Sea Level Rise

National Geographic

Ocean levels are getting higher. Why is this happening, and what can we do to stem the tide?

Families in Kiribati, especially those new to the island nation, are often forced to live in marginal areas, where flooding from high tides is increasing. Photograph by Kennedy Warne

Core samples, tide gauge readings, and, most recently, satellite measurements tell us that over the past century, the Global Mean Sea Level (GMSL) has risen by 4 to 8 inches (10 to 20 centimeters). However, the annual rate of rise over the past 20 years has been 0.13 inches (3.2 millimeters) a year, roughly twice the average speed of the preceding 80 years. Over the past century, the burning of fossil fuels and other human and natural activities has released enormous amounts of heat-trapping gases into the atmosphere. These emissions have caused the Earth's surface temperature to rise, and the oceans absorb about 80 percent of this additional heat. The rise in sea levels is linked to three primary factors, all induced by this ongoing global climate change:

• Thermal Expansion:
  When water heats up, it expands. About half of the past century's rise in sea level is attributable to warmer oceans simply occupying more space.
• Melting Glaciers and Polar Ice Caps:
  Large ice formations, like glaciers and the polar ice caps, naturally melt back a bit each summer. In the winter, snows, primarily from evaporated seawater, are generally sufficient to balance out the melting. Recently, though, persistently higher temperatures caused by global warming have led to greater-than-average summer melting as well as diminished snowfall due to later winters and earlier springs. This imbalance results in a significant net gain in the ratio of runoff to ocean evaporation, causing sea levels to rise.
• Ice Loss from Greenland and West Antarctica:
  As with the glaciers and ice caps, increased heat is causing the massive ice sheets that cover Greenland and Antarctica to melt at an accelerated pace. Scientists also believe meltwater from above and seawater from below is seeping beneath Greenland's and West Antarctica's ice sheets, effectively lubricating ice streams and causing them to move more quickly into the sea. Higher sea temperatures are causing the massive ice shelves that extend out from Antarctica to melt from below, weaken, and break off.

Superstorm Sandy narrowed New Jersey's beaches by more than 30 feet on average. At Seaside Heights it swept away the pier under the roller coaster. Photograph by Stephen Wilkes

Consequences
When sea levels rise rapidly, as they have been doing, even a small increase can have devastating effects on coastal habitats. As seawater reaches farther inland, it can cause destructive erosion, wetland flooding, aquifer and agricultural soil contamination, and lost habitat for fish, birds, and plants.
When large storms hit land, higher sea levels mean bigger, more powerful storm surges that can strip away everything in their path. In addition, hundreds of millions of people live in areas that will become increasingly vulnerable to flooding. Higher sea levels would force them to abandon their homes and relocate. Low-lying islands could be submerged completely.

Meltwater gushes from an ice cap on the island of Nordaustlandet, in Norway's Svalbard archipelago. Photograph by Paul Nicklen, National Geographic Creative

How High Will It Go?
Most predictions say the warming of the planet will continue and is likely to accelerate. Oceans will likely continue to rise as well, but predicting the degree to which they will rise is an inexact science. The Intergovernmental Panel on Climate Change says we can expect the oceans to rise between 11 and 38 inches (28 to 98 centimeters) by 2100, enough to swamp many of the cities along the U.S. East Coast. More dire estimates, including a complete meltdown of the Greenland ice sheet, place sea level rise to 23 feet (7 meters), enough to submerge London.

Montana A deluge falls from the core of a thunderstorm near Glasgow in July 2010. "I felt like if you could stand in the middle and look up, you'd see straight into the heavens," says photographer Sean Heavey. Panorama composed of four images; Sean R. Heavey, Barcroft Media/Landov

Links

• Rising Seas
• Air Pollution
• The Big Thaw
• Weather Gone Wild
• Oceans Will Rise Much More Than Predicted, NASA Says

Climate Change To Shift Global Pattern Of Mild Weather

National Oceanic and Atmospheric Administration

New research shows the global average of mild weather days will drop, with dramatic declines for some, increases for others

As scientists work to predict how climate change may affect hurricanes, droughts, floods, blizzards and other severe weather, there’s one area that’s been overlooked: mild weather. But no more.

NOAA and Princeton University scientists have produced the first global analysis of how climate change may affect the frequency and location of mild weather – days that are perfect for an outdoor wedding, baseball, fishing, boating, hiking or a picnic. Scientists defined “mild” weather as temperatures between 64 and 86 degrees F, with less than a half inch of rain and dew points below 68 degrees F, indicative of low humidity.

Knowing the general pattern for mild weather over the next decades is also economically valuable to a wide range of businesses and industries. Travel, tourism, construction, transportation, agriculture, and outdoor recreation all benefit from factoring weather patterns into their plans.

Tropics to lose milder days
The new research, published in the journal Climatic Change, projects that globally the number of mild days will decrease by 10, or 13 percent, by the end of the century because of climate warming from the buildup of human-caused greenhouse gasses in the atmosphere. The current global average of 74 mild days a year will drop by four days by 2035 and 10 days by 2081 to 2100. But this global average decrease masks more dramatic decreases in store for some areas and increases in mild days in other regions.

