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Resources: Climate Digest

Climate Digest for July 2009

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Climate science
Adaptation
Risk, uncertainty and decision-making

Climate science

1 Can cosmic rays affect cloud condensation rates by altering new particle formation rates?

A common alternative or additional explanation to the consensus view that greenhouse gas forcing has caused most of the observed change in average global temperature is the influence of cosmic rays. The suggested mechanism through which cosmic rays are thought to influence climate is through influencing cloud formation. There are several plausible mechanisms that could link cosmic rays with clouds, a leading candidate is the ion-aerosol clear-air hypothesis which suggests that an increase in cosmic rays causes an increases in new particle formation increasing cloud condensation nuclei concentrations and consequently low-level cloud cover. This increased cloud cover, in turn reflects more incoming solar radiation and thus has a cooling effect. Conversely, a reduction in cosmic ray flux would be expected to decreased low-level cloud cover and lead to warming.

This paper provides calculations of the potential magnitude of the ion-aerosol clear-air mechanism using a general circulation model with online aerosol microphysics. The simulations suggest that changes in cosmic rays during a solar cycle are two orders of magnitude too small to account for the observed changes in cloud properties. The authors conclude that the hypothesised effect is too small to play a significant role in current climate change

Source: Pierce, J.R. & Adams, P.J. (2009) Can cosmic rays affect cloud condensation nuclei by altering new particle formation rates? Geophysical Research Letters, 36, L09820.

Adaptation

2 Adapting to climate change in The Netherlands: an inventory of climate adaptation options and ranking of alternatives

This paper describes an approach used for a qualitative and quantitative assessment of adaptation options that the authors suggest that, with adjustments to local conditions, would be relevant in other countries. It introduces an inventory and ranking of adaptation options based on stakeholder analysis and expert judgement, and presents some estimates of incremental costs and benefits. Within the context of identified limitations, the authors were able to identify a set of top priorities: in the Netherlands, integrated nature and water management, and risk-based policies rank high, followed by policies aimed at increasing the resilience of housing and infrastructure. The assessment approach taken includes:

identification of adaptation options in The Netherlands based on a literature study and consultations with stakeholders in a sectoral approach (agriculture, forestry, fisheries, water, energy and infrastructure with some information on health, recreation and transport);

qualitative assessment of the characteristics of the options (including overlap, synergy and competition);

definition of criteria, based on expert judgements, that could be used to rank promising and feasible adaptation options;

determining the scores of the options on the basis of the various criteria (stakeholder views sought on the scores);

determining the weights to be used in an interactive multi-criteria analysis for ranking the options (based on expert judgements); and

ranking the options.

It is interesting to note that the authors, although considering the feasibility of implementing the various adaptation options, this issue was not introduced into the multi-criteria analysis. The authors believe feasibility to be substantially different from the questions of what adaptation options would be important to consider – a need to focus on solving the barriers associated with implementation rather than reducing the ranking of a priority adaptation because of these barriers. The aspects of feasibility assessed for each of the adaptation options were institutional, technical and societal (diversity of values at stake) complexities.

The criteria defined by the authors for scoring adaptation options were selected such that: all relevant criteria were included, could be used to judge each adaptation option, were mutually independent (although no-regrets and co-benefits are closely related), did not resulting in double counting; and were consistent with affects occurring over time. The criteria use were:

importance of the option in terms of effectiveness in avoiding damages and thus the expected gross benefits,

urgency of the need to implement or whether the option can be deferred to a later point in time (also consideration of lead time and life time),

no-regret characteristics of the option,

potential co-benefits to other sectors and domains; and

effect on mitigation.

In terms of estimating incremental costs and benefits, the authors found that much of the information needed for a proper analysis is not yet available (knowledge gaps exist, data are missing or their reliability is insufficient). This was particularly the case for indirect and external economic and environmental effects of the options. As such, they were only able to present preliminary and incomplete estimates and suggested that detailed additional research towards improving the estimates was needed.

Source: de Bruin, K., Dellink, R., Ruijs, A., Bolwidt, L., van Buuren, A., Graveland, J., de Groot, R., Kuikman, P., Reinhard, S., Roetter, R., Tassone, V., Verhagen, A. & van Ierland, E. (2009) Adapting to climate change in The Netherlands: an inventory of climate adaptation options and ranking of alternatives. Climatic Change, 95, 23–45.

3 Ranking of national-level adaptation options: an editorial comment

This is an editorial comment on the paper in the same issue. The author comments that the approach taken by de Bruin et al had some particular strengths but also some limitations that require further clarification and research prior to more widespread adoption or adaptation for use in other countries. He goes further and suggests that there are some lessons to be learnt from the approach taken and further considerations in the context of transferability of this approach.

Multi-criteria analysis based on expert judgement can help rank national adaptation options.

In using multi-criteria analysis for this purpose there is a need to more clearly define and strive for enhanced comparability and sectoral balance of the adaptation options to be considered.

The separation of priority and feasibility is a strong point as these criteria cannot be integrated on an objective basis.

Need for a means of synthesising the results for these two dimensions (noted strong conflicts for options in the context of difference in priority scoring and feasibility), and for an increased understanding and consideration of trade-offs between priority and feasibility across sectors and of the sensitivities of these criteria to the approach taken.

The need to consider how to include economic feasibility within such an assessment either as part of the ranking or as an additional feasibility issue.

Prioritisation of adaptation options based on cost-benefit analysis will be limited by the data available (e.g. difficulty in undertaking a comprehensive cost-benefit analysis where much of the required data is insufficient data and there is difficulty in separating incremental adaptation costs from baseline costs).

The need to consider current climate risks within such an assessment.

The need to consider the distributional aspects of climate change, including paying more attention to the equity dimensions of adaptation.

Source: Füssel, H. M. (2009) Ranking of national-level adaptation options. An editorial comment. Climatic Change, 95, 47–51.

Risk, uncertainty and decision-making

4 Believing is seeing: laypeople’s views of future socio-economic and climate change in England and in Italy

This study explores public perceptions of and attitudes to climate change in Norwich (UK) and Rome (Italy). It seeks to understand the effects of providing climatic and socio-economic scenarios for the 2050s on personal attitudes towards climate change.

It points out that although the issue of climate change is clearly understood by a majority of both the UK and Italian population, the desire to act as an individual to mitigate the issue is much more muted. Drawing on the Theory of Cognitive Dissonance (Festinger, 1957) the study seeks closer engagement with its participants and thus provides targeted regional scenarios that the participants can relate to. By categorising the respondents into four typologies, Denying, Uninterested, Doubting and Engaging, the study assesses how the categorisation ties to the individual’s interpretation of climate change.

It finds that personally held beliefs strongly shape acceptance of the scenarios presented and that the length of time over which participants were asked to form a vision of the future (up to the 2050s where IPCC scenarios start to diverge) is longer than participants tend to consider, which is closer to a 20 year time horizon. This leads to the conclusion that tailored, motivating, scientifically robust and transparent scenarios need to be presented to engage with the dual issues of what causes climate change and its importance to individuals.

Source: Lorenzoni, I. Hulme, M. (2009) Believing is seeing: laypeople’s views of future socio-economic and climate change in England and in Italy. Public Understanding of Science 18; 383–400.