- Stern Review
The Stern Review on the Economics of Climate Change is a 700-page report released on
October 30, 2006by economist Lord Stern of Brentford for the British government, which discusses the effect of climate changeand global warmingon the world economy. Although not the first economic report on global warming, it is significant as the largest and most widely known and discussed report of its kind. [cite web|url=http://www.thefirstpost.co.uk/index.php?menuID=2&subID=1055|title=" Time to get Stern on climate change"|author=Francis Cairncross|date= 30 October 2006|publisher="The First Post"]
Its main conclusions are that one percent of global
gross domestic product(GDP) "per annum" is required to be invested in order to avoid the worst effects of climate change, and that failure to do so could risk global GDP being up to twenty percent lower than it otherwise might be. Stern’s report [cite web | url=http://news.bbc.co.uk/1/shared/bsp/hi/pdfs/30_10_06_exec_sum.pdf |title="Stern Review executive summary" | author=Nicholas Stern | date= 30 October 2006| publisher= New Economics Foundation] suggests that climate change threatens to be the greatest and widest-ranging market failureever seen, and it provides prescriptions including environmental taxes to minimize the economic and social disruptions. He states, "our actions over the coming few decades could create risks of major disruption to economic and social activity, later in this century and in the next, on a scale similar to those associated with the great wars and the economic depression of the first half of the 20th century." [cite web
title="Report's stark warning on climate"
29 October 2006
BBC] [cite web|url=http://news.bbc.co.uk/2/hi/business/6096084.stm|title="Climate change fight 'can't wait'"|author=|date= 30 October 2006|publisher=BBC - video, executive summary and slide show.] In June 2008 Stern increased the estimate to 2% of GDP to account for faster than expected climate change. [http://www.guardian.co.uk/environment/2008/jun/26/climatechange.scienceofclimatechange "Cost of tackling global climate change has doubled, warns Stern"] , Juliette Jowit and Patrick Wintour in " The Guardian", June 26, 2008]
The "Stern Review" has been criticized by some economists, saying that Stern used an incorrect
discount ratein his calculations, and that stopping or significantly slowing climate change will require deep emission cuts everywhere. [Tol and Yohe (2006) "A Review of the Stern Review" "World Economics" 7(4): 233-50. See also other critiques in "World Economics" 7(4)] [Nordhaus, W. D., 2007. "A Review of the Stern Review on the Economics of Climate", "Journal of Economic Literature", Vol. 45 Issue 3, p686-702.] . Other economists have supported Stern's approach, [web cite|url=http://delong.typepad.com/sdj/2006/12/do_unto_others.html|title= Do unto others...|author= Brad DeLong] [web cite|url=http://johnquiggin.com/wp-content/uploads/2006/12/sternreviewed06121.pdf|title=Stern and the critics on discounting (unpublised)|author= John Quiggin] or argued that Stern's conclusions are reasonable, even if the method by which he reached them is incorrect. [web cite|url=http://isites.harvard.edu/fs/docs/icb.topic135505.files/Weitzman_Paper.pdf|title=The Stern Review of the Economics of Climate Change|author= Martin Weitzman] .
The draft report of the
Garnaut Climate Change Review, a similar study conducted in Australia in 2008 by Ross Garnautbroadly endorsed the approach undertaken by Stern, but concluded, in the light of new information, that Stern had underestimated the severity of the problem and the extent of the cuts in emissions that were required to avoid dangerous climate change.
19 July 2005the Chancellor of the Exchequer, Gordon Brownannounced that he had asked Sir Nicholas Sternto lead a major review of the economics of climate change, to understand more comprehensively the nature of the economic challenges and how they can be met, in the UK and globally. [web cite| url= http://www.hm-treasury.gov.uk/independent_reviews/stern_review_economics_climate_change/sternreview_backgroundtoreview.cfm#terms| title = Background to the Review] .
