Page 106 - 全球气候变化及其影响Global Climate Change and Its Impacts-185×260

Global Climate Change and Its Impacts

factorsthe population in areas potentially submerged by sea-level rise is 100,000, then the
population exposure degree of the region is (100,000 ÷ 1,000,000) × 100% = 10%. The high-
er this value, the greater the degree to which the population in the region is exposed to the
impacts of climate change, indicating an increased risk of adverse climate change effects on
the population.
In the assessment of economic activity exposureconsiderationsIn , due to significant
differences in climate change sensitivity across industries, detailed analysis should be con-
ducted separately for different industries. Taking the agricultural sector as an example, the
first step is to thoroughly investigate and clarify the proportion of agricultural output in the
total regional output value. This requires comprehensive analysis of the regional economic
structure, statistical collection of output data from various industries, and calculation of agri-
culture’s share. Generally, in regions where agriculture dominates, agricultural output often
accounts for a higher proportion of total regional output. Subsequently, in-depth analysis
should be conducted on output losses caused by climate change factors (such as abnormal
precipitation fluctuations and significant temperature variations) affecting agricultural pro-
duction. The impacts of climate change on agriculture are multifaceted: excessive rainfall
may cause floods that submerge farmland and damage crops, leading to reduced yields or
total crop failure; insufficient rainfall may result in drought that affects crop water supply,
similarly reducing yields. Extreme temperatures (both high and low) can also adversely
affect crop growth and development. For instance, abnormal low temperatures during flow-
ering periods may hinder pollination and consequently reduce yields. Through comparative
analysis of multi-year agricultural production data and concurrent climate change data, com-
bined with field research and evaluation by agricultural experts, we can estimate the propor-
tion of agricultural output losses caused by climate change. By multiplying the proportion of
agricultural output in total regional output with the loss ratio caused by climate change, we
obtain the exposure level of agricultural economic activitiesexposure level. For example, the
agricultural output of a regionaccounts for30% of the total regional output. Afterassessment,
climate changehas caused a 20% loss in agricultural output. Thus, the exposure level of ag-
ricultural economic activities in this region is 30%×20% = 6%. The higher this value, the
greater the exposure level of agricultural economic activities to climate change impacts in
the region, indicating higher risks faced by the agricultural economy.
In the assessment of natural ecosystem exposure, the focus should be on the area chang-
es of specific ecosystem types (such as vast forests, ecologically significant wetlands, etc.)
caused by climate change. When climate change occurs, forest ecosystems may be affected
by multiple factors. For instance, rising temperatures may increase the frequency of forest
fires, potentially destroying large areas of woodland; simultaneously, climate change could
trigger pest outbreaks, where originally minor threats might proliferate under altered climatic
conditions, causing severe damage to trees and reducing forest area. Wetland ecosystems are
similarly sensitive to climate change, as altered precipitation patterns may lead to abnormal

• 98 •