A new study published May 20, 2019 reveals that global sea level rise could increase more than 6 feet (2 meters) by 2100 if greenhouse gas emissions go unchecked.

The study says that sea levels may rise much faster than previously estimated. The United Nations climate panel’s last major report in 2013 predicted that sea levels could rise between 20.4-38.5 inches by 2100 at the current trajectory, but many experts saw those findings as conservative.

To try to get a clearer picture, the new report’s authors asked 22 ice sheet experts to estimate how the Greenland and Antarctic ice sheets might respond to future climate change, using newly advanced regional- and continental-scale, process-based models.

The international researchers found that in the worst-case scenario, under which global temperatures increase by 9 degrees Fahrenheit by 2100, sea levels could rise by more than 6.6 feet in the same period – double the upper limit outlined by the United Nations climate panel.

Such a situation would be catastrophic, the authors of the study warn.

“There are roughly 240 million people in the world who would be flooded if we had 7.8 feet of sea level rise,” says Bob Kopp, a climate and sea level scientist with Rutgers University in New Jersey and a co-author of the study.

The Impacts of Sea Level Rise

The sea level phenomenon, which is an effect of climate change, can have the following impacts:

• Displacement of thousands of people
• Millions of acres of lands destroyed
• Billions of dollars in losses
• Saltwater intrusion into surface waters and groundwater
• Increased coastal erosion
• Potential loss of life
• Increased loss of property and coastal habitats
• Loss of non-monetary cultural resources and values
• Impacts on agriculture & aquaculture via decline in soil & water quality
• Loss of tourism, recreation, and transportation functions
• Potential loss of basic services such as Internet access, due to underwater communications infrastructure

Bearing in mind that many major U.S. cities were established along waterways, effects in these areas would indeed be catastrophic, transformative, and overwhelmingly negative.

Solutions

A growing number of cities are stepping up to the challenge of sea-level rise. Most of them literally have no choice.

Alongside mitigating their carbon footprints through reducing emissions, there are basically three ways that states and cities are taking action.

1) they are fielding hard engineering projects like sea walls, surge barriers, water pumps and overflow chambers to keep water out.

2) they are adopting environmental approaches involving land recovery and the restoration of mangroves and wetlands to help cities cope with floodwater inundation.

3) involves people-oriented measures including urban design, building resilience and retreating after all other options have been exhausted.

Summary

Seas will most certainly rise by the end of the century, threatening major cities and the livelihoods of millions of people, but the extent of rise depends on governments stepping up to set goals and policies that limit warming.

If the global carbon emissions are curtailed within the limits which were agreed under the Paris Agreement on climate change and temperature rise are kept below 3.6 degrees Fahrenheit, the best case scenario in terms of sea level would be an increase of 2.3-foot rise by 2100.

For more information, check out these fantastic articles and resources:

Sea Level Rise from Wikipedia

Sea Level Rise, Explained from National Geographic

Is Sea Level Rising? from the National Ocean Service

Global Sea Levels Could Rise by Much More from TIME

Sea Level Rise Will Flood Hundreds of Cities in the Near Future from National Geographic

8 World Cities That Could Be Underwater as Oceans Rise from EcoWatch

The World’s Coastal Cities Are Going Under. Here’s How Some Are Fighting Back from World Economic Forum

See these resources for infographics and interactive maps:

5 Major Cities Threatened by Climate Change and Sea Level Rise from TheCityFix

The Urban Response to Sea Level Rise from C40 Cities

States At Risk

If you’re interested in learning more about this phenomenon and ways that you can design infrastructure with disaster relief measures in mind, consider our LEED Green Associate training. Though sea level is not the core focus of LEED, the LEED Rating System offers many building strategy ideas to help improve the quality of our buildings and communities.