Sources

Why this page

Where a tool holds a rate, a threshold or an emission factor, it prints the publisher of that number and the date the value was read. Where an essay makes a claim, it closes with the reading behind it. All of that sits across twenty pages, which is the right place for it while you are reading one of them and the wrong place if you want to check the whole of it at once. This list is generated from the built pages rather than kept by hand.

The citations are left in the language they were read in.

Instruments

Analyst Desk

• Carried over unchanged from unitguard, which names all four and picks none

  the unitguard case study on keremozdemir.de

CBAM cost and data gap

• Directive (EU) 2023/959 recital 46 and Article 10a(1a) of Directive 2003/87/EC

  eur-lex.europa.euchecked 2026 08 21

• Sectors in scope from 1 January 2026. Cement, iron and steel, aluminium, fertilisers, electricity, hydrogen. European Commission, Carbon Border Adjustment Mechanism

  https://taxation-customs.ec.europa.eu/carbon-border-adjustment-mechanism_en2026 08 21

• De minimis threshold. 50 tonnes, cumulative net mass per importer per calendar year. Regulation (EU) 2025/2083, new Article 2(3a) and Annex VII point 1 of Regulation (EU) 2023/956

  https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=OJ:L_2025020832026 08 21

• Goods outside the threshold. Electricity and hydrogen carry no de minimis relief at any volume. Mayer Brown and KPMG notes on Regulation (EU) 2025/2083

  https://www.mayerbrown.com/en/insights/publications/2025/10/eu-adopts-cbam-simplification-regulation-10-key-amendments-and-challenges-ahead2026 08 21

• Effect of crossing the threshold. All CBAM obligations apply to the whole calendar year, not only to the excess above 50 tonnes. Climate Leadership Council, A Guide to the EU CBAM, April 2026

  https://clcouncil.org/wp-content/uploads/2026/04/A-Guide-to-the-EU-CBAM.pdf2026 08 21

• Chargeable share of embedded emissions. 2.5 per cent in 2026 rising to 100 per cent in 2034, being 100 per cent minus the CBAM factor on free allocation. Directive (EU) 2023/959 recital 46, Article 10a(1a) of Directive 2003/87/EC

  https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32023L09592026 08 21

• Free allocation adjustment mechanism. Certificates are reduced by the free allocation embedded in the good, set out in a dedicated implementing act. Article 31 of Regulation (EU) 2023/956 and Commission Implementing Regulation (EU) 2025/2620

  https://taxation-customs.ec.europa.eu/carbon-border-adjustment-mechanism/cbam-legislation-and-guidance_en2026 08 21

• Sale of certificates begins. 1 February 2027. Article 20 of Regulation (EU) 2023/956 as amended by Regulation (EU) 2025/2083

  https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=OJ:L_2025020832026 08 21

• First annual declaration. 30 September 2027, for imports made in 2026, and 30 September each year after. Article 6 of Regulation (EU) 2023/956 as amended by Regulation (EU) 2025/2083

  https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=OJ:L_2025020832026 08 21

• Quarterly certificate holding. At least 50 per cent of cumulative embedded emissions, reduced from 80 per cent. Article 22 as amended, per Mayer Brown and KPMG notes

  https://kpmg.com/pl/en/insights/law/legal-alert-cbam-mechanism-revised-key-changes-in-eu-regulation-2025-2083.html2026 08 21

• Penalty, authorised declarant. Equal to the EU ETS excess emissions penalty of EUR 100 per tonne under Article 16(3) of Directive 2003/87/EC, indexed under Article 16(4), for each certificate not surrendered. The indexed amount for a given year is not stated in this tool.. Article 26(1) of Regulation (EU) 2023/956

  https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32023R09562026 08 21

• Penalty, importing over the threshold without authorisation. Three to five times the standard penalty, reported as EUR 300 to EUR 500 per tonne, reducible where the threshold is exceeded by no more than 10 per cent. Article 26(2) as amended, per Mayer Brown note

  https://www.mayerbrown.com/en/insights/publications/2025/10/eu-adopts-cbam-simplification-regulation-10-key-amendments-and-challenges-ahead2026 08 21

