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Table SPM-1. (WGII) Examples of possible impacts of climate change due to changes in extreme weather and climate events

based on projections to the mid- to late 21st century. These do not take into account any changes or developments in adaptive capacity. Examples of all entries are to be found in chapters in the full Assessment (see source at top of columns). The first two columns of the table (shaded yellow) are taken directly from the Working Group I Fourth Assessment (Table SPM-2). The likelihood estimates in Column 2 relate to the phenomena listed in Column 1.

Phenomenona and direction of trend Likelihood of future trends based on projections for 21st century using SRES scenarios Examples of major projected impacts by sector
Agriculture, forestry and ecosystems [4.4, 5.4] Water ressources [3.4] Human health [8.2, 8.4] Industry, settlement and society [7.4]
a See Working Group I Fourth Assessment Table 3.7 for further details regarding definitions.
b Warming of the most extreme days and nights each year.
c Extreme high sea level depends on average sea level and on regional weather systems. It is defined as the highest 1% of hourly values of observed sea level at a station for a given reference period.
d In all scenarios, the projected global average sea level at 2100 is higher than in the reference period [Working Group I Fourth Assessment 10.6]. The effect of changes in regional weather systems on sea level extremes has not been assessed.
Over most land areas, warmer and fewer cold days and nights, warmer and more frequent hot days and nights Virtually certainb Increased yields in colder environments; decreased yields in warmer environments; increased insect outbreaks Effects on water resources relying on snow melt; effects on some water supplies Reduced human mortality from decreased cold exposure Reduced energy demand for heating; increased demand for cooling; declining air quality in cities; reduced disruption to transport due to snow, ice; effects on winter tourism
Warm spells/heat waves. Frequency increases over most land areas Very likely Reduced yields in warmer regions due to heat stress; increased danger of wildfire Increased water demand; water quality problems, e.g., algal blooms Increased risk of heat-related mortality, especially for the elderly, chronically sick, very young and socially- isolated Reduction in quality of life for people in warm areas without appropriate housing; impacts on the elderly, very young and poor
Heavy precipitation events. Frequency increases over most areas Very likely Damage to crops; soil erosion, inability to cultivate land due to waterlogging of soils Adverse effects on quality of surface and groundwater; contamination of water supply; water scarcity may be relieved Increased risk of deaths, injuries and infectious, respiratory and skin diseases Disruption of settlements, commerce, transport and societies due to flooding; pressures on urban and rural infrastructures; loss of property
Area affected by drought increases Likely Land degradation; lower yields/crop damage and failure; increased livestock deaths; increased risk of wildfire More widespread water stress Increased risk of food and water shortage; increased risk of malnutrition; increased risk of water- and food- borne diseases Water shortages for settlements, industry and societies; reduced hydropower generation potentials; potential for population migration
Intense tropical cyclone activity increases Likely Damage to crops; windthrow (uprooting) of trees; damage to coral reefs Power outages causing disruption of public water supply Increased risk of deaths, injuries, water- and food- borne diseases; post-traumatic stress disorders Disruption by flood and high winds; withdrawal of risk coverage in vulnerable areas by private insurers, potential for population migrations, loss of property
Increased incidence of extreme high sea level (excludes tsunamis)c Likely d Salinisation of irrigation water, estuaries and freshwater systems Decreased freshwater availability due to saltwater intrusion Increased risk of deaths and injuries by drowning in floods; migration- related health effects Costs of coastal protection versus costs of land-use relocation; potential for movement of populations and infrastructure; also see tropical cyclones above

Source: IPCC Climate Change 2007:  Impacts, Adaptation and Vulnerability, Summary for Policymakers (2007), p18

Related publication:
Climate Change (2007) homeClimate Change 2007 Update
Other Figures & Tables on this publication:

Figure SPM-1. (WGI) Changes in Greenhouse Gases from Ice-core and Modern Data

Figure SPM-2. (WGI) Radiative Forcing Components

Figure SPM-3. (WGI) Changes in Temperatures, Sea Level and Snow Cover between 1850 and 2010

