Uncertainty In Climate Science Research Articles

The Social Cost of Carbon When We Wish for Full-Path Robustness

We compute the social cost of carbon (SCC) when decision makers want robust estimates in the face of deep (or “Knightian”) uncertainty. We introduce the notion of full-path accumulated robust preferences from stochastic control theory to an integrated assessment model. Robust preferences are appropriate for analyzing climate-related problems because, given the large uncertainty in climate science, they enable decision makers to attain solutions that are robust to a wide range of climate change scenarios. We solve the resulting model, which includes uncertainty about climate change and the ensuing economic damage and show the existence of optimal solutions and time-consistent optimal deterministic Markov policies. Additionally, we also prove that the standard Hansen–Sargent recursive utility provides an upper bound of this full-path utility. In our baseline model specification, we find that the year 2020’s optimal SCC is US$162 per tCO2with an average annual growth rate of 2.5%, setting the world on a 1.37°C path, which requires full decarbonization by 2068. We introduce the notion of the SCC robustness premium, which we define as the additional SCC price tag for robustness. For a plausible range of preference parameters, the SCC robustness premium in 2020 is between US$1.41 and US$25.89 per tCO2with US$2.20 per tCO2in our baseline calibration. Over time, this premium grows significantly. The forecasts of our model facilitate managerial decision making during the world’s transition from a carbon- and emission-intensive economy to a regenerative economy. The high estimates for the SCC predict drastic rises in emission costs for high-emission industries.This paper was accepted by Elke Weber, Special Section of Management Science on Business and Climate Change.Funding: Y. Zhao and T. S. Lontzek acknowledge funding by the German Ministry of Research and Education (BMBF), Project CDR: “DAC-Tales”, under [Grant 01LS2196A].Supplemental Material: The data files are available at https://doi.org/10.1287/mnsc.2023.4736 .

A decline in the carbon fertilization effect

Climate Change One source of uncertainty in climate science is how the carbon fertilization effect (CFE) will contribute to mitigation of anthropogenic climate change. Wang et al. explored the temporal dynamics of CFE on vegetation photosynthesis at the global scale. There has been a decline over recent decades in the contribution of CFE to vegetation photosynthesis, perhaps owing to the limiting effects of plant nutrients such as nitrogen and phosphorus. This declining trend has not been adequately accounted for in carbon cycle models. CFE thus has limitations for long-term mitigation of climate change, and future warming might currently be underestimated. Science , this issue p. [1295][1] [1]: /lookup/doi/10.1126/science.abb7772

Recent global decline of CO2 fertilization effects on vegetation photosynthesis.

The enhanced vegetation productivity driven by increased concentrations of carbon dioxide (CO2) [i.e., the CO2 fertilization effect (CFE)] sustains an important negative feedback on climate warming, but the temporal dynamics of CFE remain unclear. Using multiple long-term satellite- and ground-based datasets, we showed that global CFE has declined across most terrestrial regions of the globe from 1982 to 2015, correlating well with changing nutrient concentrations and availability of soil water. Current carbon cycle models also demonstrate a declining CFE trend, albeit one substantially weaker than that from the global observations. This declining trend in the forcing of terrestrial carbon sinks by increasing amounts of atmospheric CO2 implies a weakening negative feedback on the climatic system and increased societal dependence on future strategies to mitigate climate warming.

An Economist’s Guide to Climate Change Science

This article provides a brief introduction to the physical science of climate change, aimed towards economists. We begin by describing the physics that controls global climate, how scientists measure and model the climate system, and the magnitude of human-caused emissions of carbon dioxide. We then summarize many of the climatic changes of interest to economists that have been documented and that are projected in the future. We conclude by highlighting some key areas in which economists are in a unique position to help climate science advance. An important message from this final section, which we believe is deeply underappreciated among economists, is that all climate change forecasts rely heavily and directly on economic forecasts for the world. On timescales of a half-century or longer, the largest source of uncertainty in climate science is not physics, but economics.