• Carbon price paid in the country of origin. Deductible. A declarant may claim a reduction in the number of certificates to reflect a carbon price effectively paid, net of any rebate or compensation, with evidence. Article 9 of Regulation (EU) 2023/956

  https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32023R09562026 08 21

• Basis of the certificate price. Set by the Commission from EU ETS auction prices. Quarterly average for 2026 imports, weekly average from 2027. European Commission, CBAM definitive regime, and Implementing Regulation (EU) 2025/2548

  https://taxation-customs.ec.europa.eu/carbon-border-adjustment-mechanism/cbam-definitive-regime_en2026 08 21

• Indicative EU ETS allowance price offered as a starting value. EUR 74.04 per tonne CO2e, monthly average for May 2026. Editable, and not a live price. Initiativ, The Carbon Benchmark in 2026, quoting IndexBox

  https://www.takeinitiativ.com/articles/carbon-benchmark2026 08 21

• Scope extension to downstream goods. Proposed 17 December 2025, procedure 2025/0419(COD), proposed to apply from 2028. Not adopted, not in force, not priced here. European Parliament legislative observatory

  https://oeil.europarl.europa.eu/oeil/en/document-summary?id=18799562026 08 21

Target Path

• Science Based Targets initiative, Absolute Contraction Approach. The binding text is the SBTi Corporate Near-Term Criteria, version 5.3.1, April 2026

  sciencebasedtargets.orgchecked 2026 08 25

Essays

The evolution of cooperation

• The first tournament: fourteen submitted programs plus a random one, two hundred rounds per pairing, payoffs of five, three, one and zero for temptation, reward, punishment and sucker. Tit for tat, submitted by Anatol Rapoport, finished first. The tournament was run five times to smooth out the random element. Anatol Rapoport, Darryl A. Seale and Andrew M. Colman, Is Tit for Tat the Answer? On the Conclusions Drawn from Axelrod's Tournaments, PLOS ONE 10(7), 2015. Corroborated by Leigh Tesfatsion's course notes on the Axelrod tournaments. Checked 2026 08 21.

  journals.plos.org/plosone/article?id=10.1371/journal.pone.0134128faculty.sites.iastate.edu

• The second tournament: sixty two entries, sixty three programs including random, entrants knowing the results of the first. Match length was probabilistic rather than fixed, with a chance of 0.00346 of ending after any given round. Tit for tat, entered again by Rapoport, won again. Rapoport, Seale and Colman, as above, for the entry count and the probabilistic match length. The ending probability of 0.00346 and Rapoport's authorship are given in the Theory, Evolution and Games Group summary of the tournaments. Checked 2026 08 21.

  egtheory.wordpress.com/2015/03/02/ipd

• The ecological tournament: one thousand generations, in which the number of copies of a strategy at the start of a generation was set equal to the total payoff that strategy won in the previous one. Tit for tat rose. Leigh Tesfatsion, Notes on Axelrod's Iterated Prisoner's Dilemma Tournaments, Iowa State University. Checked 2026 08 21.

  faculty.sites.iastate.edu/tesfatsi/archive/econ308/tesfatsion/axeltmts.pdf

• The qualification: the authors argue that the success of tit for tat in Axelrod's tournaments owed much to the presence of a small number of weak programs, so that conclusions drawn from the tournaments are conditional on the pool of entrants rather than general. Rapoport, Seale and Colman, Is Tit for Tat the Answer? On the Conclusions Drawn from Axelrod's Tournaments, PLOS ONE 10(7), 2015. Checked 2026 08 21.