Figure SPM-4. (WGI) Global and Continental Temperature Change

Figure SPM-5. (WGI) Multi-model Averages and Assessed Ranges for Surface Warming

Figure SPM-6. (WGI) AOGCM Projections of Surface Temperatures

Figure SPM-7. (WGI) Projected Patterns of Precipitation Changes

Figure SPM-1. (WGII) Changes in physical and biological systems and surface temperature 1970-2004

Figure SPM-2. (WGII) Key impacts as a function of increasing global average temperature change

Figure SPM-1. (WGIII) Emissions of different greenhouse gases 1970-2004

Figure SPM-2. (WGIII) Relative global development of indicators of income, energy supply, CO2 emissions and population for 1970 to 2004

Figure SPM-3a. (WGIII) Distribution of regional per capita greenhouse gas emissions

Figure SPM-3b. (WGIII) Distribution of regional greenhouse gas emissions per unit of income

Figure SPM-4. (WGIII) Global greenhouse gas emissions for 2000, 2030 and 2100

Figure SPM-5a/5b. (WGIII) Estimated global economic mitigation potential

Figure SPM-6. (WGIII) Estimated economic mitigation potential in 2030 as a function of carbon price

Figure SPM-7. (WGIII) Emissions pathways of mitigation scenarios for alternative categories of stabilization levels

Figure SPM-8. (WGIII) Relationship between stabilization scenario categories and equilibrium global mean temperature change

Figure SPM-9. (WGIII) Cumulative emissions reductions for alternative mitigation measures for 2000 to 2030 (left-hand panel) and for 2000-2100 (right-hand panel)

Global greenhouse gas emissions 1970-2004

Table SPM-1. (WGI) Observed rate of sea level rise and estimated contributions from different sources.

Table SPM-2. (WGI) Recent trends, assessment of human influence on the trend, and projections for extreme weather events for which there is an observed late 20th century trend.

Table SPM-3. (WGI) Projected globally averaged surface warming and sea level rise at the end of the 21st century.

Table SPM-1. (WGII) Examples of possible impacts of climate change due to changes in extreme weather and climate events based on projections to the mid- to late 21st century. These do not take into account any changes or developments in adaptive capacity. Examples of all entries are to be found in chapters in the full Assessment (see source at top of columns). The first two columns of the table (shaded yellow) are taken directly from the Working Group I Fourth Assessment (Table SPM-2). The likelihood estimates in Column 2 relate to the phenomena listed in Column 1.

Table SPM-4. (WGIII) Estimated global macro-economic costs in 2030a for least-cost trajectories towards different long-term stabilization levels.b,c

Table SPM-5. (WGIII) Characteristics of post-TAR stabilization scenarios [Table TS 2, 3.10]a

Table SPM-6. (WGIII) Estimated global macro-economic costs in 2050 relative to the baseline for least-cost trajectories towards different long-term stabilization targetsa [3.3, 13.3]

Table SPM-7. (WGIII) Selected sectoral policies, measures and instruments that have shown to be environmentally effective in the respective sector in at least a number of national cases.

Table SPM-1. (WGIII) Global economic mitigation potential in 2030 estimated from bottom-up studies.

Table SPM-2. (WGIII) Global economic mitigation potential in 2030 estimated from top-down studies.

Table SPM-3. (WGIII) Key mitigation technologies and practices by sector. Sectors and technologies are listed in no particular order. Non-technological practices, such as lifestyle changes, which are cross-cutting, are not included in this table (but are addressed in paragraph 7 in this SPM).

Figure SPM-2. (WGII) Key impacts as a function of increasing global average temperature change

Figure SPM-6. (WGIII) Estimated economic mitigation potential in 2030 as a function of carbon price

Likelihood

The Emission Scenarios of the IPCC Special Report on Emission Scenarios (SRES)

Box SPM-2 (WGIII) Mitigation potential and analytical approaches

Box SPM-3 (WGIII) Assumptions in studies on mitigation portfolios and macro-economic costs

Box SPM-4 (WGIII) Modelling induced technological change

Parties & Observers of the UNFCCC