Initial-Condition Dependence and Initial-Condition Uncertainty in Climate Science

Abstract This article examines initial-condition dependence and initial-condition uncertainty for climate projections and predictions. The first contribution is to provide a clear conceptual characterization of predictions and projections. Concerning initial-condition dependence, projections are often described as experiments that do not depend on initial conditions. Although prominent, this claim has not been scrutinized much and can be interpreted differently. If interpreted as the claim that projections are not based on estimates of the actual initial conditions of the world or that what makes projections true are conditions in the world, this claim is true. However, it can also be interpreted as the claim that simulations used to obtain projections are independent of initial-condition ensembles. This article argues that evidence does not support this claim. Concerning initial-condition uncertainty, three kinds of initial-condition uncertainty are identified (two have received little attention from philosophers so far). The first (the one usually discussed) is the uncertainty associated with the spread of the ensemble simulations. The second arises because the theoretical initial ensemble cannot be used in calculations and has to be approximated by finitely many initial states. The third uncertainty arises because it is unclear how long the model should be run to obtain potential initial conditions at pre-industrial times. Overall, the discussion shows that initial-condition dependence and uncertainty in climate science are more complex and important issues than usually acknowledged. 1Introduction2Projections and Predictions 2.1Predictions2.2Projections3Initial-Condition Dependence 3.1Projections 3.1.1Dynamical conditions justifying independence of initial conditions?3.1.2What projections can and cannot provide3.2Predictions4Initial-Condition Uncertainty 4.1Projections4.2Predictions5ConclusionAppendix

Party Elites or Manufactured Doubt? The Informational Context of Climate Change Polarization

Americans polarized on climate change despite decreasing uncertainty in climate science. Explanations focused on organized climate skeptics and ideologically driven motivated reasoning are likely i...

Improving the communication of uncertainty in climate science and intelligence analysis

Public policymakers routinely receive and communicate information characterized by uncertainty. Decisions based on such information can have important consequences, so it is imperative that uncertainties are communicated effectively. Many organizations have developed dictionaries, or lexicons, that contain specific language (e.g., very likely, almost certain) to express uncertainty. But these lexicons vary greatly and only a few have been empirically tested. We have developed evidence-based methods to standardize the language of uncertainty so that it has clear meaning understood by all parties in a given communication. We tested these methods in two policy-relevant domains: climate science and intelligence analysis. In both, evidence-based lexicons were better understood than those now used by the Intergovernmental Panel on Climate Change, the U.S. National Intelligence Council, and the U.K. Defence Intelligence. A well-established behavioral science method for eliciting the terms’ full meaning was especially effective for deriving such lexicons.

Communicating climate change: conduits, content, and consensus

Climate change has been the subject of increasing efforts by scientists to understand its causes and implications; it has been of growing interest to policymakers, international bodies, and a variety of nongovernment organizations; and it has attracted varied amounts of attention from traditional and, increasingly, online media. These developments have been aligned with shifts in the nature of climate change communication, with changes in how researchers study it and how a variety of actors try to influence it. This article situates the theory and practice of climate change communication within developments that have taken place since we first reviewed the field in 2009. These include the rise of new social media conduits for communication, research, and practice aimed at fine tuning communication content, and the rise to prominence of scientific consensus as part of that content. We focus in particular on continuing tensions between a focus on the part of communicators to inform the public and more dialogic strategies of public engagement. We also consider the tension between efforts to promote consensus and certainty in climate science and approaches that attempt to engage with uncertainty more fully. We explore the lessons to be learnt from climate communication since 2009, highlighting how the field remains haunted by the deficit model of science communication. Finally, we point to more fruitful future directions for climate change communication, including more participatory models that acknowledge, rather than ignore, residual uncertainties in climate science in order to stimulate debate and deliberation. WIREs Clim Change 2015, 6:613–626. doi: 10.1002/wcc.366This article is categorized under: Perceptions, Behavior, and Communication of Climate Change > Communication

Improving the communication of uncertainty in climate science and intelligence analysis