  journals.plos.org/plosone/article?id=10.1371/journal.pone.0134128

The market for lemons

• The paper itself, and the numerical example in which buyers value cars at three halves of the owner's valuation and quality is spread evenly, so that no price above zero is consistent with itself. George A. Akerlof, The Market for “Lemons”: Quality Uncertainty and the Market Mechanism, The Quarterly Journal of Economics, volume 84, number 3, August 1970, pages 488 to 500. DOI 10.2307/1879431. Bibliographic details confirmed at. The setup, a buyer willing to pay three halves of the seller's valuation, quality distributed uniformly, and a unique equilibrium price of zero at which no car is sold, is set out in George Georgiadis, Information Economics, Module 14: Adverse Selection, Kellogg School of Management. Checked 2026 08 21.

  doi.org/10.2307/1879431en.wikipedia.org/wiki/The_Market_for_Lemonskellogg.northwestern.edu/faculty/georgiadis/Teaching/Ec515_Module14.pdf

• Akerlof's own account of the rejections: the American Economic Review and the Review of Economic Studies declined the paper on the ground that they did not publish work on subjects of such triviality, and a referee at the Journal of Political Economy held that if the paper were correct then no goods could be traded. George A. Akerlof, Writing the “The Market for ‘Lemons’”: A Personal and Interpretive Essay, published by the Nobel Foundation, 2001. Read through the summary at. Checked 2026 08 21.

  nobelprize.org/prizes/economic-sciences/2001/akerlof/articleequitablegrowth.org

• The 2001 Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel was awarded jointly to George A. Akerlof, A. Michael Spence and Joseph E. Stiglitz for their analyses of markets with asymmetric information. The Nobel Foundation, prize summary for 2001. Checked 2026 08 21.

  nobelprize.org/prizes/economic-sciences/2001/summary

• Warranties, vehicle history reports, brand reputation and licensing are the institutions usually named as market answers to the problem, rather than statutory ones. David R. Henderson, editor, The Concise Encyclopedia of Economics, biography of George Akerlof, Library of Economics and Liberty. Checked 2026 08 21.

  econlib.org/library/Enc/bios/Akerlof.html

Who actually pays a tax

• Employers in a Greek natural experiment compensated new workers for higher employer contributions but not for higher employee contributions, so the statutory split affected the economic outcome. Emmanuel Saez, Manos Matsaganis and Panos Tsakloglou, Earnings Determination and Taxes: Evidence From a Cohort-Based Payroll Tax Reform in Greece, Quarterly Journal of Economics 127(1), 2012, pages 493 to 533. Working version read at. Checked 2026 08 21.

  academic.oup.com/qje/article-abstract/127/1/493/1832830eml.berkeley.edu

• Value added tax pass through is asymmetric: increases are passed to consumers several times more fully than cuts are, and the gap persists for years. The same survey collects evidence that who remits a tax can affect its economic incidence. Youssef Benzarti, Tax Incidence Anomalies, NBER Working Paper 32819, August 2024. Checked 2026 08 21.

  nber.org/system/files/working_papers/w32819/w32819.pdf

• The Congressional Budget Office estimates that about 58 per cent of the additional burden of a broad increase in the payroll tax rate falls on employees in the short run, with the rest borne by capital and other factors. Dorian Carloni, Revisiting the Extent to Which Payroll Taxes Are Passed Through to Employees, CBO Working Paper 2021 06, June 2021. Checked 2026 08 21.

  cbo.gov/publication/57089

Why the future is cheap

• The parameters in the table. Stern: pure time preference 0.1 per cent, elasticity of marginal utility 1.0, growth 1.3 per cent, giving a consumption discount rate of 1.40 per cent. Nordhaus: pure time preference 3.0 per cent, the same elasticity and growth, giving 4.30 per cent. The same paper states that a given loss of consumption a hundred years from now is seventeen times smaller at 4.3 per cent than at 1.4 per cent. Lawrence H. Goulder and Roberton C. Williams III, The Choice of Discount Rate for Climate Change Policy Evaluation, NBER Working Paper 18301, 2012. Checked 2026 08 21.

