IPCC Report.pdf - Adam Curry

Chapter 4Changes in Impacts of Climate Extremes: Human Systems and Ecosystemsdensity and lower birth rate than any other continent. Nonetheless, exposure to climate extremes in Europe hasincreased whereas vulnerability has decreased as a result of implementation of policy, regulations, risk prevention, andrisk management. Urban heat islands pose an additional risk to urban inhabitants, most affecting the elderly, ill, andsocially isolated. [4.3.5.1, 4.3.6, 4.4.5]Transportation, infrastructure, water, and tourism are sectors sensitive to climate extremes. Transportinfrastructure is vulnerable to extremes in temperature, precipitation/river floods, and storm surges, which can lead todamage in road, rail, airports, and ports, and electricity transmission infrastructure is also vulnerable to extreme stormevents. The tourism sector is sensitive to climate, given that climate is the principal driver of global seasonality intourism demand. [4.3.5.2, 4.3.5.3]Agriculture is also an economic sector exposed and vulnerable to climate extremes. The economies of manydeveloping countries rely heavily on agriculture, dominated by small-scale and subsistence farming, and livelihoods inthis sector are especially exposed to climate extremes. Droughts in Africa, especially since the end of the 1960s, haveimpacted agriculture, with substantial famine resulting. [4.3.4, 4.4.2]Coastal settlements in both developed and developing countries are exposed and vulnerable to climateextremes. For example, the major factor increasing the vulnerability and exposure of North America to hurricanes isthe growth in population and increase in property values, particularly along the Gulf and Atlantic coasts of the UnitedStates. Small island states are particularly vulnerable to climate extremes, especially where urban centers and/or islandinfrastructure predominate in coastal locations. Asia’s mega-deltas are also exposed to extreme events such as floodingand have vulnerable populations in expanding urban areas. Mountain settlements are also exposed and vulnerableto climate extremes. [4.3.5.1, 4.4.3, 4.4.6, 4.4.9, 4.4.10]In many regions, the main drivers of future increases in economic losses due to some climate extremes willbe socioeconomic in nature (medium confidence, based on medium agreement, limited evidence). Thefrequency and intensity of extreme weather and climate events are only one factor that affects risks, but few studieshave specifically quantified the effects of changes in population, exposure of people and assets, and vulnerability asdeterminants of loss. However, these studies generally underline the important role of projected changes (increases) inpopulation and capital at risk. Additionally, some researchers argue that poorer developing countries and smallereconomies are more likely to suffer more from future disasters than developed countries, especially in relation toextreme impacts. [4.5.2, 4.5.4.2]Increases in exposure will result in higher direct economic losses from tropical cyclones. Losses willdepend on future changes in tropical cyclone frequency and intensity (high confidence). Overall losses due toextratropical cyclones will also increase, with possible decreases or no change in some areas (medium confidence).Although future flood losses in many locations will increase in the absence of additional protection measures (highagreement, medium evidence), the size of the estimated change is highly variable, depending on location, climatescenarios used, and methods used to assess impacts on river flow and flood occurrence. [4.5.4.2]Extreme events will have greater impacts on sectors with closer links to climate, such as water, agricultureand food security, forestry, health, and tourism. For example, while it is not currently possible to reliably projectspecific changes at the catchment scale, there is high confidence that changes in climate have the potential to seriouslyaffect water management systems. However, climate change is in many instances only one of the drivers of futurechanges in supply reliability, and is not necessarily the most important driver at the local scale. The impacts of changesin flood characteristics are also highly dependent on how climate changes in the future, and as noted in Section 3.5.2,there is low confidence in projected changes in flood magnitude or frequency. However, based on the availableliterature, there is high confidence that, in some places, climate change has the potential to substantially affect floodlosses. Climate-related extremes are also expected to produce large impacts on infrastructure, although detailed235