Potential for large-scale CO2 removal via enhanced rock weathering with croplands.

Enhanced silicate rock weathering (ERW), deployable with croplands, has potential use for atmospheric carbon dioxide (CO2) removal (CDR), which is now necessary to mitigate anthropogenic climate change1. ERW also has possible co-benefits for improved food and soil security, and reduced ocean acidification2-4. Here we use an integrated performance modelling approach to make an initial techno-economic assessment for 2050, quantifying how CDR potential and costs vary among nations in relation to business-as-usual energy policies and policies consistent with limiting future warming to 2 degrees Celsius5. China, India, the USA and Brazil have great potential to help achieve average global CDR goals of 0.5 to 2 gigatonnes of carbon dioxide (CO2) per year with extraction costs of approximately US$80-180 per tonne of CO2. These goals and costs are robust, regardless of future energy policies. Deployment within existing croplands offers opportunities to align agriculture and climate policy. However, success will depend upon overcoming political and social inertia to develop regulatory and incentive frameworks. We discuss the challenges and opportunities of ERW deployment, including the potential for excess industrial silicate materials (basalt mine overburden, concrete, and iron and steel slag) to obviate the need for new mining, as well as uncertainties in soil weathering rates and land-ocean transfer of weathered products.

Perceptions of enhanced weathering as a biological negative emissions option.

This paper addresses the social acceptability of enhanced weathering, a technology that would involve spreading silicate particles over terrestrial surfaces in order to boost the biological processes that currently sequester CO2 as part of the earth's natural carbon cycle. We present the first exploration of British attitudes towards enhanced weathering, using an online survey (n = 935) of a representative quota sample of the public. Baseline awareness of weathering was extremely low. Many respondents remained undecided or neutral about risks, although more people support than oppose weathering. Factors predicting support for weathering and its research included feelings about the technology and trust in scientists. Over half of the sample agrees that scientists should be able to conduct research into effectiveness and risks, but with conditions also placed upon how research is conducted, including the need for scientific independence, small-scale trials, strict monitoring, risk minimization and transparency of results. Public engagement is needed to explore in more detail why particular individuals feel either positive or negative about weathering, and why they believe particular conditions should be applied to research, as part of wider responsible research and innovation processes for biological and other types of negative emissions technologies.

The perceived health risks of indoor radon gas and overhead powerlines: a comparative multilevel approach.

Radon and overhead powerlines are two radiation risk cases that have raised varying levels of concern among the general public and experts. Despite both involving radiation-a typically feared and unseen health hazard-individuals' perceptions of the two risk cases may invoke rather different factors. We examined individual and geographic-contextual factors influencing public perceptions of the health risks of indoor radon gas and overhead powerlines in a comparative research design, utilizing a postal questionnaire with 1,528 members of the general public (response rate 28%) and multilevel modeling techniques. This study found that beliefs about the two risk cases mainly differed according to the level of "exposure"-defined here in terms of spatial proximity. We argue that there are two alternative explanations for this pattern of findings: that risk perception itself varies directly with proximity, or that risk is more salient to concerned people in the exposed areas. We also found that while people living in high radon areas are more concerned about the risks of indoor radon gas, they find these risks more acceptable and have more trust in authorities. These results might reflect the positive effects of successive radon campaigns in high radon areas, which may have raised awareness and concern, and at the same time may have helped to increase trust by showing that the government takes the health risks of indoor radon gas seriously, suggesting that genuine risk communication initiatives may have positive impacts on trust in risk management institutions.

Exploring the structure of attitudes toward genetically modified food.

Although it is often thought that the British public is opposed to genetically modified (GM) food, recent qualitative work suggests that most people are ambivalent about GM food and crops. In this article we explore the structure of attitudes in order to examine whether attitudinal ambivalence can be captured by more quantitative methods. Based on the finding that the perceived risks and benefits of GM food can be treated as independent dimensions, we propose a four-way typology of attitudes, consisting of a positive, negative, indifferent, and ambivalent group. This study showed that the differences between the four groups could best be described by three main dimensions: (1) a general evaluative dimension, (2) an involvement dimension, and (3) an attitudinal certainty dimension. While these different attitudinal dimensions have generally been studied in isolation, we argue that they should be studied collectively.

Using surveys in public participation processes for risk decision making: the case of the 2003 British GM Nation? Public debate.

This article takes as its case study the "GM Nation?" public debate, a major participation process on the commercialization of agricultural biotechnology, which occurred in Britain during the summer of 2003. We investigate possible self-selection biases in over 36,000 open questionnaire responses on the risks and benefits of genetically modified crops and food obtained during GM Nation? A comparison sample of equivalent responses from a statistically representative sample (n = 1,363) of the British general public obtained shortly after the conclusion of the debate is reported. This comparison shows that the GM Nation? open responses were indeed not fully representative of British "public opinion" regarding agricultural biotechnology. Rather, such opinion is not a unitary whole, but fragmented, with considerable ambivalence coexisting alongside outright opposition to GM agriculture. The methodological implications for multistage participation processes are discussed: in particular, the need to anticipate outcomes of complex design decisions, and to include representative public surveys as standard where measures of broader public attitudes to risk are an important objective.

