The Impact of Learning-By-Doing on the Timing and Costs of CO 2 Abatement

A particular ceiling on atmospheric CO2 concentrations can be maintained through a variety of emission pathways. Over the past decade, there has been considerable debate over the characteristics of a least-cost pathway. Some have suggested that a gradual departure from the emissions baseline will be the most cost-effective because it reduces the pressure for premature retirement of the existing capital stock, and it provides valuable time to develop low-cost, low-carbon emitting substitutes. Others counter that a major flaw in analyses that support this line of reasoning is that they ignore learning-by-doing (LBD). In this paper, we examine the impact of LBD on the timing and costs of emissions abatement. With regard to timing, we find that including learning-by-doing does not significantly alter the conclusions of previous studies that treated technology cost as exogenous. The analysis supports the earlier conclusion that for a wide range of stabilization ceilings, a gradual transition away from the 'no policy' emissions baseline is preferable to one that requires substantial near-term reductions. We find that the major impact of including learning-by-doing is on the costs of emission abatement. Depending upon the sensitivity of costs to cumulative experience, LBD can substantially reduce the overall costs of emissions abatement.

Market Exchange Rates or Purchasing Power Parity: Does the Choice Make a Difference to the Climate Debate?

Critics of the Intergovernmental Panel on Climate Change's Special Report on Emission Scenarious claim that the use of market exchange rates rather than purchasing power parity has led to a significant upward bias in projections of greenhouse gas emissions, and hence unrealistically high future temperature. Rather than revisit the debate on the choice of exchange rates, we address a much simpler question: does the choice make a difference when it comes to projecting future temperature change' Employing a computable general equilibrium model designed to examine a variety of issues in the climate debate, we find that the answer is yes, but the difference is only minor.

US Rejection of the Kyoto Protocol: The Impact on Compliance Costs and CO 2 Emissions

Despite the US rejection of the Kyoto Protocol, the meeting of the parties to the UN Framework Convention on Climate Change in July 2001 has increased the likelihood that the Protocol will be ratified. This raises a number of issues concerning mitigation costs, particularly for the buyers and sellers of emission permits. In this paper, we examine how the US decision is likely to affect compliance costs for other Annex B countries during the first commitment period. We also explore the implications for US emissions. Key findings include: 1. Participating OECD countries may experience a decline in mitigation costs, but because of the banking provision contained in the Protocol, the decline may not be as great as some would suggest. 2. If the majority of 'hot air' is concentrated in a small number of countries in Eastern Europe and the former Soviet Union, these countries may be able to organize a sellers' cartel and extract sizable economic rents; and 3. Even in the absence of mandatory emission reduction requirements, US emissions in 2010 may be lower than their business-as-usual baseline because of expectations regarding future regulatory requirements.

Managing the Transition to Climate Stabilization

This paper builds upon recent work by the US Climate Change Science Program (CCSP). Among its products, the CCSP developed new emission projections for the major man-made greenhouse gases, explored the effects of emission limits on the energy system, and calculated the costs of various stabilization constraints to the economy. This paper applies one of the models used for that analysis to explore the sensitivity of the results to three potentially critical factors: the stabilization level, the policy design, and the availability and costs of low- to zero-emitting technologies. The major determinant of costs is likely to be something over which we have little control - Mother Nature. The choice of stabilization level will reflect our understanding of the science of global climate change. We have little control over many of the key bio-geophysical processes which, to a major extent, will determine what constitutes dangerous anthropogenic interference with the climate system. We consider two limits on radiative forcing, corresponding to stabilizing CO2 concentrations at approximately 450 ppmv and 550 ppmv. These levels have been chosen because of the fundamentally different nature of the challenge posed by each. In the case of the lower concentration limit, emission reductions will be required virtually immediately and annual GDP losses to the US could approach 5%. With the higher concentration limit, the pressure for a sharp reduction in near-term emissions is not as great. This offers some potential to reduce GDP losses. Indeed, we find that depending upon the concentration limit, implementing market mechanisms which take advantage of 'where' and 'when' flexibility can markedly reduce GDP losses, perhaps by as much as an order of magnitude. However, for a variety of reasons, our ability to realize such savings may be compromised. One possible impediment relates to the proximity to the target. If the limit is imminent, flexibility will be greatly reduced. The nature of the coalition and our willingness to permit 'borrowing' emission rights from the future will also affect the magnitude of the potential savings. As a result, the reduction in GDP losses from where and when flexibility may turn out to be only a small fraction of what has been previously estimated. Fortunately, the biggest opportunity for managing costs may come from something over which we do have considerable control. We find that investments in climate friendly technologies can reduce GDP losses to the US by a factor of two or more. At present, we have insufficient economically competitive substitutes for high carbon emitting technologies. The development of low- to zero-emitting alternatives will require both a sustained commitment on the part of the public sector upstream in the R&D chain and incentives for the private sector to bring the necessary technologies to the marketplace. Aside from helping to assure that environmental goals are met in an economically efficient manner, climate policy can also serve as an enabler of new technologies. By recognizing the acute shortage of low-cost substitutes, the long lead times required for development and deployment, and the market failures that impede technological progress, climate policy can play an important role in reducing the long-term costs of the transition.

