Sustainability Now

不要对全球变暖充满恐惧

Sep 13, 2013 Bjørn Lomborg

马尔默——9月26日，联合国政府间气候变化专业委员会（IPCC）将提交23年中第五份、也是最新一份评估报告的摘要。虽然IPCC并不完美——它众所周知曾经预测喜马拉雅冰川将于2035年消失，其实冰川消失的年份更有可能是2350年——但一般情况下IPCC的众多专家仍为我们提供了有关全球气候变暖这一棘手问题的最可靠的信息。

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大规模泄露已经让报告内容为外界所知。并且因为已经有过四次先例，人们已经对报告的政治作用非常熟悉。但因为20年来解决气候变化问题的努力还没有取得实质性的成果，这次也许应该探索新的策略。

新报告的基本结论是全球变暖切实存在，而且大多可以归咎于人类活动。报告花费大量篇幅表述这样一个观点：IPCC现在对1950年来全球升温的半数以上由人类引起这一结论更有把握（把握性已经从2007年的90%达到95%）。但这仅仅证实了我们早已知道的结论——燃烧化石燃料释放二氧化碳，进而导致地球温度升高。正像得克萨斯州农工大学气候学家安德鲁·德斯勒在推特上所说的那样：“即将发布的IPCC报告主旨：‘和我们2007、2001、1995、1990年报告并没有多少差别…”

具体地讲，6月份的报告草案显示出与早期报告“类似”的温度上升，到本世纪末的升温幅度约为1.0-3.7摄氏度。IPCC目前的海平面上升预测采用了3-20厘米的冰川响应模型，由此得出世纪末预计升幅提高40-62厘米——明显低于很多环保主义者、甚至某些媒体大肆宣扬的海平面上升1-2米的惊人而夸张的数字。

同样，IPCC通过降低所谓气候敏感性预测下限数据导致气温升幅降低。目前有关人类活动导致1950年来飓风和干旱事件的确定性同样在降低。2007年报告上述确定性达到50%以上；而现在则下降到不足21%。

但是这些适度合理的结果无疑将在危言耸听面前碰壁。很多人将仿效一个名叫乔·罗姆的博主，乔公然宣布“这份极端保守而且从一开始就已经过时的报告忽视了最新的科学证据，”乔继续宣称温度上升5º C和海平面上升6英尺（1.8米）。罗姆和其他人在2007年IPCC报告发布后曾经做出过类似的评论，声称更惊人的最新研究成果并没有被包括进去。

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全球温度近10-20年来几乎并未升高是IPCC更大的问题。需要说明的是，这样的放缓并不意味着没有全球变暖——这一趋势是无可否认的；但变暖程度的确是个问题。

值得称道的是，IPCC承认“该模型在过去10–15年的地表变暖趋势中并不总能推算出实际观测到的降幅。” 这一点非常重要，因为如果模型近几十年的数据都出现偏差，它对整个世纪预测的准确度就值得怀疑。

和1980年来的实际升温幅度相比，32个顶级气候模型（也就是所谓的CMIP5）的平均超估率达到71-159%（见图）。自然气候变化机构一项新的研究表明目前的主流气候模型过去15年超估的温度升幅达到300%多。

今年的几项研究显示大西洋或太平洋的自然循环可能导致温度升幅放缓，周期性因素导致二十世纪八九十年代升温幅度大，而今天的全球变暖步伐已经放缓或者停止。全球变暖或许切实存在，但过去可能有所夸大，而今天又可能估计不足。

研究结果凸显了IPCC一贯坚持的事实：只有超过半数的升温是由人类导致的，但在公开讨论中人类的作用常常被夸大为全部。IPCC强调气候变化的确是问题；但报告中并没有媒体大肆渲染的典型的末日场景、没有危言耸听、也没有自然科学家要求削减X%碳排放、或者给予太阳能电池板大笔补贴。

