版权归作者所有，转载请注明出处
南太平洋地区海平面上升的原因总结
Sea-level rise in the South Pacific is a serious climate change issue that affects the lives of countless people. The problem is driven by several complex factors. In this paper, I will summarize and analyze the three main causes of sea level rise in the South Pacific region, including global climate change, geological tectonics, and human activities. After that, I will analyze these causes in detail in several articles in my public website.
I. Global climate change
Global climate change is the most significant cause of sea level rise in the South Pacific, and according to my summary, there are three main reasons why global climate change is causing sea level rise in the South Pacific:
1、Greenhouse gas emissions
Emissions of greenhouse gases such as carbon dioxide (CO2), methane (CH4), and nitrogen dioxide (N2O) are a major contributor to the greenhouse effect, where they build up in the atmosphere and contribute to the warming of the planet.
Human activities, especially the burning of fossil fuels, industrial processes and deforestation, release large quantities of greenhouse gases. These gases absorb a portion of the radiation from the Earth's surface during the day and continue to transfer the absorbed heat to the atmosphere, leading to an increase in atmospheric temperatures. According to the simplest principle of thermal expansion and contraction, the oceans will experience thermal expansion as a result of the increase in temperature, which will lead to a rise in sea level.
2. Melting of glaciers
Global warming has led to accelerated melting of polar glaciers and ice caps. The South Pacific region is home to a large number of glaciers and ice caps, including parts of Antarctica, and the rate of melting of these ice bodies has accelerated significantly in recent years. The melting of ice bodies leads to an increase in the volume of water and its flow into the oceans, which directly contributes to sea level rise. Since greenhouse gas emissions are only one of the causes of global temperature rise, I do not put glacier melting and greenhouse gas emissions in the same category.
3. Ice shelf disintegration
Ice shelves are glacial extensions that extend over the oceans. Global warming has led to the melting and disintegration of ice shelves, which has accelerated the rate of inflow of land-based glaciers into the oceans. The disintegration of ice shelves in the South Pacific region has led to the inflow of more ice into the ocean, which has contributed to the rise in sea level.
According to foreign research: The effects of Antarctic iceberg calving-size distribution in a global climate model, as shown in the figure below, based on the modeling comparison of different glacier formation lengths, we can see that as the glaciers produced by ice shelf disintegration become larger and larger, glacier The impact on the marine environment is also more extensive, extending from simply around the Antarctic to more areas, especially in the South Pacific. This has important implications for the density and distribution of seawater, as well as for sea level rise in the South Pacific. In recent years, with climate change, ice-shelf collapse has accelerated and crevasses have become larger, also contributing to faster sea-level growth in the South Pacific.
II. Geological Tectonics
1. Crustal plate activity
The South Pacific is located in the "Pacific Rim Seismic Zone", one of the most active seismic zones on Earth. Crustal plate activity can lead to changes in the geology of the seafloor, which in turn affects sea level. For example, plate movement may cause fault activity, leading to vertical displacement of the Earth's crust, which in turn changes the seafloor topography, causing sea level to rise or fall in localized areas.
As we can see from the above figure, the South Pacific region is located at the junction of the Indian Ocean plate and the Pacific Ocean plate, and the seafloor topography is very complex. Since the seabed topography is constantly changing, the frequent geological activities in recent years have also had an impact on the sea level in the South Pacific region and even in the world.
2. Volcanic activity
There are many active volcanoes in the South Pacific, some of which are located on the seafloor. Volcanic activity can lead to undersea volcanic eruptions, releasing large amounts of magma and gases into the ocean, affecting the volume and density of seawater, and consequently sea level changes.
As we can see from the graph, the South Pacific has a very high number of volcanoes, one of the highest in the world. However, due to the small number of volcanic eruptions and their limited impact, this has not been a major factor in sea level rise in the South Pacific.
3. Crustal uplift and subsidence
The uplift and subsidence of the Earth's crust is another factor in geological formations. Crustal uplift or subsidence may occur in certain areas under the influence of crustal plate movements and tectonics. If the area of crustal uplift is located near the coastline, the sea level will fall in relative terms, while if the area of crustal subsidence is located near the coastline, the sea level will rise in relative terms. This also has an impact on sea level rise in the South Pacific.
iii. human activities
1. Coastal cities and infrastructure development
Coastal cities and infrastructure development in the South Pacific are usually concentrated near the coastline. With the increase of urban population and economic development, human activities such as land development, land reclamation and marina construction have led to land subsidence along the coastline. This subsidence has led to a rise in relative sea level, exacerbating the effects of rising sea levels.
However, nowadays, the South Pacific has a slow and low economic development, and there are not even a few large-scale coastal cities, so this factor does not have much impact on the sea level in the South Pacific.
2. Groundwater pumping
Groundwater abstraction is an activity carried out to meet agricultural, industrial and urban water needs. Large-scale groundwater pumping can lead to ground compaction and trigger land subsidence, especially in coastal areas. Land subsidence due to groundwater pumping further contributes to relative sea level rise. Since the South Pacific region lacks freshwater resources, their main method of water extraction is from the ground, and large-scale and continuous freshwater extraction further causes land subsidence in the South Pacific region, leading to a rise in sea level and a serious impact on people's lives.
3. Deforestation and wetland destruction
Forests and wetlands are nature's marine moats, capable of absorbing and storing large amounts of water. However, large-scale deforestation and wetland destruction have led to water loss and changes in the hydrological cycle, accelerating the process of sea level rise.
