be worth at least $500bn, and perhaps much more, by 2050 if the world acts on the scale required. Given Taiwan’s history of excellence in high-tech industries, this represents a real opportunity for Taiwan.
Tackling climate change is the pro-growth strategy; ignoring it will ultimately undermine economic growth.
The second half of the Review examines the policy challenges of moving to a low-carbon global economy. Climate change is the greatest market failure the world has seen. Three elements of policy are required for an effective response.
The first is carbon pricing, through taxation, emissions trading or regulation, so that people are faced with the full social costs of their actions. This aim should be to build a common global carbon price across economies and sectors. The recently submitted Greenhouse Gas Reduction Bill is a welcome first step in this area.
The second is technology policy, to drive the development and deployment at scale of a range of low-carbon and high-efficiency products. And the third is action to remove barriers to energy efficiency, and to inform, educate and persuade individuals about what they can do to respond to climate change. Such efficiency is clearly a win-win for businesses.
Effective action also requires a global policy response, guided by a common international understanding of the long-term goals for climate policy and strong frameworks for co-operation.
