Satellites are Tracking the Ongoing Sea Level Rise Swamping Pacific Island Nations

The small island nations of the South Pacific are facing the harsh reality of sea level rise. Within 50 years they will be swamped by rising seas linked to climate change. That’s part of a stark forecast from a sea level change science team at NASA and leading universities.

The group used satellites to predict rising ocean levels. According to their data, Pacific nations such as Tuvalu, Kiribati, and Fiji will experience an increased rise in sea levels. That threatens the homes and livelihoods of millions of people.

The Team’s Work

The team that examined the rise of sea levels threatening South Pacific nations is part of an interdisciplinary research group at NASA. Its job is to improve our understanding of sea-level change over time. The members analyzed the South Pacific threat at the request of the affected nations and coordinated with the U.S. State Department. They created high-resolution maps showing which areas of different Pacific Island nations would be vulnerable to high-tide flooding. The maps outline the potential for flooding. In addition, they take into account different greenhouse gas emissions scenarios, ranging from best-case to business-as-usual to worst-case.

One of the islands of Tuvalu. Sea level rise threatens to swamp the islands of this nation within 50 years. Courtesy NASA.

A combination of space-based and ground-based measurements can yield more precise sea level rise projections. That should give an improved understanding of the impacts on countries in the Pacific. Still, it’s one thing to create predictive models and share that data with affected nations. It’s quite another to actually experience the gradual rise of sea levels as the people of the South Pacific islands and other low-lying areas along the world’s coastlines.

“I am living the reality of climate change,” said Grace Malie, a youth leader from Tuvalu who is involved with the Rising Nations Initiative, a United Nations-supported program led by Pacific Island nations to help preserve their statehood and protect the rights and heritage of populations affected by climate change. “Everyone (in Tuvalu) lives by the coast or along the coastline, so everyone gets heavily affected by this.”

How NASA Tracks Sea-level Rise

Researchers from the University of Hawaii, the University of Colorado, and Virginia Tech all took part in the study, which used a new Pacific Islands Flooding Tool for the project. The data they use comes from measurements by satellites, shipboard and airborne instruments, and supercomputer analysis. The result is a more precise assessment of sea levels and their rise and fall over time. Using this data, the science teams found some worrying trends.

The portal to NASA’s Pacific Islands flooding analysis tool to help scientists assess sea level rise in low-lying areas. Courtesy NASA.

“Sea level will continue to rise for centuries, causing more frequent flooding,” said Dr. Nadya Vinogradova Shiffer, who directs ocean physics programs for NASA’s Earth Science Division. “NASA’s new flood tool tells you what the potential increase in flooding frequency and severity look like in the next decades for the coastal communities of the Pacific Island nations.”

What Affects Sea Level?

Sea level rise is based on a number of factors, including melting of glaciers and other ice packs and ocean warming related to pumping greenhouse gases into the atmosphere. Based on the data from NASA satellites, the Pacific Islands most at risk will see at least a 15-cm sea level rise by 2050. That’s nearly an order of magnitude higher than all Pacific Island nations experience now. To give you an idea of how that will affect specific places, Tuvalu currently sees less than five high tide flood days per year. By 2050, residents will experience at least 25 flood days each year. Kiribati will see 65 flood events. The maps produced by the NASA-led team for these and other islands should help these nations plan for future flood mitigation efforts.

“Science and data can help the community of Tuvalu in relaying accurate sea level rise projections,” said Malie. “This will also help with early warning systems, which is something that our country is focusing on at the moment.”

Assessing Sea Level Rise

Not every area in the world experiences the same amount of flooding. Local conditions and coastlines contribute to area-specific floods. The impact that 15 centimeters of sea level rise will have varies from country to country. Some regions will see nuisance flooding several times a year in flat or low-lying areas. Others face inundation for longer periods with higher amounts of water.

“We’re always focused on the differences in sea level rise from one region to another, but in the Pacific, the numbers are surprisingly consistent,” said Ben Hamlington, a sea level researcher at NASA’s Jet Propulsion Laboratory in Southern California and the agency’s sea level change science team lead.

The impacts of sea level rise will vary from place to place and depend on topography, shapes of coastlines, and other factors. Better predictive tools will help scientists understand where sea levels will rise the most and share that information with affected populations. Researchers would like to combine satellite data on ocean levels with ground-based measurements of sea levels at specific points, as well as with better land elevation information. “But there’s a real lack of on-the-ground data in these countries,” said Hamlington.

Real-world Experience

The combination of space-based and ground-based measurements can yield more precise sea level rise projections and an improved understanding of the impacts on countries in the Pacific. Still, it’s one thing to create predictive models and share that data with affected nations. It’s quite another to actually experience the gradual rise of sea levels as the people of the South Pacific islands and other low-lying areas along the world’s coastlines.

People in these regions experience different types of threats from the oceans. Flooding can occur when the ocean inundates the land during tropical storms, typhoons, and hurricanes. It can also happen during exceptionally high tides, called king tides.

An example of sunny day king tide flooding submerging street infrastructure outside the City of Miami Fire Station 13. Sea level rise contributes to increased incidences of such flooding. Credit: Mike Sukop/NOAA.

Another avenue for flooding is saltwater intrusion into underground areas. That pushes the water table to the surface. “There are points on the island where we will see seawater bubbling from beneath the surface and heavily flooding the area,” Malie added.

Places like Tuvalu will benefit from better tools to predict sea level rise. It’s not just a matter of preventing flooding, but one of a nation’s survival now and over the next few decades. “The future of the young people of Tuvalu is already at stake,” said Malie. “Climate change is more than an environmental crisis. It is about justice, survival for nations like Tuvalu, and global responsibility.”

For More Information

NASA Analysis Shows Irreversible Sea Level Rise for Pacific Islands
Sea Level Change
Pacific Islands Flooding Tool

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