Page 26 - 全球气候变化及其影响Global Climate Change and Its Impacts-185×260

Global Climate Change and Its Impacts

With global economic expansion and population growth, CO emission levels continue
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to climb, recognized as a key driver behind the rise in global temperatures. Additionally, nat-
uralcarbon sinks such asThe reduction of forests due to deforestation, along with other types
of land use changes such as farmland reclamation or urban expansion, has led to significant
amounts of previously sequestered carbon being released into the atmosphere, thereby con-
tributing to the increasing trend of carbon dioxide concentration. This continuously rising
CO level is altering Earth’s energybalance and causing profound environmental impacts,
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including increased frequency of extreme weather events and rising sea levels. Consequent-
ly, controlling and reducing CO emissions has become one of the core tasks in addressing
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climate change challenges.
Methane (CH )
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Methane, as a greenhouse gas, although having a shorter atmospheric lifetime, pos-
sesseswarming potentialfar exceeds that of carbon dioxide, estimated to be approximately 25
times that of CO over a 100-year time frame. The primary emission sources of this gas span
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multiple sectors: enteric fermentation in livestock and rice paddy management in agriculture;
fugitive emissions during extraction, processing, and transportation in the fossil fuel indus-
try; solid waste treatment facilities such as landfills; and wetland releases in natural ecosys-
tems.
Even though the atmospheric concentration of methane is far lower than that of carbon
dioxide, its impact on global warming should not be underestimated. According to records,
methane levels in the atmosphere have increased by approximately 150% over the past two
centuries. This not only directly contributes to global temperature rise but may also trigger
other environmental effects. For instance, it may accelerate the thawing process of perma-
frost, which contains vast amounts of organic material that, once thawed, decomposes and
releases more methane, creating a positive feedback mechanism that further drives the pace
and intensity of climate change. Therefore, although methane exists in relatively smaller
absolute quantities, its role in global climate system changes is crucial, and controlling meth-
ane emissions remains one of the key strategies for mitigating global warming.
（3）Nitrous Oxide（N O）
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Nitrous oxide (N O), with the chemical formula N O, is not only a trace gas in the at-
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mosphere but also a significant greenhouse gas that cannot be overlooked. Its remarkable
greenhouse effect is striking, with scientific estimates showing that over the same time scale
(a 100-year period), nitrous oxide’s global warming potential is approximately 298 times that
of carbon dioxide (CO ). This means that although the atmospheric concentration of nitrous
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oxide is much lower than that of carbon dioxide, its contribution to global climate warming
remains substantial.
The primary sources of nitrous oxide are diverse, with agricultural activities being one
of the major emission contributors. During agricultural production, the use of chemical and
organic fertilizers inevitably leads to N O generation. These fertilizers release nitrous oxide
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