隨著經濟的發展，人類對環境的污染也日益嚴峻。在交額爛頭之時，我們將目光交給那些兢兢業業的專家們。政府間氣候變化專門委員會成立于1988年，專家組成員曾于2007年被聯合授予諾貝爾和平獎。它最初是由聯合國環境保護項目和世界氣象組織聯合發起組織的，目的是為了定期整合已有的關于氣候變化原因與后果的研究結果和學界對這些研究結果的反應。專家組通常會提供大篇的技術報告及相應的簡短摘要，用以描述社會發展對于氣候變化產生的可能影響。然而，各國政府的“言行不一”讓專家組的一些領導人不得不站出來，明確表示他們對于政策制定的意見，科學并不能告訴社會該做些什么，因為現實并不像理論上的那樣簡單。

Can Climate Panel（專門小組） Have Climate Impact?

I have an article in Tuesday’s Science Times（《科學時報》） assessing next steps for the Intergovernmental Panel on Climate Change（政府氣候變化專門委員會）. The panel, which shared the Nobel Peace Prize （諾貝爾和平獎）in 2007, was created in 1988 under the United Nations Environment Program and World Meteorological Organization （聯合國環境計劃署和世界氣象局）to aid governments by periodically reviewing the accumulated research on the causes and consequences of climate change and possible responses. But it was proscribed from recommending particular courses of action.

The task of being policy relevant but policy neutral has become ever tougher, it seems. The massive（大量的） reports and shorter summaries（摘要） are certainly relevant to global and national energy policies, describing the possible climatic outcomes of a wide range of societal paths, from business as usual to aggressive emissions curbs. But so far, as the article notes, there’s scant（缺乏） evidence that world leaders, while lauding（贊美） the climate panel and publicly accepting its periodic conclusions, are taking them to heart.

That disconnect（言行不一致） has prompted some leaders of the climate panel, including Rajendra K. Pachauri, its chairman since 2002, to speak out （毫無保留地說出）strongly in favor of certain policy choices, from deep cuts in emissions by developed countries （從降低發達國家的有害物質排放量）to steps taken on energy and climate by President Obama and Congress in the United States.

In an interview, Dr. Pachauri readily acknowledged that he presses for particular actions（明確地承認曾表達過類似的意見）, but said he does so as an individual（但是是個人觀點）. He said this does not present a conflict. “When I quote from the I.P.C.C（專家組的調查報告）. I make sure that whatever I say is totally accurate,” he said. “But that doesn’t prevent me from expressing my own views. I do get criticism, but if you stand still you won’t get anywhere.”

Gerbrand Komen, who was the longtime head of the Dutch government delegation at climate-panel plenary meetings（荷蘭政府代表團的負責人參加專家組的全體大會） and is a former director of climate research at the Royal Netherlands Meteorological Institute（荷蘭皇家氣象學院）, said that the climate panel is, in essence, presenting mixed messages and assuming mixed roles.

“I like to distinguish people trying to understand the world and people trying to change the world,” Dr. Komen said in an email. “I.P.C.C. (’policy relevant, but not policy prescriptive’（政策相關但不引導政策制定）) is in between. In all three groups [the climate panel's working groups on the science（科學問題組）, impacts and adaptive response（氣候變化影響和適應性應對組） and mitigation of human-caused warming（人為原因導致氣候變暖應對組）] there are people that ignore uncertainty bands, and emphasize extremes, for various reasons: be it curiosity or the wish to influence policy. Modelers sometimes tend to forget that their models are only models.”

Discussions of climate science and policy have seen endless fights over the appropriate role of scientists. Should they limit themselves to laying out the evidence, uncertainties and all, and let society respond however it may? Or should they be as free as any citizen to dive into the policy debate, as James Hansen of NASA and Dr. Pachauri (who is an engineer and economist) have done?

And if you endorse such actions by Dr. Hansen（如果你贊同漢森博士的說法）, can you criticize them when the scientist/advocate stakes an entirely different ideological or economic position? In 2007, on the C-Span program “Close Up at the Newseum（聚焦新聞博物館）,” I asked Patrick J. Michaels, a climatologist working with the Cato Institute who unabashedly labels his work “ advocacy science,” just what that phrase means. He offered a defense reaching back to Thomas Jefferson’s encouragement of scientists to be citizens.

In the end, many people in this arena insist, the science frames the discussion, providing the best picture of consequences and opportunities while laying out ranges of risk and uncertainty. In its 21 years, the Intergovernmental Panel on Climate Change（政府氣候變化專門委員會） has played a unique role in facilitating just that framing, many panel members and experts on science and policy say.

But in the end, I hear again and again, science doesn’t have a role in telling society what to do. If only things were that simple. Kenneth Caldeira, a climate specialist whom I’ve interviewed about ocean acidification（海洋酸化）, geo-engineering（地質工程學）, climate tipping points（氣候劇變點） and other questions, says there is substantial peril in “describing policy prescriptions as if they’re a scientific conclusion.”

He bases his thinking on some fundamentals of philosophy, as laid out by David Hume long ago. “You can’t get an ought from an is,（你不能僅從事實的描述中推出我們現實中應該做什么）” Dr. Caldeira told me.

Keke View：政府間氣候變化專業委員會（IPCC）

IPCC是一個政府間機構，它向UNEP和WMO所有成員國開放。在大約每年一次的委員會全會上，就它的結構、原則、程序和工作計劃作出決定，并選舉主席和主席團。全會使用六種聯合國官方語言。

IPCC設有三個工作組：第一工作組評估氣候系統和氣候變化的科學問題；第二工作組的工作針對氣候變化導致社會經濟和自然系統的脆弱性、氣候變化的正負兩方面后果及其適應方案；第三工作組評估限制溫室氣體排放和減緩氣候變化的方案。另外還設立一個國家溫室氣體清單專題組。每個工作組（專題組）設兩名聯合主席，分別來自發展中國家和發達國家，其下設一個技術支持組。