Public policymakers routinely receive and communicate information characterized by uncertainty. Decisions based on such information can have important consequences, so it is imperative that uncertainties are communicated effectively. Many organizations have developed dictionaries, or lexicons , that contain specific language (e.g., very likely , almost certain ) to express uncertainty. But these lexicons vary greatly and only a few have been empirically tested. We have developed evidence-based methods to standardize the language of uncertainty so that it has clear meaning understood by all parties in a given communication. We tested these methods in two policy-relevant domains: climate science and intelligence analysis. In both, evidence-based lexicons were better understood than those now used by the Intergovernmental Panel on Climate Change, the U.S. National Intelligence Council, and the U.K. Defence Intelligence. A well-established behavioral science method for eliciting the terms’ full meaning was especially effective for deriving such lexicons.

Global Warming Advocacy Science: A Cross Examination

Legal scholarship has come to accept as true the various pronouncements of the Intergovernmental Panel on Climate Change (IPCC) and other scientists who have been active in the movement for greenhouse gas (ghg) emission reductions to combat global warming. The only criticism that legal scholars have had of the story told by this group of activist scientists - what may be called the climate establishment - is that it is too conservative in not paying enough attention to possible catastrophic harm from potentially very high temperature increases. This paper departs from such faith in the climate establishment by comparing the picture of climate science presented by the Intergovernmental Panel on Climate Change (IPCC) and other global warming scientist advocates with the peer-edited scientific literature on climate change. A review of the peer-edited literature reveals a systematic tendency of the climate establishment to engage in a variety of stylized rhetorical techniques that seem to oversell what is actually known about climate change while concealing fundamental uncertainties and open questions regarding many of the key processes involved in climate change. Fundamental open questions include not only the size but the direction of feedback effects that are responsible for the bulk of the temperature increase predicted to result from atmospheric greenhouse gas increases: while climate models all presume that such feedback effects are on balance strongly positive, more and more peer-edited scientific papers seem to suggest that feedback effects may be small or even negative. The cross-examination conducted in this paper reveals many additional areas where the peer-edited literature seems to conflict with the picture painted by establishment climate science, ranging from the magnitude of 20th century surface temperature increases and their relation to past temperatures; the possibility that inherent variability in the earth’s non-linear climate system, and not increases in CO2, may explain observed late 20th century warming; the ability of climate models to actually explain past temperatures; and, finally, substantial doubt about the methodological validity of models used to make highly publicized predictions of global warming impacts such as species loss. Insofar as establishment climate science has glossed over and minimized such fundamental questions and uncertainties in climate science, it has created widespread misimpressions that have serious consequences for optimal policy design. Such misimpressions uniformly tend to support the case for rapid and costly decarbonization of the American economy, yet they characterize the work of even the most rigorous legal scholars. A more balanced and nuanced view of the existing state of climate science supports much more gradual and easily reversible policies regarding greenhouse gas emission reduction, and also urges a redirection in public funding of climate science away from the continued subsidization of refinements of computer models and toward increased spending on the development of standardized observational datasets against which existing climate models can be tested.

Quantifying uncertainty in climate science

Quantifying uncertainty in climate science

Real Options as a Decision-making Tool in Climate Finance Evaluated with a Case Study on CCS

Climate action is a challenging task and uncertainties in climate science make decision making extremely difficult. In this paper we evaluate the role that Real Options can play in helping decision making towards climate action. It also looks into whether evaluation via Real Options — keeping uncertainties in mind — will be a sensible choice from a broader macroeconomic viewpoint. While no single measure may alone be sufficient for climate change mitigation, Carbon Capture and Sequestration/Storage (CCS), along with energy efficiency improvements, renewable energy, enhancement of biological sinks, and other measures, may be able to achieve the emissions reductions needed to achieve climate stabilization. In addition, there will be important decisions in climate adaptation areas too, further adding to the complexities of decision making for climate action. In this paper, a normative case study is incorporated to determine the cost of CCS action in India. While arriving at the costs, a provision for the financial risk of storage has also been added. Given the costs, Real Options analysis is undertaken to arrive at a decision. The Real Options valuation is done using the Black-Scholes method. Ultimately, the Real Options framework is scrutinized from a broader macroeconomic perspective to understand its suitability for a more dynamic global economy as well as the effects of large climate funds on the framework, including how important a decision-making framework like Real Options is for a sustainable world.

