Edward A. Parson

Preparing for Climatic Change: The Water, Salmon, and Forests of the Pacific Northwest

The impacts of year-to-year and decade-to-decade climatic variations on some of the Pacific Northwests key natural resources can be quantified to estimate sensitivity to regional climatic changes expected as part of anthropogenic global climatic change. Warmer, drier years, often associated with El Niño events and/or the warm phase of the Pacific Decadal Oscillation, tend to be associated with below-average snowpack, streamflow, and flood risk, below-average salmon survival, below-average forest growth, and above-average risk of forest fire. During the 20th century, the region experienced a warming of 0.8 °C. Using output from eight climate models, we project a further warming of 0.5–2.5 °C (central estimate 1.5 °C) by the 2020s, 1.5–3.2°C (2.3 °C) by the 2040s, and an increase in precipitation except in summer. The foremost impact of a warming climate will be the reduction of regional snowpack, which presently supplies water for ecosystems and human uses during the dry summers. Our understanding of past climate also illustrates the responses of human management systems to climatic stresses, and suggests that a warming of the rate projected would pose significant challenges to the management of natural resources. Resource managers and planners currently have few plans for adapting to or mitigating the ecological and economic effects of climatic change.

Research on global sun block needed now

Geoengineering studies of solar-radiation management should begin urgently, argue David W. Keith, Edward Parson and M. Granger Morgan — before a rogue state decides to act alone.

Integrated assessment and environmental policy making In pursuit of usefulness

Current integrated assessment projects primarily seek end to end integration through formal models at a national to global scale, and show three significant representational weaknesses: determinants of decadal-scale emissions trends; valuing impacts and adaptive response; and the formation and effects of policies. Meeting the needs of policy audiences may require other forms of integration; may require integration by formal modeling or by other means; and may require representing decisions of other actors through political and negotiating processes. While rational global environmental policy making requires integrated assessment, current practice admits no single vision of how to do it, so understanding will be best advanced by a diverse collection of projects pursuing distinct methods and approaches. Further practice may yield some consensus on best practice, possibly including generic assessment skills generalizable across issues.

UNDERSTANDING CLIMATIC IMPACTS, VULNERABILITIES, AND ADAPTATION IN THE UNITED STATES: BUILDING A CAPACITY FOR ASSESSMENT

Based on the experience of the U.S. National Assessment, we propose a program of research and analysis to advance capability for assessment of climate impacts, vulnerabilities, and adaptation options. We identify specific priorities for scientific research on the responses of ecological and socioeconomic systems to climate and other stresses; for improvement in the climatic inputs to impact assessments; and for further development of assessment methods to improve their practical utility to decision-makers. Finally, we propose a new institutional model for assessment, based principally on regional efforts that integrate observations, research, data, applications, and assessment on climate and linked environmental-change issues. The proposed program will require effective collaboration between scientists, resource managers, and other stakeholders, all of whose expertise is needed to define and prioritize key regional issues, characterize relevant uncertainties, and assess potential responses. While both scientifically and organizationally challenging, such an integrated program holds the best promise of advancing our capacity to manage resources and the economy adaptively under a changing climate.

End the Deadlock on Governance of Geoengineering Research

Can scientific self-regulation control small-scale research, or is governmental regulation needed? Proposals for research on geoengineering methods to offset greenhouse-gas–driven climate change have attracted controversy (1–6). Multiple methods have been proposed (7), but attention and controversy have centered on methods to reduce incoming sunlight—for example, spreading reflective aerosols in the stratosphere or spraying condensation nuclei to increase low ocean clouds (1, 2). Such high-leverage interventions offer the dual prospect of large benefits and harms. They may reduce climate-change risks faster than any other response. Yet they may also cause environmental harm or worsen policy failures—for example, undermining emissions cuts or triggering international conflict. Research is needed to develop capabilities and assess effectiveness and risks (field research as well as model and laboratory studies), but geoengineering requires competent, prudent, and legitimate governance (1, 2, 8). We propose specific steps to advance progress on research governance.

Useful Global-Change Scenarios: Current Issues and Challenges

Scenarios are increasingly used to inform global-change debates, but their connection to decisions has been weak and indirect. This reflects the greater number and variety of potential users and scenario needs, relative to other decision domains where scenario use is more established. Global-change scenario needs include common elements, e.g., model-generated projections of emissions and climate change, needed by many users but in different ways and with different assumptions. For these common elements, the limited ability to engage diverse global-change users in scenario development requires extreme transparency in communicating underlying reasoning and assumptions, including probability judgments. Other scenario needs are specific to users, requiring a decentralized network of scenario and assessment organizations to disseminate and interpret common elements and add elements requiring local context or expertise. Such an approach will make global-change scenarios more useful for decisions, but not less controversial. Despite predictable attacks, scenario-based reasoning is necessary for responsible global-change decisions because decision-relevant uncertainties cannot be specified scientifically. The purpose of scenarios is not to avoid speculation, but to make the required speculation more disciplined, more anchored in relevant scientific knowledge when available, and more transparent.

