Climate change impacts on irrigation water requirements: Effects of mitigation, 1990–2080

Potential changes in global and regional agricultural water demand for irrigation were investigated within a new socio-economic scenario, A2r, developed at the International Institute for Applied Systems Analysis (IIASA) with and without climate change, with and without mitigation of greenhouse gas emissions. Water deficits of crops were developed with the Food and Agriculture Organization (FAO)–IIASA Agro-ecological Zone model, based on daily water balances at 0.5° latitude × 0.5° longitude and then aggregated to regions and the globe. Future regional and global irrigation water requirements were computed as a function of both projected irrigated land and climate change and simulations were performed from 1990 to 2080. Future trends for extents of irrigated land, irrigation water use, and withdrawals were computed, with specific attention given to the implications of climate change mitigation. Renewable water-resource availability was estimated under current and future climate conditions. Results suggest that mitigation of climate change may have significant positive effects compared with unmitigated climate change. Specifically, mitigation reduced the impacts of climate change on agricultural water requirements by about 40%, or 125–160 billion m³ (Gm³) compared with unmitigated climate. Simple estimates of future changes in irrigation efficiency and water costs suggest that by 2080 mitigation may translate into annual cost reductions of about 10 billion US$.     

Do market prices aggregate information about macroeconomic uncertainty (or risk)?

This article examines several economic variables that represent either confidence in future economic conditions or the degree of risk/uncertainty about future conditions in order to determine which contain more information about future employment and output. Some of these variables are prices, while others are from surveys. Causality tests, historical decompositions within a VAR and out-of-sample forecasts are among the tools used. This article concludes that monthly stock returns contain much more information about future economic conditions than the other variables. The spread between Moody’s BAA and AAA bonds, the spread between the constant maturity 10-year government bond and the federal funds rate, as well as uncertainty in future economic conditions as measured by the Federal Reserve Bank of Philadelphia’s Business Outlook Survey also provide information about future economic conditions. Notably, this article finds that monthly stock returns contain more information about future economic conditions than does the vix and that variables based on market prices provide more information than survey data. This result provides some support for the notion that market prices aggregate information.     

Adaptation,mitigation and risk-taking in climate policy

The future consequences of climate change are highly uncertain and estimates of economic damages differ widely. Governments try to cope with these risks by investing in mitigation and adaptation measures. In contrast to most of the existing literature, we explicitly model the decision of risk averse governments on mitigation and adaptation policies. We also consider the interaction of the two strategies in presence of uncertainty. Mitigation efforts of a single country trigger crowding out as other countries will reduce their mitigation efforts. This may even lead to lower mitigation on the global scale. In contrast, a unilateral commitment to large adaptation efforts benefits the single country and can reduce the global risk from climate change at the expense of other countries.     

RETAIL PRICE REGULATION AND THE OPTION TO DELAY

ABSTRACT ** :  This paper examines a two-period model of an investment decision in a network industry characterized by demand uncertainty, economies of scale and sunk costs. In the absence of regulation we identify the market conditions under which a monopolist decides to invest early as well as the underlying overall welfare output. In a regulated environment, we consider a monopolist who faces no downstream (final good) competition but is subject to retail price regulation. We identify the welfare-maximizing regulated prices when the unregulated market outcome is set as the benchmark. We show that if the regulator can commit to ex post regulation – that is, regulated prices that are contingent to future demand realization – then regulated prices that allow the firm to recover its total costs of production are welfare-maximizing. Thus, under ex post price regulation there is no need to compensate the regulated firm for the option to delay that it foregoes when investing today. We argue, however, that regulators cannot make this type of commitment and, therefore, price regulation is often ex ante – that is, regulated prices are not contingent to future demand. We show that the optimal ex ante regulation, and the extent to which regulated prices need to incorporate an option to delay, depend on the nature of demand uncertainty.     