叫嚣采取行动的游说势力和拼命挖掘坏消息的媒体几乎肯定将淹没IPCC的理性研究。事实上，尽管IPCC根据其自身原则本该定义为政策中立机构，但其负责人拉金德拉·帕乔里却通过强调“人类已将世界气候系统推到了崩溃的边缘”和我们或许需要借助某种“碳排放成本”完成“从化石燃料的过渡”来公开煽动民众的狂热情绪。

因此报告发布的结果可能还会和从前一样：四处宣扬恐怖的场景，之后是政治家许诺巨额碳减排和代价巨大的政策，但其实对气候变化几乎没有影响。

也许我们应该尝试改变现有状况。我们应当接受全球变暖切实存在。但我们也应该承认现有政策代价巨大，却没有多少作用。漫长的87年中每一年欧盟都将为目前的气候政策支付2500亿美元。耗资近20万亿美元后，本世纪末的气温将下降难以觉察的0.05ºC。

现有的绿色能源技术仍然成本过大、产出过小，难以撼动传统能源地位。坚持采购这些不是方案的方案是本末倒置的做法。我们需要投资绿色能源研发以扩大规模降低成本。当太阳能和其他绿色能源可以经济地替代现有能源，我们就能够轻松解决全球变暖问题。

翻译：Xu Binbin

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Bjørn Lomborg

Writing for PS since 2005
176 Commentaries

Bjørn Lomborg, a visiting professor at the Copenhagen Business School, is Director of the Copenhagen Consensus Center. His books include The Skeptical Environmentalist, Cool It, How to Spend $75 Billion to Make the World a Better Place, The Nobel Laureates' Guide to the Smartest Targets for the World, and, most recently, Prioritizing Development. In 2004, he was named one of Time magazine's 100 most influential people for his research on the smartest ways to help the world.

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0 Comments on this paragraph, 23 Comments on this article

Bertrand Monin Nov 17, 2013

oops sorry, one mistake in my previous calculations below.
$5.6 trillion did not take into account the hypothesis of $20 bn policy cost since 2050. Otherwise, the result is even lower at $4.7 trillion (28% of EU's current GDP)
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Bertrand Monin Nov 17, 2013

I think that this paragraph hypothesis are highly questionable:
(i) in one of your comments you do take into account a 3% discount factor to evaluate the future economic benefits of todays $250bn investments; why not also discounting the annual costs of the policy for the coming 87 years? A 3% discount factor with an hypothesis of $250 bn annualy has in fact a $8 trillion dollar policy cost (fared in todays dollar value) and not $20 trillion over 87 years;
(ii) I would assume, with great certainty, that the cost of the policy will not remain at $250 bn (in 2013 $) in the coming 87 years: government feed in tarifs and green certificate subsidies will become less and less expensive with renewable energy prices matching fossil fuel energy prices in the coming decades. It is even highly probable that no green certificates or feed in tarif subsidies at all will be necessary within the next 20 to 30 years.
I have reduced the cost of the policy by 1.5% every year in real terms until 2050 where I simply assume a $20bn cost flat in real terms as no major incentive policy should be necessary anymore given current trends. Assuming a 3% discount rate the cost of the policy for 87 years is not $20 trillion anymore, nor $8 trillion, but $5.6 trillion in todays dollar, that is 1/3 of EU's current GDP: not that bad for a policy planned for a century and designed to save the planet!

Your assumptions, not taking account discounting rate and the reduction of policy cost given current trend in susbsidies price seem very simplistic don't you think?
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Bertrand Monin Nov 16, 2013

Thanks for your clarifications Stephan Rahmstorf.