Previous debate in the UK
In 2004, along with six others, former UK
Chancellor of the Exchequer Nigel Lawsonwrote a letter to " The Times" criticising the consensus on climate change between the two major UK political parties [cite web | url=http://www.globalwarming.org/article.php?uid=795 | title=Distinguished signatories take on British political consensus | author=Iain Murray, Cooler Heads Coalition | accessdate=2007-11-20 | month=October | day=7 | year=2004] . In 2005, the House of LordsEconomics Affairs Select Committee, of which Nigel Lawson was a member, undertook an inquiry into the economics of climate change [cite web | url=http://www.publications.parliament.uk/pa/ld200506/ldselect/ldeconaf/12/12i.pdf | title=The Economics of Climate Change | author=House of Lords, Select Committee on Economic Affairs | accessdate=2007-03-14 | month=July | day=6 |year=2005] . The committee's report, "The Economics of Climate Change", recommended the UK Government make greater efforts to assess the costs and benefits of climate change mitigation and adaptation, and was also critical of the Kyoto Protocoland the IPCC.
Writing in "Prospect" magazine, Michael Grubb, Chief Economist of the
Carbon Trust, said that Kyoto's sequential targets helped to achieve many of the things the House of Lords report wanted [cite web | url=http://www.econ.cam.ac.uk/faculty/grubb/publications/GA09.pdf | title=Stick to the Target | author=Michael Grubb | accessdate=2008-01-24 | month=September | day=1 |year=2005] . David Pearce, who had earlier served the IPCC as a convening lead author, was the senior advisor to the House of Lords committee. Professor Grubb felt that there could be a link between the House of Lords report's criticism of the IPCC and David Pearce's earlier involvement with the IPCC. Professor Pearce had been the only IPCC convening lead author to have officially dissented on the government-negotiated "summary" of the chapter for which he was responsible. Pearce had also thrashed an earlier report by HM Treasury on the economics of climate change. [D.W. Pearce (2003), Oxford Review of Energy Policy, 19:1-32]
Lord Lawson responded to Grubb's article, describing it as an example of the 'intellectual bankruptcy of the ...climate change establishment'. Lawson also said that Kyoto's approach was 'wrong-headed' and called on the IPCC to be 'shut down' [cite web | url=http://www.prospect-magazine.co.uk/article_details.php?search_term=lawson&id=7117 | title=Against Kyoto | author=Nigel Lawson | accessdate=2007-11-20 | month=November | day=1 |year=2005] . The House of Lords report was much milder in tone, pointing at the mismatch between the costs and benefits of climate policy as estimated by independent academics and as assumed by politicians. The House of Lords report also lamented the lack of input of economists in climate policy making, and recommended that
HM Treasurytake a more active role.
The Stern Review was prepared by a team of economists at
HM Treasury; independent academics were involved as consultants only. The Stern Review emphasised the need for urgent action to be taken to mitigate climate change. In its assessment, the Review used one of the emission scenarios produced by the IPCC, some of which had been criticised in the House of Lords Economics report. A critique of the Stern Review was published in the "World Economics" journal, which described the Stern Review as being 'deeply flawed' [ [http://www.world-economics-journal.com/WEJArticle.asp?Vol=7&Iss=4&Id=261 Byatt, I. et al. (2006). "The Stern Review: A Dual Critique, Part II". "World Economics" 7(4)] ] . This critique included contributions from two members of the Economic Affairs Select Committee, Robert Skidelskyand Nigel Lawson. Some witnesses who presented evidence to the Select Committee have been critical of the Stern Review [For example, some of the authors of the critiques in "World Economics" 7(4) were witnesses before the Economic Affairs Select Committee or signatories of the earlier "Times" letter] .
Positive critical response
The Stern Review attracted positive attention from several sectors. Pia Hansen, a
European CommissionSpokeswoman, said doing nothing is not an option, "we must act now". Simon Retallack of the UK think tank IPPR said "This [Review] removes the last refuge of the 'do-nothing' approach on climate change, particularly in the US." Tom Delay of The Carbon Trustsaid "The Review offers a huge business opportunity." Richard Lambert, Director General of the Confederation of British Industry, said that a global system of carbon trading is "urgently needed". Charlie Kronick of Greenpeacesaid "Now the government must act and, among other things, invest in efficient decentralised power stations and tackle the growth of aviation."
