Lesson 3 Towards a Greener Tomorrow
Rising Seas, Sinking Cities
Global warming has been progressing much faster than scientists originally predicted, and warming temperatures are causing sea levels to rise at a faster rate than ever recorded around the world.
Rising sea levels have already had a big impact in many places, especially in low-lying countries in the South Pacific.
For example, scientists predict that the Pacific island nation of Kiribati will have disappeared under rising sea levels by the end of this century.
This is a problem not just for the South Pacific countries.
Coastal and low-lying areas worldwide are at risk of disappearing from the world map before the 21st century ends.
What's Causing Sea Levels to Rise?
Global warming is causing global sea levels to rise in two ways.
The first factor is the melting of land ice — glaciers and ice sheets.
The enormous bodies of ice cover huge land areas like Greenland and Antarctica, and they hold large amounts of fresh water.
As they melt, the water flows into the ocean.
This causes sea levels to rise.
The second factor is the expansion of water.
When water gets warmer, it naturally expands, and this includes the water in the oceans.
Since the oceans absorb more than 90% of the excess heat trapped by greenhouse gases in the atmosphere, they continuously warm up and accordingly seawater expands.
This increased volume of water occupies more space in the oceans, which causes a rise in sea level.
This process occurs slowly and steadily, and expanding water is estimated to account for about 30% of the sea level rise observed in the past century.
How High Will Sea Levels Rise?
Over the period 1901–2018, sea levels rose by 0.2m.
Sea levels could potentially rise between about 0.38m and 0.77m higher by 2100, depending on the different levels of greenhouse gas emissions.
If the current trend continues, billions of people are expected to be affected by global sea level rise by 2100.
Why Do Sea Levels Matter?
When sea levels rise, there will likely be more frequent and serious flooding along the coasts.
This can cause significant damage in coastal and low-lying regions.
Some villages or even whole cities could end up under water.
This means that millions of people could lose their homes, jobs, and connections to their communities.
Industries such as tourism and fishing may also suffer due to the loss of coastal areas.
Rising sea levels are a concern not just for coastal areas.
Stronger and more dangerous storms can form when the sea levels are higher.
They move more slowly and drop more rain, and thus can cause more destruction to not only coastal regions but also to the areas farther from the coast.
Moreover, higher sea levels can also make salt water go into sources of fresh water.
This salted water will be unsuitable for drinking or growing crops.
The flooding of coastal areas also harms the variety of plants and animals there, as many species can't survive in deeper water or saltier conditions.
What Can We Do?
Sea level rise is a reality we have to face.
What can we do to reduce the damage and prepare for what comes?
Various approaches have been proposed worldwide and put into action to address rising sea levels.
These include building sea walls and better drainage systems to prevent flooding.
Another solution is to raise buildings above flood level or use structures that can float on water.
Preserving and protecting wetlands and mangroves can also reduce the risk of flooding since they absorb water during heavy rains or storms.
As individuals, we can also play a part in dealing with sea level rise by reducing our carbon footprint.
Such efforts may include walking, biking, and using public transportation.
Using energy-efficient electronic devices can also be part of such efforts.
Supporting organizations that work to protect the ocean environments is another way we can make a difference.
Furthermore, many people are still unaware of the risks of sea level rise.
One of the most effective and efficient steps we can take is to raise awareness about the risks.
By raising awareness, we can help others join the fight against global warming.
It's time to raise our voices, not our sea levels.
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