IV. Summary
To summarize, sea level rise in the South Pacific is a comprehensive issue, which is affected by a combination of factors such as global climate change, geological structure and human activities. The process of mitigating sea level rise requires the joint efforts of the international community, including the reduction of greenhouse gas emissions, the protection of forests and wetlands, and the rational planning of coastal cities and infrastructure construction. Only through global cooperation can the challenges posed by sea-level rise in the South Pacific be effectively addressed.
中文参考：
南太平洋海平面上升是一个严重的气候变化问题，影响着无数人的生活。这一问题是由几个复杂因素造成的。在本文中，我将总结分析南太平洋地区海平面上升的三个主要原因，包括全球气候变化、地质构造和人类活动。之后，我将在我的公众网站上发表几篇文章，详细分析这些原因。
I. 全球气候变化
全球气候变化是导致南太平洋海平面上升的最主要原因，根据我的总结，全球气候变化导致南太平洋海平面上升的原因主要有以下三个方面：
1、温室气体排放
二氧化碳（CO2）、甲烷（CH4）和二氧化氮（N2O）等温室气体的排放是造成温室效应的主要原因，它们在大气中积聚，导致地球变暖。
人类活动，尤其是燃烧化石燃料、工业生产和砍伐森林，释放出大量温室气体。这些气体在白天吸收了地球表面的部分辐射，并不断将吸收的热量传递到大气中，导致大气温度升高。根据最简单的热胀冷缩原理，海洋会因温度升高而发生热膨胀，从而导致海平面上升。
2. 冰川融化
全球变暖导致极地冰川和冰盖加速融化。南太平洋地区有大量冰川和冰盖，包括南极洲的部分地区，近年来这些冰体的融化速度明显加快。冰体融化导致水量增加，流入海洋，直接造成海平面上升。由于温室气体排放只是全球气温升高的原因之一，我不把冰川融化和温室气体排放归为一类。
3. 冰架解体
冰架是冰川在海洋上的延伸。全球变暖导致冰架融化和解体，加快了陆地冰川流入海洋的速度。南太平洋地区冰架的解体导致更多的冰流入海洋，从而造成海平面上升。
根据国外的研究： 全球气候模型中南极冰山压裂大小分布的影响，如下图所示，根据不同冰川形成长度的建模对比，我们可以看到，随着冰架解体产生的冰川越来越大，冰川 对海洋环境的影响也越来越广泛，从单纯的南极周边延伸到更多的地区，尤其是南太平洋。这对海水的密度和分布以及南太平洋海平面的上升都有重要影响。近年来，随着气候变化，冰架坍塌加速，裂缝变大，也导致南太平洋海平面上升加快。
II. 地质构造
1. 地壳板块活动
南太平洋位于 "环太平洋地震带"，这是地球上最活跃的地震带之一。地壳板块活动会导致海底地质发生变化，进而影响海平面。例如，板块运动可能引起断层活动，导致地壳垂直位移，进而改变海底地形，造成局部地区海平面上升或下降。
从上图可以看出，南太平洋地区位于印度洋板块和太平洋板块的交界处，海底地形非常复杂。由于海底地形不断变化，近年来频繁的地质活动也对南太平洋地区乃至全球的海平面产生了影响。
2. 火山活动
南太平洋有许多活火山，其中一些就位于海底。火山活动会导致海底火山爆发，向海洋释放大量岩浆和气体，影响海水的体积和密度，从而引起海平面的变化。
从图中我们可以看到，南太平洋的火山数量非常多，是世界上火山数量最多的地区之一。然而，由于火山喷发次数少，影响有限，这并不是南太平洋海平面上升的主要因素。
3. 地壳隆升和下沉
地壳的隆起和下沉是地质构造的另一个因素。在地壳板块运动和构造作用的影响下，某些地区会出现地壳隆起或下沉。如果地壳隆起的区域位于海岸线附近，海平面就会相对下降，而如果地壳下沉的区域位于海岸线附近，海平面就会相对上升。这对南太平洋的海平面上升也有影响。
三、人类活动
1. 沿海城市和基础设施建设
南太平洋的沿海城市和基础设施开发通常集中在海岸线附近。随着城市人口的增加和经济的发展，土地开发、填海造地和码头建设等人类活动导致了沿海岸线的土地下沉。这种沉降导致相对海平面上升，加剧了海平面上升的影响。
但目前南太平洋经济发展缓慢，水平较低，甚至没有几个大规模的沿海城市，因此这一因素对南太平洋海平面的影响不大。
2. 抽取地下水
抽取地下水是为满足农业、工业和城市用水需求而进行的活动。大规模抽取地下水会导致地面板结，引发地面沉降，尤其是在沿海地区。抽取地下水导致的土地沉降进一步加剧了海平面的相对上升。由于南太平洋地区缺乏淡水资源，其主要取水方式是从地下抽取，大规模持续抽取淡水会进一步造成南太平洋地区的土地沉降，导致海平面上升，严重影响人们的生活。
3. 森林砍伐和湿地破坏
森林和湿地是大自然的海上护城河，能够吸收和储存大量的水。然而，大规模的森林砍伐和湿地破坏导致了水的流失和水文循环的变化，加速了海平面上升的进程。
IV. 总结
总之，南太平洋海平面上升是一个综合问题，受到全球气候变化、地质结构和人类 活动等综合因素的影响。减缓海平面上升的进程需要国际社会的共同努力，包括减少温室气体排放、保护森林和湿地、合理规划沿海城市和基础设施建设等。只有通过全球合作，才能有效应对南太平洋海平面上升带来的挑战。