Miles Templeman, Director-General of the
Institute of Directors, said: "Without countries, like the US, China or India, making decisive commitments, UK competitiveness will undoubtedly suffer if we act alone. This would be bad for business, bad for the economy and ultimately bad for our climate." [ [http://www.telegraph.co.uk/money/main.jhtml?xml=/money/2006/10/30/bcnste.xml http://www.telegraph.co.uk/money/main.jhtml?xml=/money/2006/10/30/bcnste.xml] ]
Asset managers F&C look to the business opportunities and say "this is an unprecedented opportunity to generate real value for our clients". [ [http://www.fandc.com/newsDetail_text.asp?newsID=576 http://www.fandc.com/newsDetail_text.asp?newsID=576] ]
Brendan Barber, General Secretary of the
Trades Union Congress, was optimistic about the opportunities for industry to meet demands created by investment in technology to combat climate change. [ [http://www.tuc.org.uk/economy/tuc-12578-f0.cfm http://www.tuc.org.uk/economy/tuc-12578-f0.cfm] ]
The Prince of Wales’ Corporate Leaders Group on Climate Change, formed by 14 of UK’s leading companies shared this hope. Chairman of Shell UK, James Smith, expressed the hope of the group that business and Government would discuss how Britain could obtain “first mover advantage" in what he described as "massive new global market". [ [http://www.telegraph.co.uk/money/main.jhtml?xml=/money/2006/10/30/bcnste.xml http://www.telegraph.co.uk/money/main.jhtml?xml=/money/2006/10/30/bcnste.xml] ]
November 1 2006, Australian Prime Minister, John Howard, responded by announcing that AU$60 million would be allotted to projects to help cut greenhouse gas emissions [ [http://www.news.com.au/story/0,23599,20682039-421,00.html http://www.news.com.au/story/0,23599,20682039-421,00.html] ] while reiterating that Australia would not ratify the Kyoto Protocol. Much of this funding is directed at the non-renewable coal industry.
British Prime Minister,
Tony Blair, stated that the Review demonstrated that scientific evidence of global warming was "overwhelming" and its consequences "disastrous" if the world failed to act. [ [http://news.bbc.co.uk/1/hi/business/6096084.stm BBC News: Climate change fight 'can't wait'] ]
The UK Treasury, which commissioned the report, simultaneously published a set of favourable comments from prominent economists and other leading figures:
* "If the world is waiting for a calm, reasonable, carefully argued approach to climate change, Nick Stern and his team have produced one. They outline a feasible adjustment policy at tolerable cost beginning now. Sooner is much better."
Robert M. Solow, Nobel Prize economist 1987cite web
title="PDF file of comments on the Stern Review by leading economists"
* "The Stern report shows us, with utmost clarity, while allowing fully for all the uncertainties, what global warming is going to mean; and what can and should be done to reduce it. It provides numbers for the economic impact, and for the necessary economic policies. It deserves the widest circulation. I wish it the greatest possible impact. Governments have a clear and immediate duty to accept the challenge it represents."
James Mirrlees, Nobel Prize economist 1996
* “The stark prospects of climate change and its mounting economic and human costs are clearly brought out in this searching investigation. What is particularly striking is the identification of ways and means of sharply minimizing these penalties through acting right now, rather than waiting for our lives to be overrun by rapidly advancing adversities. The world would be foolish to neglect this strong but strictly time-bound practical message.”
Amartya Sen, Nobel Prize economist 1998
* "The Stern Review of the Economics of Climate Change provides the most thorough and rigorous analysis to date of the costs and risks of climate change, and the costs and risks of reducing emissions. It makes clear that the question is not whether we can afford to act, but whether we can afford not to act. To be sure, there are uncertainties, but what it makes clear is that the downside uncertainties—aggravated by the complex dynamics of long delays, complex interactions, and strong non-linearities—make a compelling case for action. And it provides a comprehensive agenda—one which is economically and politically feasible—behind which the entire world can unite in addressing this most important threat to our future well being."
Joseph Stiglitz, Nobel Prize economist 2001
* "The Bank is committed to addressing the dangers of climate change and has made substantial progress in developing an Investment Framework for Clean Energy And Development. I very much welcome the Stern Review which provides a much needed critical economic analysis of the issues associated with climate change, and complements the recent IEA technology assessment and the World Bank's Clean Energy Investment Framework paper. The Bank is today working closely with its clients and partners to turn our analysis into practice, and will seek to substantially increase its own investment flows and those of the private sector. A crucial next step is to involve the private sector in the EIF. I am therefore pleased to support a partnership between the World Bank and the World Economic Forum and the World Business Council on Sustainable Development to stimulate private sector investment through the Energy Investment Framework. Chancellor Gordon Brown and I will co-host a conference early next year to launch the partnership."