I sometimes have the uncomfortable impression that Project Syndicate's readers often have more intellectual probity than some of its columnists on various "fractious" issues. It is a pleasure to share the reading of an article with a community of readers who cares for accuracy and honesty, even if the columnist does not fully share this concern.
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Stefan Rahmstorf Nov 11, 2013

Stick to the facts: In a regional chapter on Asia in Working Group 2 (climate impacts) of the 4th IPCC report, written by authors from the region, it was erroneously stated that 80% of Himalayan glacier area would very likely be gone by 2035. This was of course not the proper IPCC projection of future glacier decline, which is found in the Working Group 1 report (which is the one about basic climate science, including the future projections of climate change). There we find a 45-page, perfectly valid chapter on glaciers, snow and ice (Chapter 4), with the authors including leading glacier experts (such as my good colleague Georg Kaser from Austria, who first discovered the Himalaya error in the WG2 report). There are also several pages on future glacier decline in Chapter 10 (“Global Climate Projections”), where the proper projections are used e.g. to estimate future sea level rise. So the problem here is not that the IPCC’s glacier experts made an incorrect prediction. The problem is that a WG2 chapter, instead of relying on the proper IPCC projections from their WG1 colleagues, cited an unreliable outside source in one place. Fixing this error involves deleting two sentences on page 493 of the WG2 report. This was an unfortunate citation error by the WG2 colleagues from Asia, but it was not based on an incorrect prediction by the IPCC climate scientists, as you well know.
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Stefan Rahmstorf Nov 11, 2013

Stick to the facts: the IPCC does in fact give as its best estimate all of the warming since 1950 is caused by humans. The natural contributions are estimated to be about zero and constrained to be within -0.1 and +0.1 °C for both internal and externally forced natural variability. That is why the IPCC writes in the Summary for Policy Makers (available at www.ipcc.ch): "It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century."
I wonder why you keep downplaying the serious risk that global warming poses to human civilisation, even to the extent of distorting to your readers what the IPCC (i.e. the scientific community at large) finds.
- Bjørn Lomborg Aug 6, 2014
 
 Dear Stefan.
 Your claim is simply wrong. The IPCC does not claim that *all* warming is due to humans. They say it is above 50%. This is *exactly* why they say "human influence has been the dominant cause of the observed warming since the mid-20th century." (Dominant meaning more than half the cause.) If they believed that humans were the full reason, they would have written 'human influence is the only cause of the observed warming since the mid-20th century.' Pls don't misrepresent the science.
 If you want, you can read the IPCC summary, where they actually explain what they mean with 'dominant' in the very next sentence: "It is extremely likely that more than half of the observed increase in global average surface temperature from 1951 to 2010 was caused by the anthropogenic increase in greenhouse gas concentrations and other anthropogenic forcings together."
 "More than half" -- not all of it. Or as I wrote: "humans have caused more than half of the global rise in temperature since 1950."
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Stefan Rahmstorf Nov 11, 2013

Stick to the facts: the IPCC writes about sea level in its Summary for Policy Makers (available at www.ipcc.ch):
"For RCP8.5, the rise by the year 2100 is 0.52 to 0.98 m".
(RCP8.5 is a scenario with unmitigated rise in greenhouse gas emissions.)
For the lowest emissions scenario RCP2.6 (which involves drastic emissions reductions starting in a few years and leading to zero global emissions by 2070, after that active removal of CO2 from the atmosphere) the best estimate sea-level rise by the year 2100 given by IPCC is 44 cm. 
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Jeffrey Scofield Sep 23, 2013

There tends to be a focus on atmospheric global warming and little discussion of oceanic warming or ocean acidification. Since carbon in the ocean is captured for a longer timeframe than the atmosphere, thus failure to reduce CO2 levels now will elevate acids in the ocean for a very long time, I'd like to see more attention from Mr. Lomborg addressing this concern. Coral reef ecosystems and fisheries industries are almost always left out of the discussion of the importance of immediate action. Research in future technologies doesn't address the amount of waste and inneficient we are partaking in at the present.
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Fernando Herrero Sin Sep 22, 2013