Two Faces of Uncertainty: Climate Science and Water Utility Planning Methods

Water utilities are increasingly incorporating climate change in their planning activities. A water manager embarking on such a study is often confronted with a large range of climate model projections and the need to incorporate this new source of uncertain information into existing management and operations models. This article discusses these two faces of uncertainty and argues that an increased awareness of both the sources of this uncertainty in climate science and the means to plan for it can help utilities meet this challenge. More specifically, this article investigates the prospects for climate science to provide useful projections, discusses the strategies and challenges faced in translating those projections into effects on water utilities, and presents several decision-support planning methods that are being used or considered for use in several water utilities in the United States. Traditional water utility planning methods are based on an assumption of stationarity—that future hydrology will not significantly deviate from past hydrology. The current scientific understanding of climate change fundamentally challenges this stationarity assumption (Milly et al. 2008). In recognition of the limitations of stationarity, many water utilities are broadening their understanding of climate change and investigating decision-support planning methods to cope with conditions of pervasive climatic uncertainty. Uncertainty in projections of climate change can act as a barrier to the effective use of climate change information. Projections of future climate rely heavily on climate models (also known as general circulation models, or GCMs). On local and regional scales, and for variables such as precipitation and streamflow, the uncertainty in model projections is even greater than for global averages (Hawkins and Sutton 2011), and models may not even agree on the direction of change. Under such conditions, water management and planning must incorporate the new uncertainty of changing climatic conditions, a task for which traditional planning methods are poorly suited. Awater utility’s ability to effectively use this new uncertain scientific information may require adjustments to their management and planning processes, or even the adoption of new approaches. In an important sense, the water resources management community has taken a leadership role in understanding and incorporating climate change into their management, operations, and planning. Much of this effort has occurred at a utility scale, i.e., individual utilities working internally or with an academic and/or consultant partner to investigate the significance of climate change for the resources they manage [East Bay Municipal Utility District (EBMUD) 2009; New York City Department of Environmental Protection (NYCDEP) 2008; Palmer 2007; Palmer and Hahn 2002]. Water resources trade organizations such as the Water Research Foundation (WaterRF), the WateReuse Foundation, and the Water Environment Research Foundation have funded a number of studies investigating the effects of climate change on their member utilities (Miller and Yates 2006; Stratus Consulting and MWH Global 2009; WRF 2010). More recently, some of the largest metropolitan water agencies in the United States formed the Water Utility Climate Alliance (WUCA) to pursue their common objective of understanding and incorporating climate change information into their management, operations, and planning. Water utilities routinely examine the vulnerability of their systems to uncertain factors such as massive supply disruptions, infrastructure failure, potential regulatory requirements, technological changes, and even terrorist attacks. Although climate change may be thought of as simply one more uncertain variable that must be taken into account in water resources management, successfully incorporating this new uncertain information has not proven to be easy, in part because of the assumption of stationary hydrology in existing planning methods. In this article we explore the state of knowledge and practice in several large water utilities in the United States by synthesizing, updating, and greatly condensing the information that the authors developed for four recent studies by the WUCA and the U.S. Environmental Protection Agency (EPA). The first WUCA white paper (Barsugli et al. 2009) focuses on the state of climate modeling, on understanding water utility informational needs and desires, and on assessing which investments in climate science or modeling may yield usability improvements from the perspective of water utilities. The second WUCA white paper (Means et al. 2010) describes five decision-support planning methods that consider multiple future conditions and outcomes to incorporate greater uncertainties into the water planning process.

Climate Science and the Uncertainty Monster

How to understand and reason about uncertainty in climate science is a topic that is receiving increasing attention in both the scientific and philosophical literature. This paper provides a perspective on exploring ways to understand, assess, and reason about uncertainty in climate science, including application to the Intergovernmental Panel on Climate Change (IPCC) assessment reports. Uncertainty associated with climate science and the science–policy interface presents unique challenges owing to the complexity of the climate system itself, the potential for adverse socioeconomic impacts of climate change, and the politicization of proposed policies to reduce societal vulnerability to climate change. The challenges to handling uncertainty at the science– policy interface are framed using the “monster” metaphor, whereby attempts to tame the monster are described. An uncertainty lexicon is provided that describes the natures and levels of uncertainty and ways of representing and reasoning about uncertaint...

