What causes sea level rise? A US report warns that sea level rise will be 1-foot within three decades, with more frequent flooding.

The sea levels are rising and will pose a flood risk to large areas of the Gulf and Atlantic coasts in the coming decades.

A new report by scientists from the National Oceanic and Atmospheric Administration warns the U.S. to be more careful. Prepare for 10-12 inchesrelative sea level increase on average over the next 30 years. Global warming and sinking lands are both contributing to the rise. Given the amount of greenhouse gases released so far, it is unlikely that the country can avoid it.

This much sea level rise can lead to cities like MiamiBy midcentury, areas that experience nuisance flooding due to high tides will see more severe floods. According to the report, moderate coastal flooding is expected to occur 10 times more often by 2050. High tides are likely to cause flooding in the coastal infrastructure and disrupt supply chains, as well as streets, if there aren’t significant adaptations.

The oceans will be higher. Bring seawater further inland. Depending on the world’s reductions in greenhouse gas emissions, sea level will rise by an average of 2 feet per century.

As a geoscientist, I study sea level riseClimate change and its effects. Here’s a quick explanation of two main ways global warming is affecting ocean levels and their threat to the coasts.

Ocean thermal expansion

The atmosphere traps energy that would otherwise escape into space as a result of greenhouse gases resulting from human activities and fossil fuel use. This energy causes global average surface temperatures to rise, particularly in the upper layers of oceans.

The ocean heats up and causes thermal expansion. Sea water molecules move closer together due to heat, taking up more space. The ocean rises higher and floods more land.

Over the past few decades, About 40%Thermal expansion is responsible for the rise in global sea levels. The ocean, which covers about 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.

Ice melting from land

Melting land ice is another major factor in rising sea level. The rate at which mountain glaciers and polar Ice Sheets are melting faster than natural systems can replace is alarming.

When land ice melts into meltwater, it eventually flows into the ocean. This adds new water to the ocean and increases the total ocean mass.
About 50%The past several decades of land ice melting caused the global sea level rise.

Currently, the Greenland and Antarctica polar ice sheet hold enough frozen waters to raise the global sea-level if they melt completely. Up to 200 feet, or 60-70 meters – about the height of the Statue of Liberty.

Climate change is also melting sea ice. 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.

Even after emissions stabilize, the risk of an explosion will continue to increase

While the Surface height of the oceanAlthough global temperature rises as the planet heats, the impact on each coastal area is different. Some places may experience a rise that is several times faster due to unique local conditions like shifts in ocean circulation, or subsidence.

For example, the U.S. East Coast & Gulf Coast are both facing Risks that exceed the averageAccording to the report, Hawaii and the West Coast are projected to be lower that the average.

Nearly 4 out 10 Americans live near the coast, and a large portion of the U.S. economic activity is also there.

Even if greenhouse gas emissions fall, sea level will continue rising for centuries. This is because the huge ice sheets in Greenland & Antarctica will continue melting and it will take a long time to find a new equilibrium. A 2021 report of the Intergovernmental Panel on Climate ChangeThe excess heat already present in the climate system has locked into the current rates of thermal extension and land ice melting for at least the next few years.