“……both the research literature and government reports that summarize and assess the state of climate science say clearly that heat waves in the US are now no more common than they were in 1900, and that the warming temperatures in the US have not risen in the past fifty years…”*
根據研究，美國現在的氣溫在過去50年間並未明顯上升。
“Unsettled?”這本書的作者Steven E. Koonin，在分析各種關於全球暖化的研究報告之後發現，媒體及環保人士，傾向於誇大研究資料中較悲觀、糟糕狀況的預測結果，但是並没有說明預測模型背後的假設條件，充滿了巨大的不確定性。
所以，他認為全球暖化的議題，在研究的層面，是否已有定論有待商榷(unsettled)，呼籲大家要直接回去看數字，以更客觀、冷靜、務實的態度，來看待全球暖化的議題。
對全球暖化，他總結了三項保守的做法：
“Keeping human influences on climate below levels deemed prudent by the UN and many governments would require that global carbon dioxide emissions, which have been rising for decades, vanish sometime in the later part of this century.
Emissions reductions would have to take place in the face of growing energy demand driven by demographics and development, the dominance of fossil fuel, and the current drawbacks of low-emission technology.
There’s barriers, combined with the uncertainty and vague nature of future climate impacts, mean that the most likely societal response will be adapt to a changing climate, and that adaptation will very likely be effective.”*
節能減碳，減少對石化燃料的依賴，加重綠色能源的開發，在21世紀前達到碳的零排放，並且隨著氣候的改變即時有效地修正做法。
除了節能減碳，還可考慮以下的措施：
1. 增加地球的反射(屋頂弄成白色)
3. 主動從空氣中抽取二氧化碳(每噸高達100美元，成本很高)
4. 種樹(樹木成林需要幾十年的時間)
“……The impact of human influences on the climate is too uncertain(and very likely too small) compared to the daunting amount of change required to actually achieve the goal of eliminating net global emission by, say, 2075. And for me, the many certain downsides of mitigation outweigh the uncertain benefits: world’s poor need growing amounts of reliable and affordable energy; and wide-spread renewables or fission are currently too expensive, unreliable, or both. I would like to wait until the science becomes more settled—that is, until the climate’s response to human influences is better determined, or, failing that, until a values consensus emerges or zero-emissions technologies become more feasible—before embarking on a program to tax or regulate greenhouse gas emission out of existence or to capture and store massive amounts of carbon dioxide from the atmosphere.”*
這其中最重要的概念，是隨時氣候的改變，我們要隨時調整做法，而不是要求一步到位。
嚴格的節能減碳措施，一方面效果難料，另外一方面對於開發中國家改善較不富裕的人的生活品質，會是一大打擊。
對於全球暖化的議題尚未得到共識之前，Seven E. Koonin建議大家要務實以對。
P.S. 中央社對2023年聯合國最新資料的報導，聯合國呼籲開發國家在2040前達成零碳排放：
「倘若按目前的速度暖化，全球均溫將在本世紀末上升攝氏3.2度，即便實現當前目標，仍有可能升高至少攝氏2.2度。
全球均溫已較1850-1900年水準高出攝氏1.1度，引發了更多極端天氣事件。」
*：Seven E. Koonin，Unsettled? What climate science tells us, what it doesn’t, and why it matters，2021，BenBella Books, Inc.
2023/7/21 Unsettled? What climate science tells us, what it doesn’t, and why it matters? Damakey
