3.3.3 Especially affected systems, sectors and regions

Some systems, sectors and regions are likely to be especially affected by climate change.^[18] {WGII TS.4.5}

Systems and sectors: {WGII TS.4.5}

• particular ecosystems:

• terrestrial: tundra, boreal forest and mountain regions because of sensitivity to warming; mediterranean-type ecosystems because of reduction in rainfall; and tropical rainforests where precipitation declines
• coastal: mangroves and salt marshes, due to multiple stresses
• marine: coral reefs due to multiple stresses; the sea-ice biome because of sensitivity to warming

• water resources in some dry regions at mid-latitudes^[19] and in the dry tropics, due to changes in rainfall and evapotranspiration, and in areas dependent on snow and ice melt
• agriculture in low latitudes, due to reduced water availability
• low-lying coastal systems, due to threat of sea level rise and increased risk from extreme weather events
• human health in populations with low adaptive capacity.

Regions: {WGII TS.4.5}

• the Arctic, because of the impacts of high rates of projected warming on natural systems and human communities
• Africa, because of low adaptive capacity and projected climate change impacts
• small islands, where there is high exposure of population and infrastructure to projected climate change impacts
• Asian and African megadeltas, due to large populations and high exposure to sea level rise, storm surges and river flooding.

Within other areas, even those with high incomes, some people (such as the poor, young children and the elderly) can be particularly at risk, and also some areas and some activities. {WGII 7.1, 7.2, 7.4, 8.2, 8.4, TS.4.5}