IPCC Fourth Assessment Report: Climate Change 2007
Climate Change 2007: Working Group II: Impacts, Adaptation and Vulnerability

Industry, settlement and society

Virtually all of the world’s people live in settlements, and many depend on industry, services and infrastructure for jobs, well-being and mobility. For these people, climate change adds a new challenge in assuring sustainable development for societies across the globe. Impacts associated with this challenge will be determined mainly by trends in human systems in future decades as climate conditions exacerbate or ameliorate stresses associated with non-climate systems [7.1.1, 7.4, 7.6, 7.7].

Inherent uncertainties in predicting the path of technological and institutional change and trends in socio-economic development over a period of many decades limit the potential to project future prospects for industry, settlements and society involving considerable climate change from prospects involving relatively little climate change. In many cases, therefore, research to date has tended to focus on vulnerabilities to impacts rather than on projections of impacts of change, saying more about what could happen than about what is expected to happen [7.4].

Key vulnerabilities of industry, settlements and society are most often related to (i) climate phenomena that exceed thresholds for adaptation, related to the rate and magnitude of climate change, particularly extreme weather events and/or abrupt climate change, and (ii) limited access to resources (financial, human, institutional) to cope, rooted in issues of development context (see Table TS.1) [7.4.1, 7.4.3, 7.6, 7.7].

Table TS.1. Selected examples of current and projected climate-change impacts on industry, settlement and society and their interaction with other processes [for full text, see 7.4.3, T7.4]. Orange shading indicates very significant in some areas and/or sectors; yellow indicates significant; pale brown indicates that significance is less clearly established.

Climate driven phenomena  Evidence for current impact/vulnerability Other processes/stresses Projected future impact/vulnerability Zones, groups affected 
a) Changes in extremes 
Tropical cyclones, storm surge Flood and wind casualties and damages; economic losses; transport, tourism; infrastructure (e.g., energy, transport); insurance [7.4.2, 7.4.3, B7.2, 7.5]. Land use/population density in flood-prone areas; flood defences; institutional capacities. Increased vulnerability in storm-prone coastal areas; possible effects on settlements, health, tourism, economic and transportation systems, buildings and infrastructure.  Coastal areas, settlements, and activities; regions and populations with limited capacities and resources; fixed infrastructure; insurance sector. 
Extreme rainfall, riverine floods Erosion/landslides; land flooding; settlements; transportation systems; infrastructure [7.4.2, regional chapters]. Similar to coastal storms plus drainage infrastructure. Similar to coastal storms plus drainage infrastructure. Similar to coastal storms. 
Heat- or cold-waves Effects on human health; social stability; requirements for energy, water and other services (e.g., water or food storage); infrastructure (e.g., energy transportation) [7.2, B7.1,,]. Building design and internal temperature control; social contexts; institutional capacities. Increased vulnerabilities in some regions and populations; health effects; changes in energy requirements. Mid-latitude areas; elderly, very young, and/or very poor populations. 
Drought Water availability; livelihoods, energy generation, migration, transportation in water bodies [,,]. Water systems; competing water uses; energy demand; water demand constraints. Water-resource challenges in affected areas; shifts in locations of population and economic activities; additional investments in water supply. Semi-arid and arid regions; poor areas and populations; areas with human-induced water scarcity. 
b) Changes in means 
Temperature Energy demands and costs; urban air quality; thawing of permafrost soils; tourism and recreation; retail consumption; livelihoods; loss of meltwater [,,,]. Demographic and economic changes; land-use changes; technological innovations; air pollution; institutional capacities.  Shifts in energy demand; worsening of air quality; impacts on settlements and livelihoods depending on meltwater; threats to settlements/infrastructure from thawing permafrost soils in some regions.  Very diverse, but greater vulnerabilities in places and populations with more limited capacities and resources for adaptation. 
Precipitation Agricultural livelihoods; saline intrusion; water infrastructures; tourism; energy supplies [,,].  Competition from other regions/sectors; water resource allocation.  Depending on the region, vulnerabilities in some areas to effects of precipitation increases (e.g., flooding, but could be positive) and in some areas to decreases (see drought above).  Poor regions and populations.  
Sea-level rise  Coastal land uses: flood risk, waterlogging; water infrastructures [,].  Trends in coastal development, settlements and land uses.  Long-term increases in vulnerabilities of low-lying coastal areas.  Same as above.  

Findings about the context for assessing vulnerabilities are as follows.

Climate change vulnerabilities of industry, settlement and society are mainly to extreme weather events rather than to gradual climate change, although gradual changes can be associated with thresholds beyond which impacts become significant (high confidence).

The significance of gradual climate change, e.g., increases in the mean temperature, lies mainly in variability and volatility, including changes in the intensity and frequency of extreme events [7.2, 7.4].

Aside from major extreme events, climate change is seldom the main factor in considering stresses on sustainability (very high confidence).

The significance of climate change (positive or negative) lies in its interactions with other sources of change and stress, and its impacts should be considered in such a multi-cause context [7.1.3, 7.2, 7.4].

Vulnerabilities to climate change depend considerably on relatively specific geographical and sectoral contexts (very high confidence).

They are not reliably estimated by large-scale (aggregate) modelling and estimation [7.2, 7.4].

Climate change impacts spread from directly impacted areas and sectors to other areas and sectors through extensive and complex linkages (very high confidence).

In many cases, total impacts are poorly estimated by considering only direct impacts [7.4].