Paul Wolfowitz, former President of the World Bank
* "The Stern Review of the Economics of Climate Change is a vital step forward in securing an effective global policy on climate change. Led by one of the world's top economists, the Stern Review shows convincingly that the benefits of early global action to mitigate climate change will be far greater than the costs. The report establishes realistic guidelines for action (based on long-term stabilization ceilings for greenhouse gases), core elements of an effective global policy (
carbon pricing, technology policy, and removing barriers to change), and a framework for international cooperation that must include all regions of the world, both developed and developing. The Stern Review will play an important role in helping the world to agree on a sensible post-Kyoto policy." Prof. Jeffrey D. Sachs, Director of the Earth Institute at Columbia University and Special Advisor to UN Secretary General Kofi Annan
* "The Economics of Climate Change sends a very important and timely message: that the benefits of strong, early action on climate change outweigh the costs. That conclusion is one that the International Energy Agency fully endorses - notably in its World Energy Outlook 2006 to be published next week. Congratulations to Sir Nick Stern and his team for producing a landmark review which I have no doubt will strengthen the political will to change of governments around the world."
Claude Mandil, Executive Director of the International Energy Agency
* "Climate change can impose enormous costs on mankind and particularly on the innocent poor people. The uncertainty that is used as an excuse not to act works both ways. If the impact is larger than expected it could be catastrophic. Sir Nick Sterns report is valuable as it shows the need to act now and that the costs of action are modest. One hopes it will spur to action those who are responsible for creating this threat."
Kirit Parikh, Member, Planning Commission, Government of India
* "The scientific evidence of global warming is overwhelming but some commentators and lobby groups have continued to oppose offsetting actions on economic and competitiveness grounds. This comprehensive and authoritative report demolishes their arguments, explaining clearly the complex economics of climate change. It makes plain that we can cut emissions radically at a cost to the economy far less than the economic and human welfare costs which climate change could impose"
Adair Turner, Former Director of UK Confederation of British Industry and Economic Advisor to Sustainable Development Commission
* "When the history of the world's response to climate change is written, the Stern Review will be recognized as a turning point. Sir Nicholas and his team have provided important intellectual leadership as humanity engages with its greatest challenge. While the details will be debated, the main thrust of the report is clear and compelling — the expected benefits of tackling climate change far outweigh the expected costs."
Cameron Hepburn, Oxford University
* "I support the Stern Review's conclusion that there is a strong economic case for taking early, effective action to reduce greenhouse gas emissions. This clearly has important implications for transport policy, which my own study is taking into account - sustainable economic growth cannot be achieved in any sector without tackling the effects of our actions on the environment".
Sir Rod Eddington, Adviser to the UK Government on the long term links between transport and economic growth, and former Chief Executive of British Airways
Some of these comments appeared at the same time as the Stern Review itself, even though the Stern Review was not reviewed by outsiders before publication.
Unfavorable critical response
The Stern review received numerous critical responses. Some critics, particularly economists, argued that Stern had overestimated the
present valueof the costs of climate change, and underestimated the costs of emission reduction. Others, particularly associated with business, argued that the economic cost of the proposals put forward by Stern would be severe, or that the scientific consensus view on global warming, on which Stern relied, was incorrect. By contrast, a number of critics, particularly natural scientists, criticised Stern from the opposite direction, arguing that he had underestimated the costs of damage to natural environments from climate change, and that more aggressive action to stabilise climate was needed.