Moving Beyond Concentrations: The Challenge of Limiting Temperature Change

The UN Framework Convention on Climate Change shifted the attention of the policy community from stabilizing greenhouse gas emissions to stabilizing atmospheric greenhouse gas concentrations. While this represents a step forward, it does not go far enough. We find that, given the uncertainty in the climate system, focusing on atmospheric concentrations is likely to convey a false sense of precision. The causal chain between human activity and impacts is laden with uncertainty. From a benefit-cost perspective, it would be desirable to minimize the sum of mitigation costs and damages. Unfortunately, our ability to quantify and value impacts is limited. For the time being, we must rely on a surrogate. Focusing on temperature rather than on concentrations provides much more information on what constitutes an ample margin of safety. Concentrations mask too many uncertainties that are crucial for policy making.

PROGRESS IN ESTIMATING THE MARGINAL COSTS OF GREENHOUSE GAS EMISSIONS

The unjust distributional consequences of climate change, and its potentially negative aggregate effect on economic growth and welfare are two reasons to be concerned about climate change. Our knowledge of the impact of climate change is incomplete. Monetary valuation is difficult and controversial. The effect of other developments on the impacts of climate change is largely speculative. Nonetheless, it can be shown that poorer countries and people are more vulnerable than are richer countries and people. A modest global warming is likely to have a net negative effect on poor economics in hot climates, but may have a positive effect on rich economies in temperate climates. If one counts dollars, the world aggregate impact may be positive. If one counts people, the world aggregate effect is probably negative. For more substantial warming, negative effects become more negative, and positive effects turn negative. The marginal costs of carbon dioxide emissions are uncertain and sensitive to assumptions that partially reflect ethical and methodological positions, but are unlikely to exceed $50 per tonne of carbon. The marginal costs of methane emission are likely to be less than$250/tCH4; the marginal costs of nitrous oxide emissions are probably lower than $7000/tN2O. Global warming potentials, the official manner to trade-off the various greenhouse gases, do not reflect, conceptually or numerically, the real tradeoffs in either a cost-benefit or a cost-effectiveness framework.Impacts of climate change, economic valuation, equity, marginal costs

Synthesis and Assessment Product

This and a companion report constitute one of twenty-one Synthesis and Assessment Products called for in the Strategic Plan for the U.S. Climate Change Science Program. These studies are structured to provide high-level, integrated research results on important science issues with a particular focus on questions raised by decision-makers on dimensions of climate change directly relevant to the U.S. One element of the CCSP's strategic vision is to provide decision support tools for differentiating and evaluating response strategies. Scenario-based analysis is one such tool. The scenarios in this report explore the implications of alternative stabilization levels of anthropogenic greenhouse gases (GHGs) in the atmosphere, and they explicitly consider the economic and technological foundations of such response options. Such scenarios are a valuable complement to other scientific research contained in the twenty-one CCSP Synthesis and Assessment Products. The companion to the research reported here, Global-Change Scenarios: Their Development and Use, explores the broader strategic frame for developing and utilizing scenarios in support of climate decision making