The Environment and Directed Technical Change

The Environment and Directed Technical Change

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The Environment and Directed Technical Change

dc.contributor.author	Hemous, David
dc.contributor.author	Bursztyn, Leonardo
dc.contributor.author	Aghion, Philippe
dc.contributor.author	Acemoglu, Daron
dc.date.accessioned	2010-11-15T15:54:55Z
dc.date.issued	2009
dc.identifier.citation	Acemoglu, Daron, Philippe Aghion, Leonardo Bursztyn, and David Hemous. 2009. The environment and directed technical change. Unpublished working paper, Harvard University, July 6, 2009.	en_US
dc.identifier.uri	http://nrs.harvard.edu/urn-3:HUL.InstRepos:4554221
dc.description.abstract	This paper introduces endogenous and directed technical change in a growth model with environmental constraints and limited resources. A unique final good is produced by combining inputs from two sectors. One of these sectors uses "dirty" machines and thus creates environmental degradation. Research can be directed to improving the technology of machines in either sector. We characterize dynamic tax policies that achieve sustainable growth or maximize intertemporal welfare, as a function of structural characteristics of the economy, in particular the degree of substitutability between clean and dirty inputs, environmental and resource stocks, and cross-country technological spillovers. First, we find that factoring in directed technical change: (i) increases the cost of delaying intervention, particularly when the inputs are highly substitutable; (ii) calls for the use of profit taxes or other instruments to direct innovation, in addition to the input (carbon) tax emphasized in the literature. Second, we show that: (i) in the case where the inputs are sufficiently substitutable, sustainable long-run growth can be achieved with temporary taxation of dirty innovation and production; (ii) the sooner and the stronger is the policy response, the shorter is the slow growth transition phase; (iii) the use of an exhaustible resource in dirty input production helps the switch to clean innovation under laissez-faire when the two inputs are substitutes. Third, we find that under reasonable parameter values (corresponding to those used in existing models with exogenous technology) and with sufficient substitutability between inputs, it is optimal to redirect technical change towards clean technologies immediately. Finally, in a two-country extension of the baseline model where: (a) the two inputs are sufficiently substitutable in both countries; (b) dirty input production in both countries depletes the global environmental stock; (c) the South imitates technologies invented in the North, we show that taxing dirty innovation and production in the North only may be sufficient to avoid a global disaster, but international trade increases the need for global policy coordination.	en_US
dc.description.sponsorship	Economics	en_US
dc.language.iso	en_US	en_US
dc.relation.isversionof	http://www.economics.harvard.edu/faculty/aghion/papers_aghion	en_US
dash.license	OAP
dc.subject	innovation	en_US
dc.subject	directed technological change	en_US
dc.subject	exhaustible resources	en_US
dc.subject	environment	en_US
dc.title	The Environment and Directed Technical Change	en_US
dc.type	Research Paper or Report	en_US
dc.description.version	Author's Original	en_US
dash.depositing.author	Aghion, Philippe
dc.date.available	2010-11-15T15:54:55Z