Stern's modelling choices overstate damages
William Nordhaus, an economistat Yale Universitywho has done several studies on the economics of global warming, criticised the Review for its discount rateassumption [cite web
title="The Stern Review on the Economics of Climate Change"
author= William Nordhaus
Yale University website
May 3, 2007] :
Yale economist Robert Mendelsohn made similar criticisms in a BBC radio programme "The Investigation". A number of other economists and scientists on the programme argued that the review's assumptions were far more pessimistic than those of most experts in the field, and that while claiming to be a review of current academic thinking the Stern review's conclusions were in fact at odds with the mainstream view. [cite web
title="The Investigation" (audio)
author=BBC Radio 4
January 25, 2007]
Partha Dasguptacalls Stern's combination of pure rate of time preference and rate of risk aversion "patently absurd" as this would imply a savings rate of 97.5% while the observed rate is around 15%. [P. Dasgupta (2007), National Institute Economic Review, 199:4-7] Berkeley economist Hal Varianshares Dasgupta's critique. [H.R. Varian (2006), International Herald Tribune, December 15] Richard Tol, an environmental economist at the Economic and Social Research Instituteand lead author (amongst a total of over 450 lead authors) for the Intergovernmental Panel on Climate Change(IPCC), said that "If a student of mine were to hand in this report as a Masters thesis, perhaps if I were in a good mood I would give him a 'D' for diligence; but more likely I would give him an 'F' for fail. There is a whole range of very basic economics mistakes that somebody who claims to be a Professor of Economics simply should not make. (...) Stern consistently picks the most pessimistic for every choice that one can make. He overestimates through cherry-picking, he double counts particularly the risks and he underestimates what development and adaptation will do to impacts." [ [http://news.bbc.co.uk/2/hi/science/nature/6295021.stm BBC NEWS | Science/Nature | Running the rule over Stern's numbers ] ] Tol also showed that the Stern Review's estimate of the social cost of carbonis an outlier in the literature. [See also web cite|url=http://www.economics-ejournal.org/economics/journalarticles/2008-25/view|title=The Social Cost of Carbon: Trends, Outliers and Catastrophes|author= Richard Tol|accessdate=2008-08-12] Tol further referred to the Stern Review as "populist science". [ [http://archives.tcm.ie/businesspost/2008/01/27/story29910.asp Sunday Business Post, Jan 27, 2008] ]
Martin Weitzmanwrites [M.L. Weitzman (2007), Journal of Economic Literature, 45 (3): 703:724] that "the Stern Review consistently leans towards ... assumptions and formulations that emphasize optimistically-low expected costs of mitigation and pessimistically-high expected damages from greenhouse warming", that the documentation in the report is "elusive, frustrating, and ultimately unsatisfactory" and that "the key assumption that drives its strong conclusions is the mundane fact that a very low interest rate is postulated". Weitzman writes that "concerning the rate of pure time preference, Stern follows a decidedly-minority paternalistic view", and that "in a similar spirit of choosing extreme taste parameters, Stern selects as its base-case coefficient of relative risk aversion ... that is the lowest lower bound of just about any economist’'s best-guess range." Weitzman continues to argue that the Stern Review underestimated the risk of climate change and that, therefore, the Stern Review is "right for the wrong reasons", a conclusion shared by Yohe and Tol. [G.W. Yohe and R.S.J. Tol (2007), Environment, 49 (2):36-42] Australian economists Paul Jensen and Elizabeth Webster also criticize the paternalism in the Stern Review, and link this to Britain's imperial past. [P.H. Jensen and E. Webster (2007), Australian Economic Review 40(2):421-431]
In an [http://www.fnu.zmaw.de/fileadmin/fnu-files/publication/tol/Ruddock.pdf official letter] ,
Joan Ruddockdismissed the criticisms of Dasgupta, Mendelsohn, Nordhaus, Tol, Weitzman and Yohe as these economists suffer from "a fundamental misunderstanding of the role of formal, highly aggregated economic modelling in evaluating a policy issue".