Laboratory simulations show diabatic heating drives cumulus-cloud evolution and entrainment

Clouds are the largest source of uncertainty in climate science, and remain a weak link in modeling tropical circulation. A major challenge is to establish connections between particulate microphysics and macroscale turbulent dynamics in cumulus clouds. Here we address the issue from the latter standpoint. First we show how to create bench-scale flows that reproduce a variety of cumulus-cloud forms (including two genera and three species), and track complete cloud life cycles--e.g., from a "cauliflower" congestus to a dissipating fractus. The flow model used is a transient plume with volumetric diabatic heating scaled dynamically to simulate latent-heat release from phase changes in clouds. Laser-based diagnostics of steady plumes reveal Riehl-Malkus type protected cores. They also show that, unlike the constancy implied by early self-similar plume models, the diabatic heating raises the Taylor entrainment coefficient just above cloud base, depressing it at higher levels. This behavior is consistent with cloud-dilution rates found in recent numerical simulations of steady deep convection, and with aircraft-based observations of homogeneous mixing in clouds. In-cloud diabatic heating thus emerges as the key driver in cloud development, and could well provide a major link between microphysics and cloud-scale dynamics.

Reducing problems through reduced complexity? Considering the benefits and limits of economic perspectives on climate change

Economic perspectives on climate change loom large since the publication of the commonly called Stern Report, Economics of Climate Change. A great number of studies subsequently employ similar approaches. Considering the huge uncertainties in climate science, however, these calculations raise a number of questions: How can costs and benefits of emissions reductions be assessed and compared for time frames up to 200 years? What is the basic rationality these studies rely on? And how can the high relevance of this perspective be explained? To answer these questions, this paper examines three corresponding studies and highlights their role for current political debates. The reduction of complexity in these studies allows for a certain economic perspective on climate change. Drawing on discourse theory, this perspective is located within a wider economic rationality within climate politics that suggests finance and investment as response strategies.

Media and scientific communication: a case of climate change

Abstract This paper explores how media representational practices shape and affect current international science and policy or practice communications, through a focus on climate change. Many complex factors contribute to these interactions. The norms and pressures that guide journalistic decision-making and shape mass-media coverage of anthropogenic climate science critically shape current discourses at the highly politicized climate science–policy interface. This paper investigates the multifarious journalistic, political, cultural and economic norms that dynamically influence media coverage of climate science. It explores the case-study of climate change to also work through factors shaping the translation of uncertainty in climate science. This project demonstrates that mass-media coverage of climate change is not simply a random amalgam of articles and segments; rather, it is a social relationship between scientists, policy actors and the public that is mediated by such news packages. Moreover, this research shows how mass media play a significant role in shaping the construction and maintenance of discourse on climate change at the interface of science and policy.

Climate Change Policy: A Survey200310Climate Change Policy: A Survey. Island Press, 2002. , ISBN: 1‐55963‐881‐8 US$23.60

Questions surrounding the issue of climate change are evolving from it happening? to what can be done about it?. The primary obstacles to addressing it at this point are not scientific but political and economic; nonetheless a quick resolution is unlikely. Ignorance and confusion surrounding the issue - including lack of understanding of climate science, its implications for the environment and society, and the range of policy options available - contributes to the political morass over dealing with climate change in which we find ourselves. This text addresses that situation by bringing together a wide range of writings that examine the many dimensions of the topics most important in understanding climate change and policies to consider it. The chapters consider: climate science in historical perspective; analysis of uncertainties in climate science and policy; the economics of climate policy; north-south and intergenerational equity issues; the role of business and industry in climate solutions; and policy mechanisms including joint implementation, emissions trading, and the so-called clean development mechanism.