Why don't you weigh the cost of inaction against the cost of over-caution?
Yes, much more investment in research and development (and much more in deployment -which is what actually boosts scale) of green technologies is needed. Yet, much more prescient is an unmistakable assertiveness to decarbonize the world energy system. Articles such as this one are not productive in this regard. On the contrary, articles that question the legitimacy of climate scientists' claims fuel climate skeptics' agendas and buy time to fossil-fuel-intensive industries. We need to understand that given that the science is not yet perfectly capable to describe the human-climate system, the embedded uncertainty of the risks associated with climate change can only add urgency to decarbonization.
- Fernando Herrero Sin Dec 4, 2015
  
  You can read how the IEA calls you out on your lies and misinformation
  http://cleantechnica.com/2015/12/04/iea-lomborgs-claims-about-wind-solar-energy-are-rubbish/
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- Bjørn Lomborg Sep 23, 2013
  
  Dear Fernando Sin. Thanks for your comment. The cost of action vs cost of inaction comparison is a red herring, because it does not compare what we can actually achieve (the outcome of the action is almost the same as the outcome of inaction even on a 50-75yr scale, because of long lag times in the climate system).
  Take a look at my argument here: http://www.project-syndicate.org/commentary/misusing-the-inaction-argument
  A new reply to this comment has been posted.
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Andrew Urban Sep 20, 2013

“….the rigid orthodoxy of modern environmentalism” is the phrase that jumped out when I read Robert Stone’s Director’s Statement prior to the Australian release of his Sundance-selected doco, Pandora’s Promise. The most important aspect of Stone’s film is that it is a record of high profile, articulate and opinion-driving activists having unlocked, opened and changed their minds, escaping that rigid orthodoxy. Would this happen more often, more broadly, so as to enable a rational debate on the best ways to replace fossil fuels with renewable, clean and endless supplies. The divisive 'believers' v 'deniers' climate of debate is destructive and damages democracy.
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Brian Thomson Sep 19, 2013

There are a few things we need to consider that the article does not address. First, the cost of renewable energy, especially solar and wind, have fallen precipitously over the last decades. This was only partially the result of R&D, a much larger part of the fall in prices was from what engineers call "learning by doing." In other words, as we build more solar panels, we get better at building them.

This combined with economies of scale (the millionth solar panel is cheaper to build than the first solar panel) is making solar and wind more affordable than ever. Taken together, learning by doing and economies of scale mean that a research only approach would not drive down prices as quickly as policies that actually install more renewable energy.

The second thing that we should consider is called the "locational marginal price of electricity." In a nut shell, electricity transmission lines suffer from congestion, just like roads do. But just like roads, congestion is only present during peak use; Look at any highway at 3AM and it is empty. By distributing energy generation (think rooftop solar) close to where it will be consumed, we are reducing the need to invest in transmission wires that are only used for a few hours of peak energy use per year. this comes at considerable cost savings.

This brings me to a third point. Since solar is a very good peak generator, comparing its costs with the average cost of electricity is not fair. Solar should be compared with other peak generators, which are always more expensive than the average. Fossil fuel peaker plants are not necessarily cheaper than using solar to generate peak energy.

Think I am a hippie? Well, don't take my word for it, the electric industry is catching on. Xcel Energy, one of the largest utilities in the united states recently told the Colorado Public Utility Commission, "Based on generation needs, the most reliable and most cost-effective resources happen to be solar and wind. We are not [advocating more] solar because we have to, but because it is cost-effective and economical." This is just the latest in industry recognition that renewables are cost competitive, reliable, protect human health, and ensure a stable climate.

This means that
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Stamatis Kavvadias Sep 18, 2013

When the author reaches his conclusions, the objectivity of the whole article comes to question!