Bjørn Lomborgcriticised the Stern Review in " OpinionJournal" [cite web
title="Stern Review. The dodgy numbers behind the latest warming scare"
author= Bjørn Lomborg
The Wall Street Journal
November 2, 2006] :
tern underestimates costs of mitigation
Professor Emeritus of Economics at
Pepperdine University George Reismansaid that "Any serious consideration of the proposals made in the "Stern Review" for radically reducing carbon technology and the accompanying calls for immediacy in enacting them makes clear in a further way how utterly impractical the environmentalist program for controlling global warming actually is. The fundamental impracticality of the program, of course, lies in its utterly destructive character." [cite web
title="Britain’s Stern Review on Global Warming: It Could Be Environmentalism’s Swan Song"
November 1, 2006] Reason magazine's science correspondent Ronald Baileyalso emphasized on the Stern proposals' 'destructive character', saying that "Surely it is reasonable to argue that if one wants to help future generations deal with climate change, the best policies would be those that encouraged economic growth. This would endow future generations with the wealth and superior technologies that could be used to handle whatever comes at them including climate change. (...) So hurrying the process of switching from carbon-based fuels along by boosting energy costs means that humanity will have to delay buying other good things such as clean water, better sanitation, more and better food, and more education." [cite web
November 3, 2006]
The Confederation of British Industries, the British Chambers of Commerce pointed out the dangers to business of additional taxation. [ [http://news.independent.co.uk/business/news/article1940925.ece Business sees red over green tax onslaught - Business News, Business - Independent.co.uk ] ]
"The Business", a British magazine, reported on
November 2, 2006that, according to a leaked United Nations report obtained by the magazine, mitigating climate change could cost up to 5% of global gross domestic product [cite web
title="Leaked UN report shows Stern is wrong on climate"
author= Fraser Nelson
November 2, 2006] . Journalist Fraser Nelson argues that “if the Intergovernmental Panel on Climate Change figures [undermining Stern’s economic rationale] are right, they open up the possibility that the British proposals would cost as much as they save, making them redundant.”
Jerry Taylor of the
Cato Institute, an American libertarian think-tankand climate sceptic organisation, criticized Stern's conclusion, taking a calculation by himself [ [http://www.cato-at-liberty.org/2006/11/03/global-warming-costs-benefits/ Global Warming Costs & Benefits] , Jerry Taylor, "Cato Institute Blog", 3 November 2006] : quote|Stern’s investment advice makes sense only if you think that warming will hammer GDP by 10% a year. You don’t gain much at all from emission cuts, however, if you think GDP will only drop by 5% a year if we do nothing. And if you think warming will only cost the global economy 2% of GDP every year, [...] then Stern’s investment advice is [sheer] lunacy.
cientific consensus is incorrect or does not exist
Martin Livermore, of the
Scientific Alliance, said that "climate is not driven primarily by human use of fossil fuels" and that the money to be spent is unlikely to have much effect: it would be better spent on the world's poor. [ [http://www.gaia-technology.com/sa/campaigns/pressrelease.cfm?pressreleaseID=8&ID=1 Scientific Alliance ] ]
Ruth Lea, Director of the
Centre for Policy Studies, questions if there is scientific consensus about global warming. She alleges that "authorities on climate science say that the climate system is far too complex for modest reductions in one of the thousands of factors involved in climate change (i.e., carbon emissions) to have a predictable effect in magnitude, or even direction." About economic models, upon which Stern relied for his projections, her experience was that forecasting just two or three years ahead was usually wrong. She described the problem of drawing conclusions from combining scientific and economic models as ‘monumentally complex’. She doubted whether international cooperation was really possible. She concluded that she thought that this Review was designed to cloak the motives of a government that wanted some moral justification for increasing taxation on fuels. [cite web
title="Just another excuse for higher taxes"
October 31, 2006]
Two days after publication of the Stern Review,
Nigel Lawsongave a lecture at the Centre for Policy Studies, warning of what he called “eco-fundamentalism” [cite web
title="The Economics and Politics of Climate Change: An Appeal to Reason"
pub=Centre for Policy Studies
November 1, 2006] Nigel Farage, leader of the UK Independence Party, disagreed there was scientific consensus on global warming. At best, he said, there is uncertainty and politicians world-wide are jumping on the ‘green’ bandwagon, but, if they want popular support, they’d better be sure that this is not simply the ‘new witchcraft’. [*cite web
title="A genuine threat or a political bandwagon?"
October 31, 2006] .
tern underestimates damage to natural environments
Professor Bill McGuire of Benfield UCL Hazard Research Centre said that Stern may have greatly underestimated the effects of global warming. cite web
title="Expert reaction to Stern Review"
October 30, 2006]
David Brown and Leo Peskett of the
Overseas Development Institute, a UK think-tankon international development, argued that the key proposals in relation to how to use forests to tackle climate change may prove difficult to implement [ [http://blogs.odi.org.uk/blogs/main/archive/2006/12/05/David_Brown.aspx The challenge of putting Stern’s prescriptions into practice] , David Brown and Leo Peskett, "ODI Weblog", 5 December 2006] : quote|Radical ideas are needed not only at the level of understandings but also of forward strategies. The Stern Review is much stronger on the former than the latter, and leaves a lot of questions unanswered on implementation, particularly the downstream practicalities of bringing avoided deforestation into climate mitigation efforts.
