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Global Climate Change and Its Impacts

mate conditions by influencing ocean circulation, atmospheric circulation, and precipitation
patterns. For example, the prediction of ENSO events holds great importance for seasonal
precipitation and temperature forecasts, enabling scientific decision-making in fields such as
agriculture, water resource management, and disaster prevention. The predictions of PDO
and NAO also provide important reference value for regional climate change and extreme
weather event forecasting.

5. Role of Biogeochemical Cycles

Biogeochemical cycles are crucial components of the Earth system, exerting pro-
found impacts on the global climate system by regulating material exchange among the
atmosphere, land, and oceans. The carbon and nitrogen cycles are two of the most critical
processes, not only controlling atmospheric greenhouse gas concentrations but also influ-
encing long-term climate changes and short-term fluctuations through complex interactions.
Terrestrial and marine ecosystems play a key role in regulating atmospheric composition by
absorbing and releasing greenhouse gases such as carbon dioxide. However, human activities
like deforestation, land-use changes, and ocean acidification are significantly disrupting these
natural cycles, thereby exerting non-negligible impacts on the climate system. Additionally,
biogeochemical cycles interact with other natural drivers (such as volcanic activity and solar
radiation variations) to collectively shape Earth’s climatic characteristics.
(1) The Role of Carbon Cycle
The carbon cycle is a fundamental process within the Earth systemmostOne of the core
biogeochemical processes that directly influences global climate by regulating atmospheric
carbon dioxide (CO ) concentrations. The carbon cycle mainly includes the following com-
2
ponents:
【1】Atmosphere-Land Exchange
Terrestrial ecosystems (such as forests, grasslands, wetlands) absorb atmospheric CO
2
through photosynthesis and convert it into organic matter. Carbon absorbed by plants during
growth isreleased back into the atmosphere throughrespiration and decomposition. Forests
are crucial components of the terrestrial carbon cycle, particularly tropical rainforests which
absorb massive amounts of CO annually, making them one of Earth’s most importantcarbon
2
sinks。
【2】Atmosphere-Ocean Exchange
The ocean is the largest carbon sink on Earth, regulating atmospheric carbon concentra-
tions by dissolving and absorbing carbon dioxide from the atmosphere. Carbon absorption in
the ocean’s surface layer primarily occurs through physical processes (such as wind-driven
gas exchange) and biological processes (such as photosynthesis by phytoplankton). Howev-
er, the ocean’s capacity to absorb carbon dioxide is limited, and excessive carbon input leads
to ocean acidification, subsequently affecting marine ecosystem health.

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