  nber.org/system/files/working_papers/w18301/w18301.pdf

• The same two figures, 1.4 per cent for Stern as 1.3 per cent of productivity growth plus 0.1 per cent for the risk of extinction, and 4.3 per cent for Nordhaus, with the framing of the disagreement as ethical rather than technical. The CORE Econ Project, The Economy, microeconomics, section 9.5, Discounting, external effects, and the future of the planet. Checked 2026 08 21.

  books.core-econ.org

• The Stern Review's own parameters: a pure rate of time preference of 0.1 per cent per year, justified by the risk of extinction, and an elasticity of marginal utility of one. House of Commons Library, The Stern Review and the discount rate, Standard Note SN/EP/4739. Checked 2026 08 21.

  researchbriefings.files.parliament.uk/documents/SN04739/SN04739.pdf

• Nordhaus's own statement of his objection: that the Stern Review's conclusions depend decisively on the assumption of a near zero time discount rate combined with a specific utility function, and would not survive the substitution of assumptions consistent with market real interest rates and savings rates. William D. Nordhaus, A Review of the Stern Review on the Economics of Climate Change, Journal of Economic Literature, volume 45, number 3, 2007, pages 686 to 702. Checked 2026 08 21.

  aeaweb.org/articles?id=10.1257/jel.45.3.686

• The regulatory figure: the November 2023 revision of Circular A-4 adopts a 2.0 per cent real social rate of time preference for near term analysis, updated every three years, with a schedule of declining rates for long horizons reaching 1.1 per cent for the years 2164 to 2172. Office of Management and Budget, Circular No. A-4 discount rate history and appendix, 9 November 2023. Checked 2026 08 21.

  whitehouse.gov/wp-content/uploads/2023/11/CircularA-4DiscountHistory.pdf

Simulations

Diffusion, and the shape it runs through

• The small world construction used here, in which a ring lattice is rewired with a small probability. The paper reports that such networks are highly clustered like lattices yet have small characteristic path lengths like random graphs, and that infectious diseases spread more easily in them than in regular lattices. Duncan J. Watts and Steven H. Strogatz, Collective dynamics of 'small-world' networks, Nature 393(6684), 4 June 1998, pages 440 to 442. Checked 2026 08 22.

  nature.com/articles/30918

• The threshold rule and the reversal it produces. The paper argues that complex contagions require social affirmation from multiple sources, that long ties can hinder rather than help their diffusion as the adoption threshold rises, and that what matters is the width of the bridges across a network rather than the length of individual ties. Damon Centola and Michael Macy, Complex Contagions and the Weakness of Long Ties, American Journal of Sociology 113(3), 2007, pages 702 to 734. Checked 2026 08 22.

  journals.uchicago.edu/doi/abs/10.1086/521848

• The scale free graph is built by preferential attachment, in which each arriving node connects to existing nodes with probability proportional to how many connections they already have. Albert-László Barabási and Réka Albert, Emergence of Scaling in Random Networks, Science 286(5439), 1999, pages 509 to 512. Checked 2026 08 22.

  science.org/doi/10.1126/science.286.5439.509

Segregation without a bigot

• The paper that introduced the model, with both a one dimensional line of neighbours and the two dimensional board used here. In the board version a household counts the eight surrounding squares, demands that at least half of its neighbours be of its own kind, and moves to the nearest vacancy that satisfies it. Schelling reports that these mild demands produce clusters in which the great majority of neighbours are alike, and writes that there is no simple correspondence between individual incentive and collective result. Thomas C. Schelling, Dynamic Models of Segregation, The Journal of Mathematical Sociology 1(2), 1971, pages 143 to 186. Full text read at. Checked 2026 08 22.