The Effect of Feed-in Tariffs on Renewable Electricity Generation: An Instrumental Variables Approach

While carbon taxes and other market-based instruments are widely regarded as optimal for climate mitigation, political constraints have prevented governments from using them. Instead, narrower instruments, including the feed-in tariff (FIT) for renewable electricity generation, have become popular. However, their causal effect on renewable electricity generation remains subject to uncertainty. We use instrumental variables to estimate the causal effect of FITs on renewable electricity generation in 26 industrialized countries, 1979–2005. We find that increasing the FIT by one U.S. cent (2000 constant prices) per kilowatt hour increases the percentage change in renewable electricity’s share of the total by 0.11 % points. All else constant, if a country implemented for a decade the sample mean FIT of three U.S. cents, the national share of renewable electricity would increase by 3.3 % points, which is more than the sample mean. In addition to demonstrating that the FIT is an effective way to increase renewable electricity generation, our approach lays the foundation for future studies of the causal effects of renewable energy policies.     

Uncertainty and climate treaties: Does ignorance pay?

Uncertainty and learning play an important role in the management of many environmental and resource problems and in particular in climate change. In stylized game-theoretic models of international environmental treaty formation, which capture the strategic interactions between nations, learning usually has a negative impact on the success of cooperation. We use a richer climate model that captures the large heterogeneity between different world regions and considers uncertainty about the benefits and costs from climate mitigation. By explicitly exploiting differences between regions and allowing transfers to mitigate free-rider incentives, we derive much more positive conclusions about the role of learning.     

Carbon offsets as an economic alternative to large-scale logging: a case study in Guyana

The objective of this study is to analyze the economic viability of carbon-offset projects that avoid logging in Guyana's forests. The results of this case study illustrate the cost effectiveness of alternative land-use options that reduce deforestation and associated greenhouse gas (GHG) emissions. This analysis demonstrates that using Guyana's rainforests for climate change mitigation can generate equivalent revenue to that of conventional large-scale logging without detrimental environmental impacts. At a 12% discount rate, the break-even price for carbon is estimated to be about US$ 0.20/tC. This estimate falls toward the low range of carbon prices for existing carbon offset projects that avoid deforestation.     

HOW TO DESIGN INFRASTRUCTURE CONTRACTS IN A WARMING WORLD: A CRITICAL APPRAISAL OF PUBLIC–PRIVATE PARTNERSHIPS*

We analyze how long‐term uncertainty, for example, regarding future climate conditions, affects the design of concession contracts and organizational forms in a principal–agent context, with dynamic moral hazard, limited liability, and irreversibility constraints. The prospect of future, uncertain productivity shocks on the returns on the firm's effort creates an option value of delaying efforts, a course that exacerbates agency costs. Contracts and organizational forms are drafted to control this cost of delegated flexibility. The possibility for the agent to delay investment in response to uncertainty and irreversibility also elicits preference for unbundling different stages of the project through short‐term contracts. Our analysis is relevant to infrastructure sectors that are sensitive to changing weather conditions and sheds a pessimistic light on the relevance of public–private partnerships in this context.     

Geographically explicit global modeling of land-use change, carbon sequestration, and biomass supply

This study aims to determine whether carbon sequestration policies could present a significant contribution to the global portfolio of climate change mitigation options. The objective is to model the effects of policies designed to induce landowners to change land use and management patterns with a view to sequester carbon or to reduce deforestation. The approach uses the spatially explicit Dynamic Integrated Model of Forestry and Alternative Land Use (DIMA) to quantify the economic potential of global forests. The model chooses which of the land-use processes (afforestation, reforestation, deforestation, or conservation and management options) would be applied in a specific location, based on land prices, cost of forest production and harvesting, site productivity, population density, and estimates of economic growth. The approach is relevant in that it (1) couples a revised and updated version of the Special Report on Emissions Scenarios with the dynamic development of climate policy implications through integration with the Model for Energy Supply Strategy Alternatives and their General Environmental Impact (MESSAGE); (2) is spatially explicit on a 0.5° grid; and (3) is constrained by guaranteeing food security and land for urban development. As outputs, DIMA produces 100-year forecasts of land-use change, carbon sequestration, impacts of carbon incentives (e.g., avoided deforestation), biomass for bioenergy, and climate policy impacts. The modeling results indicate that carbon sequestration policies could contribute to a significant part of the global portfolio of efficient climate mitigation policies, dependent upon carbon prices.     