Environmental health implications of global climate change

This paper reviews the background that has led to the now almost-universally held opinion in the scientific community that global climate change is occurring and is inescapably linked with anthropogenic activity. The potential implications to human health are considerable and very diverse. These include, for example, the increased direct impacts of heat and of rises in sea level, exacerbated air and water-borne harmful agents, and--associated with all the preceding--the emergence of environmental refugees. Vector-borne diseases, in particular those associated with blood-sucking arthropods such as mosquitoes, may be significantly impacted, including redistribution of some of those diseases to areas not previously affected. Responses to possible impending environmental and public health crises must involve political and socio-economic considerations, adding even greater complexity to what is already a difficult challenge. In some areas, adjustments to national and international public health practices and policies may be effective, at least in the short and medium terms. But in others, more drastic measures will be required. Environmental monitoring, in its widest sense, will play a significant role in the future management of the problem.

Informing global environmental policy‐making: A plea for new methods of assessment and synthesis

Practice and research in assessment of global environmental change are dominated by two conventional assessment methods, formal models and expert panels. Models construct a representation of biophysical and socio‐economic components of a policy issue, to project future trends or consequences of interventions. Panels articulate consensus views of policy‐relevant knowledge through deliberations among selected experts. These methods make valuable contributions, but are weak in addressing certain kinds of knowledge needs that are typical of global‐change issues. To address these needs, a set of novel assessment methods is proposed that combine elements of representation and deliberation. These methods, of which policy exercises, simulation‐gaming, and scenario exercises are examples, involve human participants in structured relevant decision and task settings. Relative to models and panels, these methods can more readily incorporate diverse perspectives, can integrate across broader collections of knowledge domains, and can both encourage creative insights and innovations, and provide tests of their relevance and practicality. Risks of bias, and of over‐confident generalization from unique experiences, are effectively mitigated by critical debriefings, and appear no more severe than corresponding risks in conventional assessment methods, or in policy‐makers’ generalizations from historical experience. While serious development and implementation challenges remain, early experience suggests that these methods can offer useful ideas and insights for policy‐making that are not available through other means.

International Governance of Climate Engineering

Continued failure to limit emissions of carbon dioxide and other greenhouse gases that are causing global climate change has brought increased attention to climate engineering (CE) technologies, which actively modify the global environment to counteract heating and climate disruptions caused by elevated greenhouse gases. Some proposed forms of CE, particularly spraying reflective particles in the upper atmosphere to reduce incoming sunlight, can cool the average temperature of the Earth rapidly and cheaply, thereby substantially reducing climate-related risks. Yet CE interventions provide only imperfect corrections for the climatic and other environmental effects of elevated greenhouse gases, and carry their own environmental risks. Moreover, they may also increase other risks, by weakening political support for essential emissions reductions or providing new triggers for international conflict. These technologies thus require international governance, but also pose novel and severe challenges to current international laws and institutions. Effective governance of CE will require a capacity to make decisions regarding the conditions, if any, under which specific interventions are authorized, plus realtime operational oversight of any interventions that are conducted. Decision processes must be effectively linked with scientific research and assessment, and with institutions to manage and respond to threats of CE-related conflict. We advance preliminary suggestions to address two priority areas for early investigation: how international cooperation on early CE research can help develop shared norms that can grow robust enough to support future decision needs; and how early research and development on CE can be made to complement and encourage, rather than undermine, parallel efforts to reduce climate risks by cutting emissions.

Climate Engineering in Global Climate Governance: Implications for Participation and Linkage

The prospect of climate engineering (CE) — modification of the global environment to partly offset climate change and impacts from elevated atmospheric greenhouse gases — poses major, disruptive challenges to international policy and governance. If full global cooperation to manage climate change is not initially achievable, adding CE to the agenda has major effects on the challenges and risks associated with alternative configurations of participation, e.g., variants of partial cooperation, unilateral action, and exclusion. Although risks of unilateral CE by small states or non-state actors have been over-stated, a dozen-odd powerful states may be able to pursue CE unilaterally, risking international destabilization and conflict. These risks are not limited to future CE deployment, but may also be triggered by unilateral R&D, secrecy about intentions and capabilities, or assertion of legal rights of unilateral action. They may be reduced by early cooperative steps such as international R&D collaboration and open sharing of information. CE presents novel opportunities for explicit bargaining linkages within a complete climate response. Four CE-mitigation linkage scenarios suggest how CE may enhance mitigation incentives, not weaken them as commonly assumed. Such synergy appears challenging if CE is treated only as a contingent response to a future climate crisis, but may be more achievable if CE is used earlier and at lower intensity, either to reduce peak near-term climate disruption in parallel with a program of deep emission cuts or to target regional climate processes linked to acute global risks.