  tandfonline.com/doi/abs/10.1080/0022250X.1971.9989794suz.uzh.ch

The jam

• Vehicles were driven around a circuit, starting evenly spaced and moving uniformly, with no bottleneck present. Below a critical density the uniform flow held. Above it the flow became unstable, a tiny fluctuation grew, and a jam cluster appeared and propagated backward like a solitary wave with the same speed as a jam cluster on a highway. The authors conclude that a bottleneck is only a trigger and not the essential origin of a traffic jam, and present the work as the first experimental evidence that a jam is a collective phenomenon. Yuki Sugiyama, Minoru Fukui, Macoto Kikuchi, Katsuya Hasebe, Akihiro Nakayama, Katsuhiro Nishinari, Shin-ichi Tadaki and Satoshi Yukawa, Traffic jams without bottlenecks: experimental evidence for the physical mechanism of the formation of a jam, New Journal of Physics 10, 2008, article 033001. Checked 2026 08 22.

  iopscience.iop.org/article/10.1088/1367-2630/10/3/033001

The pile

• The paper that introduced the model and the idea of self organised criticality: dynamical systems with spatial degrees of freedom naturally evolve into a self organised critical state, which the authors connect to flicker noise and to the origin of fractal structures. Per Bak, Chao Tang and Kurt Wiesenfeld, Self-organized criticality: An explanation of the 1/f noise, Physical Review Letters 59(4), 27 July 1987, page 381. Checked 2026 08 22.

  journals.aps.org/prl/abstract/10.1103/PhysRevLett.59.381

The recommender

• The update rule is a bounded confidence model: an agent takes account only of the opinions within a confidence interval of its own, and the paper investigates how the width of that interval decides whether a population reaches consensus, splits or fragments. Rainer Hegselmann and Ulrich Krause, Opinion Dynamics and Bounded Confidence: Models, Analysis and Simulation, Journal of Artificial Societies and Social Simulation 5(3), article 2, 2002. Checked 2026 08 22.

  jasss.org/5/3/2.html

• The entropy of the choice environment is Shannon's entropy of the distribution of what is served, normalised by the entropy of the flat distribution over the same bins. Claude E. Shannon, A Mathematical Theory of Communication, The Bell System Technical Journal 27, 1948, pages 379 to 423 and 623 to 656. Full text read at. Checked 2026 08 22.

  doi.org 10.1002/j.1538-7305.1948.tb01338.xpeople.math.harvard.edu

• The three constructs and the reasons for wanting them. Kerem Özdemir, The agent was never alone: SIMEA, a working note.

  keremozdemir.de/note-simea.html

Games

Matching Pennies

• Mixed strategies in a real conflict. Mark Walker and John Wooders, Minimax Play at Wimbledon, American Economic Review 91(5), December 2001, pages 1521 to 1538. Author's copy of the paper. Read 2026 08 21.

  https://www.johnwooders.com/papers/Wimbledon.pdf

• How well people generate random sequences. Alice Wong, Gabriel Merholz and Uri Maoz, Characterizing human random sequence generation in competitive and non competitive environments using Lempel Ziv complexity, Scientific Reports 11, article 20662, 2021. Read 2026 08 21.

  https://www.nature.com/articles/s41598-021-99967-6

• Equilibrium in mixed strategies. John F. Nash, Equilibrium Points in n Person Games, Proceedings of the National Academy of Sciences 36(1), 1950, pages 48 and 49. Read 2026 08 21.

  https://pmc.ncbi.nlm.nih.gov/articles/PMC1063129/

The Beauty Contest

• The newspaper competition. John Maynard Keynes, The General Theory of Employment, Interest and Money, 1936, chapter 12, The State of Long Term Expectation. The German and Turkish renderings here are my own. Read 2026 08 21.

  https://www.marxists.org/reference/subject/economics/keynes/general-theory/ch12.htm

• The experiment. Rosemarie Nagel, Unraveling in Guessing Games: An Experimental Study, American Economic Review 85(5), 1995, pages 1313 to 1326. Read 2026 08 21.

  https://extranet.parisschoolofeconomics.eu/docs/guesnerie-roger/nagel95.pdf

• Equilibrium. John F. Nash, Equilibrium Points in n Person Games, Proceedings of the National Academy of Sciences 36(1), 1950, pages 48 and 49. Read 2026 08 21.

