WORDS TO KNOW
verb. to cover with or plunge into water or another liquid
noun. the usual weather in a place
Venice, Italy, is often called the “City of Water.” Instead of using cars and roads, people there travel in boats through a maze of canals.
Residents of Venice are used to being surrounded by water. But serious flooding is putting their city at risk. For centuries, Venice has flooded in the fall and winter. In recent years, however, the floods have gotten worse. Last November, about 70 percent of the city was underwater.
Rising seas are only part of the problem—Venice is also sinking! The city was built on soft soil about 1,500 years ago. Over time, the city has been sinking under the pressure of its own weight.
The Italian government is working to save Venice. By the end of 2014, it plans to finish building a system of huge floodgates to help hold back rising waters.
Eight inches. That’s how much sea levels around the world have risen, on average, in the past century. Eight inches may not seem like a lot. But scientists say this increase is having a big impact worldwide.
People along the East Coast of the U.S. felt the effects of rising sea levels last fall. That’s when Hurricane Sandy hit. Severe flooding from the storm swallowed thousands of homes and businesses along the coasts of New York, New Jersey, and Connecticut.
This disaster may be a sign of things to come. Many scientists say flooding from big storms could become more common as sea levels keep rising.
“Water levels that might only be reached once in a century may now be reached once a decade,” says scientist Peter Howd.
Rising seas could also change how the world looks in the future. Some island nations may one day be wiped off the map. The Maldives is an island chain in the Indian Ocean. It’s one of several countries that could vanish beneath the waves. Its leaders are discussing a plan to abandon the islands. Nearly 400,000 people would be moved to other nations.
Island nations aren’t the only ones at risk. Scientists predict that sea levels could rise by as much as three feet by the end of the century. As a result, water could one day submerge coastal cities like Venice, Italy, and Miami, Florida.
A HOTTER PLANET
Scientists say the rise in sea levels is mainly due to the warming of the planet. Over the past 150 years, Earth’s average temperature has climbed by about 1.4 degrees Fahrenheit. This slow rise in temperature is known as global warming.
Most scientists who study Earth’s climate say that human activity is causing the warm-up. People use fossil fuels to power their homes and cars. Fossil fuels include coal, oil, and natural gas. Burning these fuels releases gases, such as carbon dioxide. These gases trap heat in Earth’s atmosphere.
A RISING CONCERN
How does a warmer planet affect sea levels? First, higher temperatures are causing huge ice sheets and glaciers in Greenland and Antarctica to melt at record rates. The melting ice flows into the seas, causing them to rise.
Second, as the planet warms, so do the seas. When water heats up, it expands, or takes up more space. This causes sea levels to rise.
Though sea levels are rising, climate scientists say people in coastal areas shouldn’t live in fear. Instead, scientists say, cities at risk should plan ahead.
Some coastal cities have been preparing for years. For example, New Orleans, Louisiana, is protected by a system of levees. These human-made barriers are designed to hold back rising waters. Experts say careful planning will make a big difference.
“There are things we can do well ahead of time to make ourselves safer,” says Howd. “We want to start worrying about it now so that by the time [today’s kids] have grandchildren, we’ll be ready.”
Photo credit Patrick McFall