Tag Archives: Externality

Mortality Externalities of CO2-Emissions

In the Quarterly Journal of Economics (137, 4), a group of authors estimates that

the mean global increase in mortality risk due to climate change, accounting for adaptation benefits and costs, is valued at roughly 3.2% of global GDP in 2100 under a high-emissions scenario. Notably, today’s cold locations are projected to benefit, while today’s poor and hot locations have large projected damages. Finally, our central estimates indicate that the release of an additional ton of CO2 today will cause mortality-related damages of $36.6 under a high-emissions scenario, with an interquartile range accounting for both econometric and climate uncertainty of [−$7.8, $73.0].

“Wirtschaftspolitik in Corona-Zeiten (Economic Policy in Times of Corona),” FuW, 2020

Finanz und Wirtschaft, December 9, 2020. PDF.

  • Economic policy is not about GDP growth. It’s about welfare.
  • Externalities are key. Infection externalities don’t go away by calling for responsible behavior. Infection externalities can turn positive.
  • Keeping worthy companies or networks alive does not require government intervention, unless capital markets don’t work.
  • To judge the right amount of burden sharing is beyond economics. But economics gives some clues: In an ideal world, idiosyncratic risk exposure would be insured while in second best, taxes and subsidies achieve only part of that. The data show that trade-offs between public health and economic activity are less severe than sometimes argued.

Nordhaus on Climate Change

In his Nobel lecture (reprinted in the June issue of the American Economic Review), William Nordhaus concludes that we should focus on four goals:

First, people around the world need to understand and accept … Those who understand the issue must speak up and debate contrarians who spread false and tendentious reasoning. …

Second, nations must establish policies that raise the price of CO2 and other greenhouse-gas emissions. …

Moreover, we need to ensure that actions are global and not just national or local. … The best hope for effective coordination is a climate club, which is a coalition of nations that commit to strong steps to reduce emissions along with mechanisms to penalize countries who do not participate. …

Finally, … [d]eveloping economical low-carbon technologies will lower the cost of achieving our climate goals. Moreover, if other policies fail, low-carbon technologies are the last refuge—short of the salvage therapy of geoengineering—for achieving our climate goals or limiting the damage.

Negative Value Added of Switzerland’s Agricultural Sector

Farmers in Switzerland receive about CHF 2.7 billion in direct financial support annually. Total financial support by the federal and cantonal governments equals more than CHF 4 billion. But according to a report published by Zurich based think tank Avenir Suisse, this financial support constitutes just a minor part of the transfers from society at large to farmers, due to explicit and implicit subsidies, privileges, and—most importantly—negative externalities.

A list of privileges compiled by Avenir Suisse.

Avenir Suisse estimates the value added of Swiss agriculture to be hugely negative.

Die heutige Schweizer Landwirtschaft resultiert in einer negativen Wertschöpfung von minus 15,8 Mrd. Fr. pro Jahr. Damit kostet sie uns umgerechnet rund 1,8 Mio. Fr. pro Stunde.

In the NZZ, Nicole Rütti reports.

“Regulierung und Wettbewerb (Regulation and Competition),” FuW, 2017

Finanz und Wirtschaft, December 13, 2017. PDF. Ökonomenstimme, December 15, 2017. HTML.

  • Regulation is about aligning private and social trade-offs.
  • When banks cause negative externalities, good regulatory interventions increase banks’ costs.
  • Externalities may differ across countries, so nothing suggests that regulation induced costs should be the same internationally.

Pecuniary Externalities and Aggregate Demand Externalities

In Econometrica, Emmanuel Farhi and Iván Werning neatly summarize how their work on demand externalities fits in the literature.

… pecuniary externalities, which were first shown to arise when a simple friction, market incompleteness, is introduced into the Arrow–Debreu framework (see, e.g., Hart (1975), Stiglitz (1982), Geanakoplos and Polemarchakis (1985), Geanakoplos, Magill, Quinzii, and Dreze (1990)). The logic is as follows. When asset markets are incomplete and there is more than one commodity, a redistribution of asset holdings generically induces relative price changes in spot markets, in each state of the world. These relative price changes, in turn, affect the spanning properties of the limited assets that are available, potentially improving insurance. Such a pecuniary externality is not internalized by private agents. As a result, the equilibrium is generically constrained inefficient: it can be improved upon by interventions in the existing financial markets. Similar results obtain in economies with borrowing constraints that depend on prices of goods and assets, or when contracting is constrained by private information (see, e.g., Greenwald and Stiglitz (1986)). … [Other work in this literature includes Caballero and Krishnamurthy (2001), Lorenzoni (2008), Farhi, Golosov, and Tsyvinski (2009), Bianchi and Mendoza (2010), Jeanne and Korinek (2010), Bianchi (2011), Korinek (2011), Davilla (2011), Stein (2012), Korinek (2012a, 2012b), Jeanne and Korinek (2013), Woodford (2011).]

… Instead of pecuniary externalities, our theory emphasizes aggregate demand externalities. In addition to providing a new foundation for macroprudential policies, our framework, focusing on monetary policy and nominal rigidities, is well posed for the joint study of monetary and macroprudential policy.

… using a perturbation argument similar in spirit to that in Geanakoplos and Polemarchakis (1985), we show that equilibria that are not first best can be improved upon by interventions in financial markets, except in non-generic knife-edge cases. … In [the pecuniary externality] literature, the key frictions lie in financial markets themselves; in our baseline model, we assume complete markets. Pecuniary externalities rely on price movements; in our framework, price rigidities tend to negate such effects. Our results are instead driven by aggregate demand externalities that arise from nominal rigidities.

“Politico-Economic Equivalence,” RED, 2015

Review of Economic Dynamics 18(4), October 2015, with Martín Gonzalez-Eiras. PDF.

Traditional “economic equivalence” results, like the Ricardian equivalence proposition, define equivalence classes over exogenous policies. We derive “politico-economic equivalence” conditions that apply in environments where policy is endogenous and chosen sequentially. A policy regime and a state are equivalent to another such pair if both pairs give rise to the same allocation in politico-economic equilibrium. The equivalence conditions help to identify factors that render institutional change non-neutral and to construct politico-economic equilibria in new policy regimes. We exemplify their use in the context of several applications, relating to social security reform, tax-smoothing policies and measures to correct externalities.