Some economists endorsed the main findings of the Review, while noting that some of the assumptions in the Review's analysis were open to debate. Nobel prize winner
Kenneth Arrowwrote [cite web |url=http://www.project-syndicate.org/commentary/arrow1 |title=Project Syndicate |accessdate=2008-01-07 |format= |work=] quote|Critics of the Stern Review don’t think serious action to limit CO2 emissions is justified, because there remains substantial uncertainty about the extent of the costs of global climate change, and because these costs will be incurred far in the future. However, I believe that Stern’s fundamental conclusion is justified: we are much better off reducing CO2 emissions substantially than risking the consequences of failing to act, even if, unlike Stern, one heavily discounts uncertainty and the future.
In the Economist's Voice, [ [http://www.bepress.com/ev/vol4/iss3/art2/ K.J. Arrow (2007), Global Climate Change: A Challenge to Policy, "Economist's Voice", 4 (3).] ] this is summarised as
Kenneth J. Arrow explains why something must be done to limit global warming even if the Stern Report inadequately discounted future costs.
The central issue in economic debate over the Stern Review concerned the discounting procedure used to evaluate flows of costs and benefits occurring in the future. There are four main reasons commonly proposed for placing a lower value on consumption occurring in the future rather than in the present. [web cite|url=http://johnquiggin.com/wp-content/uploads/2006/12/sternreviewed06121.pdf|title=Stern and the critics on discounting (unpublished)|author=
* future consumption should be discounted simply because it takes place in the future and people generally prefer the present to the future (inherent discounting)
* consumption levels will be higher in the future, so the marginal utility of additional consumption will be lower
* future consumption levels are uncertain
* improved technology of the future will make it easier to address global warming concerns
Debate over the Stern Review initially focused on the first of these points. Previous studies by
William Nordhausand others had adopted inherent discount rates of up to 3 per cent, implying that (other things being equal) an environmental cost or benefit occurring 25 years in the future is worth about half as much as the same benefit today. [ [http://delong.typepad.com/sdj/2006/12/do_unto_others.html http://delong.typepad.com/sdj/2006/12/do_unto_others.html] ] Stern argued that inherent discounting is ethically inappropriate. His view was endorsed by a number of economists including Brad DeLongwho, echoing Frank P. Ramseyand Tjalling Koopmans, wrote “My view--which I admit may well be wrong--of this knotty problem is that we are impatient in the sense of valuing the present and near-future much more than we value the distant future, but that we shouldn't do so.” [ [http://delong.typepad.com/sdj/2006/12/do_unto_others.html http://delong.typepad.com/sdj/2006/12/do_unto_others.html] ] and criticised by others including Hal Varianand Richard Tolwho argue that in a democratic society, the preferences of the majority of people are more important than the arguments of philosophers.
The difference between Stern’s estimates and those of Nordhaus can largely (though not entirely [ [http://ideas.repec.org/p/sgc/wpaper/125.html Tol and Yohe (2007), The Stern Review: A Deconstruction (unpublished)] ] ) be explained by the difference in approach regarding inherent discounting.
Treatment of uncertainty
Uncertainty about future consumption may be addressed either through adjustments to the discount rate or by replacing uncertain flows of consumption with
certainty equivalentflows. Stern adopted the latter approach, but was criticised by Tol and Yohe (2006) for double counting, a claim rejected by Stern (Dietz et al 2007).
While critical of Stern's approach to discounting,
Martin Weitzmanhas presented arguments to suggest that standard discounting procedures are inherently incapable of dealing with extreme, low-probability events, such as the risk of catastrophic climate change. Thus, Weitzman argues, Stern's conclusions are "right for the wrong reasons"
Future consumption will be higher
With increasing average consumption in future, the marginal utility of consumption will decline. The elasticity of the marginal utility of consumption may be interpreted as a measure of aversion to inequality.
