Rising Seas, Sinking Cities: The Global Crisis Unfolding Right Before Our Eyes​

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Billions in flood damage, sinking infrastructure, and displaced families as climate change drives the oceans higher.

 

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​Storm clouds gather over Port Dickson Beach, deterring tourists and keeping many from swimming. 

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From Jakarta to New York City, the world’s coastlines are changing right before our eyes. Sea level rise is no longer a fairytale, it is a crisis that is already happening in plain sight, noticed by people, but not taken seriously enough by many worldwide leaders. It threatens to reshape economies, erase cultural landmarks and displace entire nations. Scientists say this change is happening faster than at any time in recorded history. The choices we make in the upcoming decades will determine whether millions of souls can adapt safely or struggle to survive against the rising waters.

The reasons involve two main processes: thermal expansion and melting ice. Warmer water expands and takes up more space compared to room temperature or cold water. This pales in comparison to how much glaciers and polar ice sheets continue to melt and release water into the oceans, causing the sea levels to rise significantly over the years. Together, all these factors are pushing sea levels to rise faster than ever seen before in over 2,500 years. And these factors aren’t just a theory, the rising seas are already being measured in real time.

The rate that the sea level is rising is quickening as we experience warmer years. In the early 20th century, global sea levels rose about 1.4 millimeters per year. By the 1990s, that figure had increased to around 2.1 mm annually. According to NASA and European satellites, the rate doubled again, reaching about 4.5 mm per year in 2023, much faster than ever predicted.

But those global averages hide an uneven reality, some coasts are drowning much faster than others. For example, some coastlines of the United Kingdom have risen by 13.4 centimeters since 1993 compared to a global average of 10.6 cm. In the United States, land sinking makes cities like New Orleans and Miami more susceptible towards the rising water levels. In Asia, sea levels are rising about 10 percent faster than the global average. This year, nearly one billion people around the world will face the effects of rising sea levels. 

Even small increases can have huge impacts. A 20 centimeter rise in sea level by 2050 could lead to hundreds of billions of dollars in annual flood damage in major cities. In Tamil Nadu, India, projections warn of up to 78 centimeters of rise by 2100 if emissions stay high. Chennai and other coastal cities are already experiencing more severe floods prompting officials to consider making new infrastructure to try to slow down the threat. 

But not all dangers roar in like a storm, some creep in quietly on calm, sunny days, when there is not a cloud in the sky. For example, the phenomena “sunny day floods” is when high tides overwhelm the streets without any rain. Sunny day floods are also becoming more common in cities that are in coastal regions. Saltwater would intrude into farmlands and freshwater supplies, causing them to become contaminated. Crops would die from excess salt, while aquifers become so brackish that drinking from them would be no different than drinking straight from the ocean.

The Intergovernmental Panel on Climate Change (IPCC) projects that if global warming is kept at 1.5 °C, sea levels will rise between 26 and 77 centimeters by 2100. At 2 °C, the rise could be closer to half a meter. If global warming exceeds 2.5 °C, scientists warn of long-term increases of up to 5 to 6 meters. The difference between 1.5 °C versus 2.5 °C could decide whether millions of people can stay in their homes or be forced to migrate.

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Meeting this challenge requires both reducing emissions and adapting. Cutting greenhouse gas emissions is important to slow the causes of sea level rise. But adaptation through infrastructure, natural defenses, and community planning is also required as we move through this phase of climate instability.

Some cities are building seawalls, flood gates and storm barriers, while others are restoring wetlands and mangroves to absorb storm surges. Seawalls work as a wall between the ocean and the coastline. Whenever storms hit, and the waves become stronger, they would hit the seawalls and not penetrate further. Flood gates and storm barriers are like large movable “dams” that stop water from breaching into the city during high tides or storms. For example, the Modulo Sperimentale Elettromeccanico (MOSE) is a system of mobile, submerged flood gates that are designed to protect Venice, Italy from flooding caused by high tides. MOSE blocks rising sea levels and storm surges from the Adriatic Sea, preventing floods and infrastructure damage in Venice. The MOSE costs €6 billion to construct.

 In extreme cases, “managed retreat” may become necessary. Managed retreat means moving populations and infrastructure away from the most vulnerable coastlines in the events of a flood. This is done to save lives and infrastructure from damage.
In conclusion, worldwide sea level rise is no longer a distant threat. The question is not whether sea levels will keep rising, but how quickly they will do so and how humanity will adapt to the ever impending threat. Every fraction of a degree of warming avoided and every centimeter of sea level rise prevented will shape the future for billions of people living near the world’s coastlines.
 

 

References
 

1. European Environment Agency. (2025). Global and European sea level rise. Retrieved September 21, 2025, from https://www.eea.europa.eu/en/analysis/indicators/global-and-european-sea-level-rise

2. Hamlington, B. D., et al. (2024). The rate of global mean sea level rise over the past three decades has more than doubled. Retrieved September 21, 2025, from https://www.nature.com/articles/s43247-024-01761-5

3. Hamlington, B. D., et al. (2025). Rate of sea level rise doubled over 30 years, new study shows. Retrieved September 21, 2025, from https://www.sealevel.nasa.gov/news/280/rate-of-sea-level-rise-doubled-over-30-years-new-study-shows

4. Intergovernmental Panel on Climate Change (IPCC). (2018). Global warming of 1.5°C – Special report. Retrieved September 21, 2025, from https://www.ipcc.ch/site/assets/uploads/sites/2/2018/12/ST1.5_OCE_LR.pdf

5. NASA. (2024). NASA analysis sees spike in 2023 global sea level due to El Niño. Retrieved September 21, 2025, from https://www.sealevel.nasa.gov/news/270/nasa-analysis-sees-spike-in-2023-global-sea-level-due-to-el-nino

6. NASA. (n.d.). Sea level – Vital signs of the planet. Retrieved September 21, 2025, from       https://www.climate.nasa.gov/vital-signs/sea-level

7. Science & Development Network. (2022). Asia’s coastal cities ‘sinking faster than sea level-rise’. Retrieved September 21, 2025, from https://www.preventionweb.net/news/asias-coastal-cities-sinking-faster-sea-level-rise

8. Tara, R. (2023, April 14). Venice’s tide barrier has already cost €6 billion—will it work? Engineering.com. Retrieved September 21, 2025, from https://www.engineering.com/venices-tide-barrier-has-already-cost-6-billion-euros-will-it-work/

9. U.S. Climate Resilience Toolkit. (2022). Sea level rise technical report – Observed global sea level rise 1920–2020. Retrieved September 21, 2025, from https://www.toolkit.climate.gov/sea-level-rise

10. U.S. Environmental Protection Agency. (n.d.). Climate change indicators: Sea level. Retrieved September 21, 2025, from https://www.epa.gov/climate-indicators/climate-change-indicators-sea-level

11. World Meteorological Organization (WMO). (2025). Rising temperatures and extreme weather hit Asia hard. Retrieved September 21, 2025, from https://www.wmo.int/news/media-centre/rising-temperatures-and-extreme-weather-hit-asia-hard

Muhammad Adam Arif Bin Moggon @ Jauhari & Hud Rayyan Bin Zul Ilham

Malay College Kuala Kangsar (MCKK)