Page 25 - 全球气候变化及其影响Global Climate Change and Its Impacts-185×260

Chapter 1 Scientific Basis of Global Climate Change

sphere, altering atmospheric composition and climate. Sulfides can form aerosols that reflect
solar radiation, causing short-term cooling, while carbon dioxide acts as a greenhouse gas
that may lead to long-term warming.
【2】Solar Radiation Variation
Changes in solar radiation affect Earth’s energy balance and consequently influence cli-
mate. For instance, periodic variations in solar activity (e.g., sunspot cycles) may contribute
to short-term climate fluctuations.
【3】Synergistic Effects Between Biogeochemical Cycles and Climate Change
Complex synergies exist between biogeochemical cycles and climate change. For ex-
ample, global warming may increase the frequency of forest fires, further elevating carbon
dioxide emissions. Meanwhile, climate change could alter plant growth cycles and soil mi-
crobial activity, impacting carbon and nitrogen cycling.

Section 3 Anthropogenic Influences on Climate

Human activities have exerted profound impacts on the climate system, particularly
through environmental pressures caused by greenhouse gas emissions, land-use changes,
and other industrial processes. By analyzing the mechanisms of these anthropogenic factors
and their long-term climatic effects, we can gain deeper insights into current global warming
trends and provide scientific foundations for developing effective mitigation strategies.

I. Greenhouse Gas Emissions

Greenhouse Gases (GHGs) refer to atmospheric gases capable of absorbing and emit-
ting infrared radiation, forming a “greenhouse effect” that maintains Earth’s surface tempera-
ture at levels suitable for life. However, since the Industrial Revolution, the intensification of
human activities—particularly extensive fossil fuel combustion and agricultural expansion—
has caused dramatic increases in atmospheric concentrations of major GHGs such as carbon
dioxide (CO ), methane (CH ), and nitrous oxide (N O). This has significantly amplified the
2
4
2
natural greenhouse effect, driving rapid increases in global average temperatures.
（A）Carbon Dioxide (CO )
2
As one of the primary greenhouse gases, carbon dioxide exerts significant impacts on
Earth’s climate system. It primarily originates from human activities, particularly the con-
sumption of fossil fuels (including coal, petroleum, and natural gas) and CO released during
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limestone decomposition in cement production. According to data from the International En-
ergy Agency (IEA), global CO emissions from these activities reached approximately 36.8
2
billion tons in 2019. Among these, the power generation and heating sector constituted the
largest emission source, followed by transportation, manufacturing activities, and building
operations.

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