What is so excessive about $250 billion annually for the EU? It amounts to about 1.1% of its current aggregate GDP (~16.5 trillion euro -- not dollars), which will diminish as a percentage considering the growth in 87 years. What is so strange for $20 trillion in 87 years????? Estimating current global GDP conservatively at 70 trillion, and assuming no growth (which is impossible), 20 trillion amount to *less than* 3.3‰ of the cumulative world GDP for 87 years! And that would accomplish transition to clean and more sustainable energy, and the associated improvement in the quality of life of every living soul on the planet, for 87 years!!!

Clearly, there are no real arguments in the author's perspective.
- Stamatis Kavvadias Sep 23, 2013
  
  I understand now you said the article quantifies "the benefit of the reductions". Does it take into account all possible benefits? Namely, does it include reduction of natural disasters? Anyway, thanks for your article.
  A new reply to this comment has been posted.
- Stamatis Kavvadias Sep 23, 2013
  
  Thank you for your answer.
  I suppose, the estimates in the article (I could not find a free version and it does not use easily understandable metrics) would not include benefits because of reduction of natural disasters, (there is only 21% certainty they are man made in the upcoming IPCC report), would they? Anyway, $250 billion for EU may be a lot (it almost completely absorbs an average GDP growth of 1% over 87 years), but the question should also be whether it is enough.
  
  Instead of addressing only one side of these questions, I would ask a different question: how much of the effects to which climate change possibly contributes can be avoided by CO2 reductions? This question does not mask costs and benefits and is much more important anyway!
  A new reply to this comment has been posted.
- Bjørn Lomborg Sep 19, 2013
  
  Dear Stamatis Kavvadias.
  
  Thanks for your comments. You are of course welcome to think that $250bn for virtually no impact is a bargin (incidentally, Connie Hedegaard agrees with you, http://bit.ly/1gpjL9J), but I doubt most Europeans would appreciate their money spent in this way.
  
  Also, if you look at http://dx.doi.org/10.1016/j.enpol.2012.06.018, it estimates the benefit of the reductions (the avoided climate damage) at 3% pure discount rate is €7.1bn -- this means that for each euro spent, we have avoided €0.03 in damages.
  
  This, I would argue, is the definition of a bad investment.
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- Stamatis Kavvadias Sep 18, 2013
  
  That's still 25% less than Greek GDP at the beginning of the crisis...
  A new reply to this comment has been posted.
- Stamatis Kavvadias Sep 18, 2013
  
  I made a mistake for EU GDP: it is a bit more than $16.5 trillion (not euros). So, my calculation is slightly wrong for EU. $250 trillion amount to ~1.5% of aggregate GDP, to be accurate.
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- Stamatis Kavvadias Sep 18, 2013
  
  To put $250 billion in perspective, it is about the current size of Greek GDP, after 3 and a half years of austerity.
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Jan Kjetil Andersen Sep 17, 2013

Thank you for an overall good article, but where do you get the cost of EU’s climate policy to come to $250 billion annually.

I think the cost can be estimated in many ways, but one fair way to do it is to compare it with buying carbon credits. After all, an alternative to domestic reductions is to buy carbon credits.

The carbon credits for the obligation from the Kyoto agreement is far cheaper than 250 billion annually.
- Bjørn Lomborg Sep 18, 2013
  
  Dear Jan Kjetil Andersen.
  
  Thanks for your comment. The cost of $250bn comes from this paper: http://dx.doi.org/10.1016/j.enpol.2012.06.018; which uses the average of 5 different climate-economic models to estimates the gdp loss to the EU economy at about €209bn (or about $250bn).
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m r Sep 15, 2013

It is often said that those who have no "solutions" for the problem they countenance, they insist that a "Ministry" (here: Research and Development) be established to solve the deemed problems. So it is not right that the author demeans "ALL" the efforts taking place round the world, howsoever expensive OR little, just because they seem so to his own intellectual agenda.
Something is always better than nothing, even if wrong.
The author could well do to enter the fray and say which "levers", if there be any he would like twisted and turned to achieve his utopia and expose himself thereby to be damned. We may then get a better input from him.
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