  https://pmc.ncbi.nlm.nih.gov/articles/PMC1063129/

The Commons

• The finding. The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel 2009, press release of 12 October 2009, on Elinor Ostrom. Read 2026 08 21. The German and Turkish renderings are my own.

  https://www.nobelprize.org/prizes/economic-sciences/2009/press-release/

• The design principles and the reading of Hardin. Economic Governance, scientific background on the 2009 prize, Royal Swedish Academy of Sciences. Read 2026 08 21. The German and Turkish renderings are my own.

  https://www.nobelprize.org/uploads/2018/06/advanced-economicsciences2009.pdf

The Long Game

• The tournament. Robert Axelrod, Effective Choice in the Prisoner's Dilemma, Journal of Conflict Resolution 24(1), 1980, pages 3 to 25.

  https://doi.org/10.1177/002200278002400101

• The ecological run, where the winners reproduce. Robert Axelrod and William D. Hamilton, The Evolution of Cooperation, Science 211(4489), 1981, pages 1390 to 1396.

  https://doi.org/10.1126/science.7466396

The Stag Hunt

• The hunt itself. Jean Jacques Rousseau, A Discourse on the Origin of Inequality (1754), second part, in the English translation by G. D. H. Cole, 1913. The German and Turkish renderings here are my own. Read 2026 08 21.

  https://www.marxists.org/reference/subject/economics/rousseau/inequality/ch02.htm

• Equilibrium point. John F. Nash, Equilibrium Points in n Person Games, Proceedings of the National Academy of Sciences 36(1), 1950, pages 48 and 49. Read 2026 08 21.

  https://pmc.ncbi.nlm.nih.gov/articles/PMC1063129/

The Ultimatum

• The experimental record. Hessel Oosterbeek, Randolph Sloof and Gijs van de Kuilen, Cultural Differences in Ultimatum Game Experiments: Evidence from a Meta Analysis, Experimental Economics 7(2), 2004, pages 171 to 188. Working paper text. Read 2026 08 21.

  https://econwpa.ub.uni-muenchen.de/econ-wp/exp/papers/0401/0401003.pdf

• The first experiment. Werner Güth, Rolf Schmittberger and Bernd Schwarze, An experimental analysis of ultimatum bargaining, Journal of Economic Behavior and Organization 3(4), 1982, pages 367 to 388. Read 2026 08 21.

  https://econpapers.repec.org/RePEc:eee:jeborg:v:3:y:1982:i:4:p:367-388

• Equilibrium and backward induction. John F. Nash, Equilibrium Points in n Person Games, Proceedings of the National Academy of Sciences 36(1), 1950, pages 48 and 49. Read 2026 08 21.

  https://pmc.ncbi.nlm.nih.gov/articles/PMC1063129/

Case studies

target-path, case study

• Minimum linear annual reduction of 4.2 percent for near term Scope 1 and 2 targets aligned with 1.5°C, under the absolute contraction approach. Science Based Targets initiative. The binding text is the SBTi Corporate Near-Term Criteria, version 5.3.1, April 2026.

  sciencebasedtargets.orgRead 2026 08 25

unitguard, case study

• Methane, GWP over one hundred years, 25. IPCC Fourth Assessment Report, Working Group I, chapter 2, table 2.14.

  ipcc.ch/report/ar4/wg1Read 2026 08 25

• Methane, GWP over one hundred years, 28, the value without climate carbon feedbacks. IPCC Fifth Assessment Report, Working Group I, chapter 8, table 8.7.

  ipcc.ch/report/ar5/wg1Read 2026 08 25

• Methane, GWP over one hundred years, 27.0 for non fossil methane and 29.8 for fossil methane. IPCC Sixth Assessment Report, Working Group I, chapter 7, table 7.15.

  ipcc.ch/report/ar6/wg1/chapter/chapter-7Read 2026 08 25