Partha Dasgupta[ Partha Dasgupta[http://www.econ.cam.ac.uk/faculty/dasgupta/STERN.pdf Comments on the Stern Review's Economics of Climate Change] December-2006] has criticised the Stern Review for parametric choices that, he argues, are inadequately sensitive to inequality. In subsequent debate, Stern has conceded the case for a higher elasticity, while noting that it would support much more extensive redistribution of income within the current generation (Dietz et al 2007).
As far as discounting is concerned, the effects of improved technology work through increased consumption and do not need to be treated separately. However, specification of an optimal response to climate change will depend on assumptions about improvements in technology and the extent to which such improvements will be induced by policies that increase the cost of emissions.
Both supporters and opponents of Stern's approach have used comparisons with market rates of return on capital to justify their position. [web cite|url=http://johnquiggin.com/wp-content/uploads/2006/12/sternreviewed06121.pdf|title=Stern and the critics on discounting (unpublished)|author=
John Quiggin] The rate chosen by Stern is close to the real interest ratefor government bonds. The higher rates preferred by Stern's critics are closer to the weighted average cost of capitalfor private investment; see the extensive review by Frederick et al. [S.W. Frederick, G. Loewenstein and T. O'Donoghue (2002), Journal of Economic Literature 40(2):351-401] . The difference between the two is determined by the equity premium. There is no generally accepted theory accounting for the observed magnitude of the equity premium and hence no easy way of determining which, if either, approach should be regarded as the appropriate market comparator. [web cite|url=http://johnquiggin.com/wp-content/uploads/2006/12/sternreviewed06121.pdf|title=Stern and the critics on discounting (unpublished)|author= John Quiggin]
tern's later comments
In April 2008 Stern said that the severity of his findings were vindicated by the 2007 IPCC report (which gives stronger warnings than their 2001 report) and admitted that in the Stern Review:“We underestimated the risks ... we underestimated the damage associated with temperature increases ... and we underestimated the probabilities of temperature increases”. [ [http://www.guardian.co.uk/environment/2008/apr/18/climatechange.carbonemissions I underestimated the threat, says Stern] "
The Guardian" ] [ [http://www.ft.com/cms/s/0/d3e78456-0bde-11dd-9840-0000779fd2ac.html?nclick_check=1 Stern takes bleaker view on warming] " Financial Times" ]
In June 2008 Stern said that because global warming is happening faster than predicted the cost to reduce carbon would be even sharper, or about 2% of GDP instead of the 1% in the original report.
Economics of global warming
Politics of global warming
Global warming controversy
World Energy Outlook
Avoiding Dangerous Climate Change
Garnaut Climate Change Review
* [http://www.cambridge.org/us/catalogue/catalogue.asp?isbn=0521700809 The Economics of Climate Change - The Stern Review]
* [http://www.hm-treasury.gov.uk/independent_reviews/stern_review_economics_climate_change/sternreview_index.cfm The UK Government's Treasury web pages about the Stern review]
* [http://www.hm-treasury.gov.uk/independent_reviews/stern_review_economics_climate_change/stern_review_report.cfm Full text of the report]
* [http://www.economist.com/world/international/displaystory.cfm?story_id=8374354 Economist.zoom: How to value a grandchild, Dec 4th 2006]
* [http://www.thefirstpost.co.uk/index.php?menuID=2&subID=1055&p=3 Summary of key findings from the report]
* [http://rabett.blogspot.com/2007/01/stern-gang-eli-has-noted-that-there-are.html "The Stern gang"] , linked index of resources.
In the media
* Nov 2, 2006,
The Economist: [http://www.economist.com/displaystory.cfm?story_id=8108221 Stern warning]
* Nov 6, 2006,
Der Spiegel: [http://www.spiegel.de/international/spiegel/0,1518,447546,00.html The Day the Climate Changed]
* Jan 10, 2007,
BBC: [http://news.bbc.co.uk/1/hi/business/6247371.stm Chrysler Boss says Stern Report is based on dubious economics]
* Jan 26, 2007,
BBC: [http://news.bbc.co.uk/1/hi/sci/tech/6295021.stm Running the rule over Stern's numbers]
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