The U.S. East Coast was hit with hurricanelike floodingRecent weeks have seen Georgia and South Carolina receiving the latest round. High tides are part of the problem, but there’s another risk that has been slowly creeping up: sea level rise.
Since 1880, average global sea levels have risen by more than8 inches (23 cm) and the rate has been acceleratingClimate change.
Scientists predict that scientists will estimate how effective countries are in reducing their greenhouse gas emissions over the next few years. global sea levels could riseAn additional 2 feet will be added by the end this century. In some areas – including Charleston, South Carolina, where a storm and high tide on Nov. 5, 2021, sent water levels about 8 feet above normal – sinking landThis is making the impact worse.
I’m a geoscientist who studies sea level riseClimate change and its effects. Here’s a quick explanation of two main ways climate change is affecting oceans levels and their threat to the world’s coasts.
Ocean thermal expansion
Climate change is a result of human activities and fossil fuel use. It is causing global average surface temperatures to rise. This is causing the oceans to absorb more heat now than before the industrial era. This is causing ocean thermal expansion.
Thermal expansion simply means sea water molecules moving closer together as the ocean heats. The more space they take up, the farther apart the molecules will be.
This expansion causes the ocean to rise higher onto land.
Over the past several decades, about 40%Thermal expansion caused the rise in global sea levels. The ocean, which covers just over two-thirds of the Earth’s surface, has been absorbing and storing more than 90%The greenhouse gas emissions are adding heat to the climate system.
Melting land ice
The other major factor in rising sea levels is that the increase in average global temperatures is melting land ice – glaciers and polar ice sheets – at a faster rate than natural systems can replace it.
Land ice melts and the meltwater eventually flows into oceans, increasing ocean volume and adding water to it.
In the last several decades, around 50% of global sea level risewas caused by land ice melting.
The polar ice sheets of Greenland and Antarctica contain enough frozen water that, if they were to melt completely, it would raise global sea level by as much as a third. 200 feet, or 60-70 meters – about the height of the Statue of Liberty.
Sea ice is also melting due to climate change. However, because this ice already floats at the ocean’s surface and displaces a certain amount of liquid water below, this melting does not contribute to sea level rise.
While the surface height of the oceanAlthough global warming is increasing, the impacts are not the same for all coastal regions. Some places may see a rise that is several times faster than others. This difference is caused by an area’s unique local conditions – such as shifts in ocean circulation and the uplift or subsidence of the land.
Even if emissions are stabilized, the risks will continue to rise.
Nearly 4 out 10 Americans live near the coast, and millions of people already deal with it. coastal floodingHigh tides and hurricanes can cause significant damage to coastal infrastructure and ecosystems, as well as homes and buildings. In late October, flooding occurred in the Chesapeake Bay region due to high tides. Miami now deals with high-tide floodingMultiple times a year.
Researchers around the globe have calculated that sea level could rise this century, according to researchers. trillions of dollars in damage. Some low-lying island countries, including the Maldives and Kiribati in Pacific Ocean, are already facing rising seas, which is forcing them to make tough decisions about whether to build expensive ocean protections that won’t last long or abandon their islands.
The U.N. climate conference in Glasgow will bring together officials from around the globe with the goal of reducing global greenhouse gas emissions so that global temperatures don’t rise too high.
Even with a reduction in emissions, sea levels will continue to rise for centuries. The massive ice sheets of Greenland and Antarctica will continue their melting and will take a long while to reach a new equilibrium. The latest report from the Intergovernmental Panel on Climate Change showsThe climate system’s excess heat has locked in current rates of thermal expansion, land ice melting for at least the next few years.