Bob van der Zwaan

The urgency of the development of CO2 capture from ambient air

CO2 capture and storage (CCS) has the potential to develop into an important tool to address climate change. Given society’s present reliance on fossil fuels, widespread adoption of CCS appears indispensable for meeting stringent climate targets. We argue that for conventional CCS to become a successful climate mitigation technology—which by necessity has to operate on a large scale—it may need to be complemented with air capture, removing CO2 directly from the atmosphere. Air capture of CO2 could act as insurance against CO2 leaking from storage and furthermore may provide an option for dealing with emissions from mobile dispersed sources such as automobiles and airplanes.

The Impact of Uncertainty in Climate Targets and CO 2 Storage Availability on Long-Term Emissions Abatement

A major characteristic of our global interactive climate-energy system is the large uncertainty that exists with respect to both future environmental requirements and the means available for fulfilling these. Potentially, a key technology for leading the transition from the current fossil fuel-dominated energy system to a more sustainable one is carbon dioxide capture and storage. Uncertainties exist, however, concerning the large-scale implementability of this technology, such as related to the regional availability of storage sites for the captured CO2. We analyze these uncertainties from an integrated assessment perspective by using the bottom-up model TIAM-ECN and by studying a set of scenarios that cover a range of different climate targets and technology futures. Our study consists of two main approaches: (1) a sensitivity analysis through the investigation of a number of scenarios under perfect foresight decision making and (2) a stochastic programming exercise that allows for simultaneously considering a set of potential future states-of-the-world. We find that, if a stringent climate (forcing) target is a possibility, it dominates the solution: if deep CO2 emission reductions are not started as soon as possible, the target may become unreachable. Attaining a stringent climate target comes in any case at a disproportionally high price, which indicates that adaptation measures or climate damages might be preferable to the high mitigation costs such a target implies.

Evaluating Uncertain CO2 Abatement over the Very Long Term

Climate change research with the economic methodology of cost–benefit analysis is challenging because of valuation and ethical issues associated with the long delays between CO2 emissions and much of their potential damages, typically of several centuries. The large uncertainties with which climate change impacts are known today and the possibly temporary nature of some envisaged CO2 abatement options exacerbate this challenge. For example, potential leakage of CO2 from geological reservoirs, after this greenhouse gas has been stored artificially underground for climate control reasons, requires an analysis in which the uncertain climatic consequences of leakage are valued over many centuries. We here present a discussion of some of the relevant questions in this context and provide calculations with the top–down energy-environment-economy model DEMETER. Given the long-term features of the climate change conundrum as well as of technologies that can contribute to its solution, we considered it necessary extending DEMETER to cover a period from today until the yearxa03000, a time span so far hardly investigated with integrated assessment models of climate change.

Technology Diffusion and the Stability of Climate Coalitions

Free-riding is a major problem for international climate policy. A country can take advantage of other countries emission reduction without contributing to abatement policies itself. Game theory suggests that issue linkage may help to overcome free-riding. Earlier studies suggest that if negotiations on greenhouse gas emission reduction are coupled to negotiation on technology transfer, the incentives to co-operate increase. This study confirms that finding. A country has less reason to free-ride if free-riding implies that the countries loses access to desirable, foreign technologies. We also show that, in many cases, it hurts to deny another country access to domestic technologies, if that country retaliates by withholding its technologies. We further show that the losses of withholding abatement technologies are small relative to the gains of free-riding. So, linking greenhouse gas emission reduction with technology diffusion helps to deter free-riding, but only a little bit, and only if the two issues are automatically linked.

Negotiating climate change as a social situation

This paper applies the theory of social situations to international environmental agreements on greenhouse gas emission reduction. The usual pessimism on the size of stable coalitions among world regions is challenged for two alternative cases, namely by introducing farsightedness and by introducing coalitional moves with commitment. This is an extension of stability in the cartel game, where a cartel symbolises a coalition among world regions for reducing greenhouse gas emissions. It is a special case of the commitment situation, which has been proposed in the theory of social situations. The results are obtained by restricting the move rules in the game among world regions.

Climate Uncertainty and the Necessity to Transform Global Energy Supply

This paper analyses the policy relevance of the dominant uncertainties in our current scientific understanding of the terrestrial climate system, and provides further evidence for the need to radically transform - this century - our global infrastructure of energy supply, given the global average temperature increase as a result of anthropogenic carbon dioxide emissions. We investigate the effect on required CO2 emission reduction efforts, both in terms of how much and when, of our uncertain knowledge today of the climate sensitivity to a doubling in them atmospheric CO2 concentration. Also the roles of carbon-free energy and energy savings, and their evolutions over time, are researched, as well as their dependence on some of our characteristic modelling features. We use a top-down model in which there are two competing energy sources, fossil and non-fossil. Technological change is represented endogenously through learning curves, and modest but non-zero demand exists for the relatively expensive carbon-free energy resource.

Discounting and Sustainability in Integrated Assessment Models

Most currently employed Integrated Assessment Models are of a dynastic nature, commonly assuming a fixed relation between pure time preference, economic growth and interest rate. This rigid relation has led to much debate on which level of discounting to adopt. Especially the quantitative results of Integrated Assessment Models have been subject to controversy because of their strong sensitivity on future discounting. Many economic analysts advocate employing a descriptive time preference, based on historic data, which usually represents an approximate efficient use of environmental resources. Others encourage assuming a prescriptive time discounting, allowing them - by taking low discount values - to model a sustainable use of environmental services. This paper argues that, although a fixed time preference relation might be convenient for economic analysis, such a supposition can be misleading. By avoiding a rigid discounting relation, the descriptive-prescriptive controversy can be avoided. It is concluded that dynastic Integrated Assessment Models are in many respects inappropriate for providing policy makers with quantitative figures about the costs of carbon dioxide emissions, and their desirable reduction levels. In contrast, Overlapping Generations models, allowing the use of a flexible discounting relation, are suitable for designing a broad class of policy instruments. With the Integrated Assessment Model ALICE 2.0, it is shown how various assumptions on demographic change and public institutions can affect the interest rate, thereby influencing the desired optimal greenhouse gas emission reductions. It is recommended that economic modelling intensify attempting to establish both efficient and sustainable resource use. The discount rate should be treated as an endogenous variable, rather than an exogenous parameter characterising a central planner.