Impacts of climate change environmental security

As described above, environmental security is measured with four indicators to represent the health of aquatic life and wildlife, water for domestic use and the overall sus-tainability of the system. Environmental demands for wildlife refuges are consistently met both under conditions of existing climate and climate change. Only in 2070-2099 under the climate change scenario are ecosystem demands unmet, and even then only for on average 1.5% of the time. Average unmet urban demand under existing climate and with climate change is approximately 23 X 106 m3 and 34 X 106 m3, respectively, for the period 2010-2039. This represents an unmet demand of 7% without climate change and 10% with climate change in 2010-2039 and 12% in 2070-2099.

An important indicator of environmental security is the change in groundwater storage in the system as a measure of sustainability. There is significant groundwater storage in the Sacramento Basin, which is steadily being depleted in these scenarios, as illustrated in Fig. 11.9. Clearly this pattern of water use is not sustainable. Furthermore, in as much as groundwater usage is driven by agriculture demands and surface water availability, the impacts of climate change alone (without land use changes) are substantial. Under the B2 climate scenario, which in general is more temperate, groundwater storage declines, although not as rapidly as in the A2 climate scenario.

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