Forest management for timber and carbon sequestration in the presence of climate change: The case of Pinus Sylvestris

Climatic changes will affect the dynamics of a forest ecosystem. Consequently, carbon sequestration costs can only be estimated correctly if changes in climatic conditions are considered. This article determines the changes in mitigation costs of an optimal forest management regime in the presence of climatic changes and varying prices, and takes account of substitution processes between timber production and carbon sequestration at the stand level. The study demonstrates that in the presence of climate change the sequestration costs per ton of carbon increase with higher amounts of carbon sequestered per hectare. This finding can be used to identify a threshold for the amount of sequestered carbon per hectare below which the costs of carbon sequestration are hardly influenced by climate change.     

Conscientious vs. ambivalent consumers: Do concerns about energy availability and climate change influence consumer behaviour?

Energy availability and climate change are interrelated concerns with economic components. They need to be addressed by policy makers and they require changes in energy consumption. This study examines whether concerns about energy availability and climate change influence consumer behaviour, policy perceptions, and beliefs about future energy consumption. This question is investigated by analysing data from the Eurobarometer 75.4, a comprehensive survey of citizens from all countries of the European Union that was conducted in June 2011 (n = 26,840). The regression results show that people concerned about climate change were significantly more likely to take action to mitigate climate change, and to be more favourably disposed towards energy policies and future changes in energy consumption, than people who were not concerned about climate change. On the other hand, people who were concerned about energy availability undertook fewer actions and neither supported energy policies nor believed in future changes in energy consumption. This surprising finding raises questions regarding the adequate communication of energy availability and policies to the public in the European Union.     

Willingness to Pay for Ancillary Benefits of Climate Change Mitigation

Assessing the Willingness to Pay (WTP) of the general public for climate change mitigation programmes enables governments to understand how much taxpayers are willing to support the implementation of such programs. This paper contributes to the literature on the WTP for climate change mitigation programmes by investigating, in addition to global benefits, the ancillary benefits of climate change mitigation. It does so by considering local and personal benefits arising from climate change policies. The Contingent Valuation Method is used to elicit the WTP for ancillary and global benefits of climate mitigation policies in the Basque Country, Spain. Results show that WTP estimates are 53–73% higher when ancillary benefits are considered.     

Implementing efficient conservation portfolio design

Modern tools for cost-effective conservation reserve site planning require the planner to have information about spatial distributions of conservation costs and benefits. Climate change creates unprecedented uncertainty about future land values and species habitat ranges, such that conservation scientists cannot map costs and benefits with certainty anymore. This paper contributes to the literature on the economics of conservation in the face of climate change uncertainty. It advances a new method for using modern portfolio theory to choose lands to protect that yield total conservation returns with less uncertainty. It explores the implications for portfolio recommendations of variation in the correlations between ecological and land-value responses to climate change. It also tests the robustness of the method to shortcuts that might be taken to simplify analysis, identifying problems that arise if conservation costs are ignored in portfolio analysis and demonstrating when portfolio recommendations are sensitive to how ecological benefits are quantified.     

Long-run equity risk and dynamic trading strategies: a simulation exercise for the Italian stock market

The paper develops a simulation approach capable of reproducing the high frequency characteristics of Italian stock market prices, without assuming any specific form for their stochastic process. The approach is then used to verify the capability of dynamic trading strategies to protect against downside risk in the long run. Because a fully funded capitalized retirement system will develop in Italy in the near future, dynamic trading strategies might become a widely used tool among Italian portfolio managers to hedge long-run equity risk, especially in view of the poor risk –return trade off that the stock market has historically provided. Both option replicating strategies and constant proportion strategies are simulated. The impact of transaction costs, non stationary return variances, alternative portfolio rebalancing schemes and various implementation constraints on the strategies cost are examined. For the option replicating strategies,ex posteffective costs turn out to be close toex antetheoretical expected cost. The crucial element in the strategy appears the decisions about the length of the option strategy and the rule to reset the floor at the end of it. Constant proportion strategies are cheaper and easier to implement, but their effectiveness depends too on the way in which the floor is adjusted as a function of the stock price movements. Broadly speaking, the simulations confirm that dynamic strategies are capable of delivering what they are supposed to achieve. All types of strategies are relatively straightforward and can be used with an acceptable margin of uncertainty.     

