P. M. Kelly

Theory and practice in assessing vulnerability to climate change and facilitating adaptation

We discuss approaches to the assessment of vulnerability to climatevariability and change andattempt to clarify the relationship between the concepts of vulnerability andadaptation. In searchof a robust, policy-relevant framework, we define vulnerability in terms ofthe capacity ofindividuals and social groups to respond to, that is, to cope with, recoverfrom or adapt to, anyexternal stress placed on their livelihoods and well-being. The approach thatwe develop placesthe social and economic well-being of society at the centre of the analysis,focussing on thesocio-economic and institutional constraints that limit the capacity torespond. From thisperspective, the vulnerability or security of any group is determined byresource availability andby the entitlement of individuals and groups to call on these resources. Weillustrate theapplication of this approach through the results of field research in coastalVietnam, highlightingshifting patterns of vulnerability to tropical storm impacts at the household-and community-levelin response to the current process of economic renovation and drawingconclusions concerningmeans of supporting the adaptive response to climate stress. Four prioritiesfor action areidentified that would improve the situation of the most exposed members ofmany communities:poverty reduction; risk-spreading through income diversification; respectingcommon propertymanagement rights; and promoting collective security. A sustainable response,we argue, mustalso address the underlying causes of social vulnerability, including theinequitable distributionof resources.

Northern hemisphere surface air temperature variations: 1851–1984

Abstract A new compilation of monthly mean surface air temperature for the Northern Hemisphere for 1851–1984 is presented based on land-based meteorological station data and fixed-position weather ship data. This compilation differs from others in two ways. First, a considerable amount of new data, previously hidden away in archives, has been included, thus improving both spatial and temporal coverage. Second, the station data have been analyzed to assess their homogeneity. Only reliable or corrected station data have been used in calculating area averages. Grid point temperature estimates have been made by interpolating onto a 5° latitude by 10° longitude grid for each month of the 134 years. In the period of best data coverage, 58% of the area of the Northern Hemisphere is covered by the available data network. (The remaining area is mainly ocean too far from land-based stations to warrant extrapolation.) The reliability of hemispheric estimates is assessed for earlier periods when coverage is less than...

Social Vulnerability to Climate Change and the Architecture of Entitlements

The objective of this paper is to outline a conceptual model of vulnerability to climate change as the first step in appraising and understanding the social and economic processes which facilitate and constrain adaptation. Vulnerability as defined here pertains to individuals and social groups. It is the state of individuals, of groups, of communities defined in terms of their ability to cope with and adapt to any external stress placed on their livelihoods and well-being. This proposed approach puts the social and economic well-being of society at the centre of the analysis, thereby reversing the central focus of approaches to climate impact assessment based on impacts on and the adaptability of natural resources or ecosystems and which only subsequently address consequences for human well-being. The vulnerability or security of any group is determined by the availability of resources and, crucially, by the entitlement of individuals and groups to call on these resources. This perspective extends the concept of entitlements developed within neo-classical and institutional economics. Within this conceptual framework, vulnerability can be seen as a socially-constructed phenomenon influenced by institutional and economic dynamics. The study develops proxy indicators of vulnerability related to the structure of economic relations and the entitlements which govern them, and shows how these can be applied to a District in coastal lowland Vietnam. This paper outlines the lessons of such an approach to social vulnerability for the assessment of climate change at the global scale. We argue that the socio-economic and biophysical processes that determine vulnerability are manifest at the local, national, regional and global level but that the state of vulnerability itself is associated with a specific population. Aggregation from one level to another is therefore not appropriate and global-scale analysis is meaningful only in so far as it deals with the vulnerability of the global community itself.

Precipitation fluctuations over northern hemisphere land areas since the mid-19th century

An extensive array of measurements extending back to the mid-19th century was used to investigate large-scale changes in precipitation over Northern Hemisphere land areas. Significant increases in mid-latitude precipitation and concurrent decreases in low-latitude precipitation have occurred over the last 30 to 40 years. Although these large-scale trends are consistent with general circulation model projections of precipitation changes associated with doubled concentrations of atmospheric carbon dioxide, they should be viewed as defining large-scale natural climatic variability. Additional work to refine regional variations and address potential network inhomogeneitics is needed. This study attempts to show secular precipitation fluctuations over hemispheric and continental-scale areas of the Northern Hemisphere.

Climate from tree rings

1. Data acquisition and preparation 2. Data analysis 3. The southern hemisphere 4. The northern hemisphere 5. Climate reconstructions.