Trust in risk regulation: cause or consequence of the acceptability of GM food?

Although there is ample empirical evidence that trust in risk regulation is strongly related to the perception and acceptability of risk, it is less clear what the direction of this relationship is. This article explores the nature of the relationship, using three separate data sets on perceptions of genetically modified (GM) food among the British public. The article has two discrete but closely interrelated objectives. First, it compares two models of trust. More specifically, it investigates whether trust is the cause (causal chain account) or the consequence (associationist view) of the acceptability of GM food. Second, this study explores whether the affect heuristic can be applied to a wider number of risk-relevant concepts than just perceived risk and benefit. The results suggest that, rather than a determinant, trust is an expression or indicator of the acceptability of GM food. In addition, and as predicted, "affect" accounts for a large portion of the variance between perceived risk, perceived benefit, trust in risk regulation, and acceptability. Overall, the results support the associationist view that specific risk judgments are driven by more general evaluative judgments The implications of these results for risk communication and policy are discussed.

Dangerous climate change: the role for risk research.

The notion of "dangerous climate change" constitutes an important development of the 1992 United Nations Framework Convention on Climate Change. It persists, however, as an ambiguous expression, sustained by multiple definitions of danger. It also implicitly contains the question of how to respond to the complex and multi-disciplinary risk issues that climate change poses. The invaluable role of the climate science community, which relies on risk assessments to characterize system uncertainties and to identify limits beyond which changes may become dangerous, is acknowledged. But this alone will not suffice to develop long-term policy. Decisions need to include other considerations, such as value judgments about potential risks, and societal and individual perceptions of "danger," which are often contested. This article explores links and cross-overs between the climate science and risk communication and perception approaches to defining danger. Drawing upon nine articles in this Special Issue of Risk Analysis, we examine a set of themes: limits of current scientific understanding; differentiated public perceptions of danger from climate change; social and cultural processes amplifying and attenuating perceptions of, and responses to, climate change; risk communication design; and new approaches to climate change decision making. The article reflects upon some of the difficulties inherent in responding to the issue in a coherent, interdisciplinary fashion, concluding nevertheless that action should be taken, while acknowledging the context-specificity of "danger." The need for new policy tools is emphasised, while research on nested solutions should be aimed at overcoming the disjunctures apparent in interpretations of climate change risks.

Trust, the asymmetry principle, and the role of prior beliefs.

Within the risk literature there is an ongoing debate on whether trust is vulnerable or enduring. Previous research on nuclear energy by Slovic in 1993 has shown that negative events have much greater impact on self-reported trust than do positive events. Slovic attributes this to the asymmetry principle: specifically, that trust is much easier to destroy than to create. In a questionnaire survey concerning genetically modified (GM) food in Britain (n= 396) we similarly find that negative events have a greater impact on trust than positive events. Because public opinion in Britain is skewed in the direction of opposition toward GM food, the pattern of results could either be caused by the fact that negative information is more informative than positive information (a negativity bias) or reflect the influence of people's prior attitudes toward the issue (a confirmatory bias). The results were largely in line with the confirmatory bias hypothesis: participants with clear positive or negative beliefs interpreted events in line with their existing attitude position. However, for participants with intermediate attitudes, negative items still had greater impact than the positive. This latter finding suggests that, congruent with the negativity bias hypothesis, negative information may still be more informative than positive information for undecided people. The study also identified the labeling of GM products, consulting the public, making biotechnology companies liable for any damage, and making a test available to detect GM produce as being particularly important preconditions for maintaining trust in the regulation of agricultural biotechnology.

Exploring the dimensionality of trust in risk regulation.

This article investigates possible differential levels of trust in government regulation across five different risk contexts and the relationship between a number of concepts that might be thought of as comprising distinctive "dimensions" of trust. It appeared that how people perceive government and its policies toward risk regulation was surprisingly similar for each of the five risk cases. A principal-component analysis showed that the various trust items could best be described by two dimensions: a general trust dimension, which was concerned with a wide range of trust-relevant aspects, such as competence, care, fairness, and openness, and a scepticism component that reflects a sceptical view regarding how risk policies are brought about and enacted. Again, the results were surprisingly similar across the five risk cases, as the same solution was found in each of the different samples. It was also examined whether value similarity has an additional value in predicting trust in risk regulation, compared to the more conventional aspects of trust. Based on the two independent trust factors that were found in this study, a typology of trust is proposed that ranges from full trust to a deep type of distrust. It is argued that for a functioning society it could well be more suitable to have critical but involved citizens in many situations.