Our ability to answer questions about climate change, vulnerability, and adaptation on the basis of research evidence is very limited for human settlements, energy, and industry. Energy has been regarded mainly as an issue for Working Group III, related more to causes of climate change than to impacts. Industry generally has been considered relatively insensitive to most primary climate change impacts, although some sectors (e.g., agroindustry) are dependent on supply streams that could be vulnerable to climate change impacts. Impacts of climate change on human settlements are hard to forecast, at least partly because the ability to project climate change at an urban or smaller scale has been so limited. As a result, more research is needed on impacts and adaptations in human settlements. Several activities also have been developed by governments in the area of “sustainable communities,” which are designed primarily to reduce the impact of human settlements on the environment. Many of the actions recommended also reduce the vulnerability of settlements to global warming. Some areas of information required to support these programs have been identified by organizations such as the United Nations’ International Decade for Natural Disaster Reduction (IDNDR Secretariat), the ICLEI, and the U.S. President’s Council on Sustainable Development. Others were identified during preparation of the FAR, SAR, RICC, and this report.

Table 7-3: Matrix of synergistic effects, by type of effect and settlement and industry type.a,b
Primary Impact Mechanism	Migration	Synergistic Impact Flooding, Landslides, Fire	Mechanism, Settlement Air and Water Pollution	Type or Industry Human Health	Energy, Water, Other Resources
Migration	—	U,RCS	U,RCS	U,RCS	U,E,A
Flooding , Landslides, Fire	U,RCS,TR	—	U,RD,RCS	U,RD,RCS	U,RD,RCS,TR
Air and Water Pollution	U,RCS	U,RD,RCS,RE	—	U,RD,RCS,RE,A	RE
Human Health	U	U,RD,RCS	U,RC,RE	—	U
Energy, Water, Other Resources	U,RD,RCS,A	U,RD,RCS	U,RD,RCS	—	—
a Settlement types: RD = resource-dependent, RCS = riverine, coastal, steeplands, U = urban. b Industry types: A = agroindustry, E = energy, TR = transportation, RE = recreation.

The highest priority needs for research on impacts, adaptation, and vulnerabilities in human settlements are as follows:

• A much larger number and variety of bottom-up empirical case studies of climate change impacts and possible responses in settlements in the developing and industrialized world
• More reliable climate change scenarios at the scale of urban and even smaller areas
• Improved understanding of how climate change interacts with integrated multiple-stress contexts in human settlements, including possible ramifications of global urbanization
• Improved understanding of adaptation pathways, their costs and benefits, and what can reasonably be expected from them, especially in resource-constrained developing regions (includes autonomous and planned adaptation, as well as traditional and local adaptation; for example, analysis of water demand lags analysis of energy use in most countries)
• Improved understanding of the effects of climate on human migration and the effects of migration on source and destination settlements
• Improved understanding of critical climate change vulnerabilities in settlements, including conceivable low-probability, high-impact effects of climate change (need for continuing research and capacity-building efforts to improve preparedness and strengthen early warning and other mitigation aspects; establishment of a tropical cyclone landfall program is regarded as a logical vehicle for carrying research and development initiatives into the 21st century)
• Better understanding of the particular vulnerabilities of livelihoods and settlements of low-income and marginalized groups
• Improved understanding of the implications of climate variability and change for the well-being of human settlements as they relate to other sectors, other places, and the broader sustainable development process
• Improved understanding of the cascading of climate change through primary, secondary, and tertiary impacts within human settlements (a conclusion of the RICC, but not yet addressed effectively)
• Improved analytical capability to incorporate uncertainty, ambiguity, and indeterminacy in assessments of impacts and response strategies, at least partly by strengthening the science base for integrating quantitative and qualitative analysis, including undertakings such as scenario development and stakeholder participation.

Other key challenges to be faced include development of essential scientific and technical capacity in vulnerable regions, establishment and maintenance of adequate meteorological and hydrological monitoring networks, and improvement of seasonal and interannual prediction.

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