Variations in Surface Air Temperatures: Part 1. Northern Hemisphere, 1881–1980

Abstract We have produced, using objective techniques, a long-term series of average Northern Hemisphere temperatures based on monthly mean station data gridded on a 5° latitude by 10° longitude grid. Difficulties in the estimation of this parameter are discussed, deficiencies in the currently available data base and possible effects on the estimated average are described, and monthly mean data are presented. Long-term trends and extremes are identified in the annual and seasonal data. All seasons show similar long-term trends, but there are noticeable differences on time scales of 10 years and less. For example, for winter temperature, the early 20th century warming peaked during the 1940s whereas the maximum in the other seasons was in the previous decade. Both the magnitude of the long-term trends and the year-to-year variability has been greatest in winter. There is evidence that the long-term cooling that characterized the 1940s, 1950s and 1960s has ended. Warming began in the mid to late 1960s ...

Variations in Surface Air Temperatures: Part 2. Arctic Regions, 1881–1980

Abstract We describe annual and seasonal changes in air temperatures over high latitudes of the Northern Hemisphere during the period 1881–1980. Trends (that is, fluctuations on time scales greater than 20 years) in the average temperature of the Arctic are compared with those of the Northern Hemisphere. Seasonal and regional departures from the long-term trends in the average temperature of the Arctic are identified. Spatial patterns of variation in the Arctic temperature field are determined by principal component analysis and the major characteristics of the time series of the dominant patterns are summarized. Trends in Arctic temperatures have been broadly similar to those for the Northern Hemisphere during the study period. The Arctic variations were, however, greater in magnitude and more rapid. The spatial pattern of change associated with the trend in Arctic temperatures is clearly identified by principal component analysis. It shows that the trends have, in general, been Arctic-wide, but that cer...

Natural resource management in mitigating climate impacts: the example of mangrove restoration in Vietnam

Abstract The risk that tropical storm occurrence may alter as a result of global warming presents coastal managers, particularly in vulnerable areas, with a serious challenge. Many countries are hard-pressed to protect their coastal resources against present-day hazards, let alone any increased threat in the future. Moreover, the threat posed by climate change is uncertain making the increased costs of protection difficult to justify. Here, we examine one management strategy, based on the rehabilitation of the mangrove ecosystem, which may provide a dual, “winwin” benefit in improving the livelihood of local resource users as well as enhancing sea defences. The strategy, therefore, represents a precautionary approach to climate impact mitigation. This paper quantifies the economic benefits of mangrove rehabilitation undertaken, inter alia, to enhance sea defence systems in three coastal Districts of northern Vietnam. The results of the analysis show that mangrove rehabilitation can be desirable from an economic perspective based solely on the direct use benefits by local communities. Such activities have even higher benefit cost ratios with the inclusion of the indirect benefits resulting from the avoided maintenance cost for the sea dike system which the mangrove stands protect from coastal storm surges.

Holocene climatic change, 14C wiggles and variations in solar irradiance

Evidence from the advances and retreats of alpine glaciers during the Holocene suggests that there were at least 14 century-timescale cool periods similar to the recent Little Ice Age. Here, we examine the hypothesis that these cool periods were caused by reductions in solar irradiance. A statistically significant correlation is found between the global glacial advance and retreat chronology of Röthlisberger and variations in atmospheric 14C concentration. A simple energy-balance climate model is used to show that the mean reduction of solar irradiance during times of maximum 14C anomaly like the Maunder Minimum would have to have been between 0.22 and 0.55 % to have caused these cool periods. If a similar solar irradiance perturbation began early in the 21st century, the associated climate effects would be noticeable, but still considerably less than those expected to result from future greenhouse gas concentration increases.

The spatial response of the climate system to explosive volcanic eruptions

Determining the spatial response of the climate system to volcanic forcing is of importance in the development of short-term climate prediction and in the assesment of anthropogenic factors such as global warming. The June 1991 eruption of the Phillippine volcano, Mount Pinatubo, provides an important opportunity to test existing understanding and extend previous emperical analyses of volcanic effect. We identify the spatial climate response to historic eruptions in the surface air temperature and mean-sea- level pressure record and use this information to assess the impact of the Pinatubo eruption. The Pinatubo eruption clearly generated significant global cooling during the years after the event. The magnitude and timing of the cooling is similar to that associated with previous equatorial eruptions. There is good agreement between the spatial patterns of tempurature and circulation anomalies associated with the historic eruptions and those following the Mount Pinatubo event. Evidence of limited higher latitude warming and a major change in the atmospheric circulation is found over the Northern Hemisphere during the first winter after the equatorial eruptions analysed, followed by widespread cooling, but limited change in the atmosphere circulation, during the subsquent 2 years.