Page 107 - 全球气候变化及其影响Global Climate Change and Its Impacts-185×260

Chapter Three Impacts of Global Climate Change

water level fluctuations - excessively high levels might submerge wetland vegetation, while
low levels could cause wetland desiccation, both resulting in wetland shrinkage. By utiliz-
ing satellite remote sensing technology and ground monitoring data, precise measurements
of ecosystem area changes across different periods can be obtained. For calculating natural
ecosystem exposure, the formula is: (Reduced ecosystem area ÷ Total regional area) × 100%.
For example, in a region with a total area of 1000 km² where forest area has decreased by
50 km² due to climate change, the forest ecosystem exposure would be (50 ÷ 1000) × 100%
= 5%. Higher values indicate greater exposure of natural ecosystems to climate change im-
pacts, implying increased risks to ecosystem stability and functionality.
(2) Sensitivity Indicators and Their Calculation Methods
As another crucial indicator for assessing regional climate change vulnerability, sensi-
tivity is primarily used to measure the degree of response and magnitude of change in various
systems within a region to climate variations. In agricultural systems, the sensitivity of crop
yields to temperature and precipitation changes is one of the most critical evaluation metrics.
To accurately quantify this sensitivity, long-term, continuous, and systematic observation
and data collection are required. In practice, researchers establish observation points across
multiple agricultural production areas to consistently record crop yield data. Simultaneously,
professional meteorological monitoring equipment is employed to collect temperature and
precipitation data from surrounding areas of these observation points. Through in-depth anal-
ysis of multi-year crop yield data alongside corresponding temperature and precipitation re-
cords, researchers investigate intrinsic relationships and patterns of variation. Generally, crop
growth requires specific ranges of temperature and precipitation—when these parameters
deviate from optimal ranges, crop yields are often affected. For instance, for thermophilic
and hygrophilous crops like rice, sustained temperatures below optimal levels during critical
growth stages may lead to stunted growth and incomplete grain filling, resulting in signif-
icant yield reductions. Similarly, insufficient precipitation to meet water requirements can
impair normal growth and development, thereby lowering yields. Through statistical analysis
of extensive data combined with practical agricultural production experience, the sensitivity
of crop yields to temperature and precipitation changes can be reasonably determined. For
example, if studies show that a 1℃ temperature decrease correlates with a 5% average yield
reduction for rice in a particular region, this indicates relatively high sensitivity of rice yields
to temperature changes in that area.
In the context of water resource systems, the sensitivity of river water volume to precip-
itation changes constitutes a key focus of assessment. As the primary replenishment source
for river water volume, precipitation variations directly exert significant impacts on river
flows. When precipitation increases, enhanced replenishment typically elevates river water
volumes; conversely, decreased precipitation may lead to reduced river flows. To accurate-
ly measure this sensitivity, long-term monitoring and comparative analysis of river water
volumes and precipitation patterns across different periods are essential. Practically, this in-

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