Prices versus quantities versus bankable quantities

Quantity-based regulation with banking allows regulated firms to shift obligations across time in response to periods of unexpectedly high or low marginal costs. Despite its wide prevalence in existing and proposed emission trading programs, banking has received limited attention in past welfare analyses of policy choice under uncertainty. We address this gap with a model of banking behavior that captures two key constraints: uncertainty about the future from the firm's perspective and a limit on negative bank values (e.g. borrowing). We show conditions where banking provisions reduce price volatility and lower expected costs compared to quantity policies without banking. For plausible parameter values related to U.S. climate change policy, we find that bankable quantities produce behavior quite similar to price policies for about two decades and, during this period, improve welfare by about a $1 billion per year over fixed quantities.     

Access pricing and investment: a real options approach

This paper examines a three-period model of an investment decision in a network industry characterized by demand uncertainty, economies of scale and sunk costs. In the absence of regulation we identify the market conditions under which a monopolist decides to invest early as well as the overall welfare generated by this decision. In a regulated environment, we consider a vertically integrated network provider that is required to provide access to downstream competitors and compare two distinct access pricing methodologies: the Efficient Component Pricing Rule (ECPR) and the Option to Delay Pricing Rule (ODPR). We identify the welfare-maximizing access prices using the unregulated market output as a benchmark and show that optimal access regulation depends on market conditions (that is, the nature of demand) with two possible outcomes: (i) access prices that provide a positive payoff to the incumbent, that is, provide a positive compensation to account for the option to delay; and (ii) access prices that yield a zero payoff to the incumbent. Moreover, unlike the earlier literature that argues in favor of an ECPR-type methodology to account for the interaction between irreversibility and demand uncertainty, we find that, except under very specific conditions, an access price that accounts for the option to delay value is welfare-superior to the ECPR.      

Distributional Preferences and the Incidence of Costs and Benefits in Climate Change Policy

We explore the relationship between willingness to pay (WTP) for climate change mitigation and distributional preferences, by which we mean individuals’ opinions about who should be responsible for climate change prevention and whether the share of climate change impacts borne by the poor is a cause for concern. We use 1,770 responses to an online stated preference survey. The domestic costs in our survey’s policy choice scenarios are expressed as a set of randomized shares across four different payment vehicles, and the international cost shares are randomized across four groups of countries. We also elicit respondents’ perceptions of the likely regressivity of climate change impacts under a policy of business-as-usual. WTP is higher when larger cost shares are borne by parties deemed to bear a greater responsibility for mitigation, and when respondents believe (and care) that the impacts of climate change may be borne disproportionately by the world’s poor. That WTP for an environmental policy depends on the distributional consequences of the policy is an unsettling result: efficiency assessments are typically assumed to be separate from equity considerations in most benefit-cost analyses.     

低碳农业发展核心目标:减缓和适应气候变化

减缓和适应是人类应对气候变化行动中两种相辅相成的措施。中国农业在应对气候变化中,减缓和适应同等重要:一方面,农业在减缓气候变化中具有独特的作用;另一方面,农业适应气候变化比减缓气候变化更为现实的迫切。积极发展低碳现代农业实现减排增汇,中国农业生态系统可以作为一种非常重要的固碳增汇措施,纳入全球CO2减排措施中去。中国低碳农业在减缓和适应气候变化中具有巨大潜力。     

Climate Response Uncertainty and the Benefits of Greenhouse Gas Emissions Reductions

Some recent research suggests that uncertainty about the response of the climate system to atmospheric greenhouse gas concentrations can have a disproportionately large influence on benefits estimates for climate change policies, potentially even dominating the effect of the discount rate. In this paper we conduct a series of numerical simulation experiments to investigate the quantitative significance of climate response uncertainty for economic assessments of climate change. First we characterize climate uncertainty by constructing two probability density functions—a Bayesian model-averaged and a Bayesian updated version—based on a combination of uncertainty ranges for climate sensitivity reported in the scientific literature. Next we estimate the willingness to pay of a representative agent for a range of emissions reduction policies using two simplified economic models. Our results illustrate the potential for large risk premiums in benefits estimates as suggested by the recent theoretical work on climate response uncertainty, and they show that the size and even the sign of the risk premium may depend crucially on how the posterior distribution describing the overall climate sensitivity uncertainty is constructed and on the specific shape of the damage function.