“Extreme weather is difficult to relate to because it may happen only once in your lifetime,” said first author Karin van der Wiel, a Princeton postdoctoral researcher at NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL) located on the university’s Forrestal Campus. “We took a different approach here and studied a positive meteorological concept, weather that occurs regularly, and that’s easier to relate to.”  

Scientists predict the largest decreases in mild weather will happen in tropical regions because of rising heat and humidity. The hardest-hit areas are expected to be in Africa, Asia and Latin America, where some regions could see 15 to 50 fewer days of mild weather a year by the end of the century. These are also areas where NOAA and partner research shows economic damages due to climate change. The loss of mild weather days, especially during summer, when they can serve to break up extended heatwaves, also could significantly affect public health.

Parts of U.S., Canada, northern Europe to gain milder days
People living in the mid-latitudes, which include much of the United States, as well as many mountainous areas around the world, will gain mild weather days on average, the new study found. The biggest winners will include communities along the border with Canada in the Northeast, Midwest and Northwest, as well as many parts of Canada.

Other areas projected to gain as much as 10 to 15 days more annually of mild weather by the end of the 21st century include parts of England and northern Europe, and Patagonia in extreme southern South America. In some of these areas, mild weather will drop during increasingly hot and humid summers but become more plentiful in fall, winter and spring as winters warm and the shoulder seasons last longer.

This map shows the change in the annual number of mild days across the globe from the period of 1986-2005 to the period from 2081-2100. Areas of blue are expected to experience an increase in mild days while areas of brown are expected to see a decline in those days. (Van der Wiel/ NOAA/ Princeton)

“We believe improving the public understanding of how climate change will affect something as important as mild weather is an area ripe for more research and more focused studies,” said Sarah Kapnick, a physical scientist at NOAA’s GFDL and co-author. “Predicting changes in mild weather is not only important to business and industry, but can also contribute to research on the future of physical and mental health, leisure and urban planning.”

Scientists used high-resolution climate models to investigate the changing patterns of mild weather globally by examining the effect over time of increased warming from the buildup of greenhouse gas emissions in the atmosphere. The work was made possible by decades of Earth system and model development at NOAA’s GFDL and by improvements made to NOAA’s research supercomputing capability, including access to two high performance supercomputers, Gaea and Theia, named after figures in Greek mythology.

Links

• Shifting patterns of mild weather in response to projected radiative forcing
• A top-down approach to projecting market impacts of climate change
• Research to measure cost of climate change, improve prediction of severe weather
• Playing hide and seek with El Niño
• El Niño/Southern Oscillation and greenhouse warming

World's First Custom-Built Floating City To Rise Off French Polynesian Waters

ABC News - Stephanie Boltje

A floating future - The Seasteading Institute describes its concept as permanent, innovative communities floating at sea. (The Seasteading Institute)

Key points The Seasteading Institute has been searching for a location for five years The French Polynesian pilot project will be built in sheltered waters Floating cities could be a solution to rising sea levels around the Pacific

The world's first floating city could be constructed off the waters of French Polynesia after the Government signed an agreement with a United States company in San Francisco at the weekend.
The Seasteading Institute has been researching the potential for what it describes as permanent, innovative communities floating at sea for the past five years.
After signing a memorandum of understanding with the French Polynesian Government, it is hopeful construction can start by 2019.
The institute's executive director, Randolph Hencken, told Pacific Beat finding a host nation was a significant milestone.
He said the next steps involved economic and environmental impact studies as well as legal investigations to figure out the special governing framework the institute believes is crucial to the ongoing success of its floating communities.

French Polynesia's ministerial representative Jean-Christophe Bouissou (R) signs off on the floating island project with Randolph Hencken from The Seasteading Institute. (Presidence de la Polynesie francaise.)

The Seasteading Institute was founded by Wayne Gramlich and Patri Friedman in 2008 to establish autonomous, mobile communities on seaborne platforms operating in international waters.
The French Polynesian prototype will not be in international waters but the institute still hopes its vision can be incorporated.
Mr Hencken said the detail of political autonomy needed to be negotiated and considered under the sovereignty of French Polynesia and France, of which French Polynesia is a territory.
"What we're interested in is societal choice and having a location where we can try things that haven't been tried before," Mr Hencken said.
"I don't think it will be that dramatically radical in the first renditions.

"But I imagine it has the opportunity to have different ways of voting for how things are run off the island instead of using the same systems that our great great-grandparents have given us that seem to have failed in so many first-world nations."

Mr Hencken said a former minister from the Government in Papeete approached his company last year and after a site inspection, the azure seas of the Pacific appealed for several reasons.
"We were looking for sheltered waters — we don't want to be out in the open ocean — it's technologically possible but economically outrageous to afford," he said.
"If we can be behind a reef break, then we can design floating platforms that are sufficient for those waters at an affordable cost."
Other attractions included fewer cyclones, a major airport in Tahiti and other aspects of modern life, like restaurants.
"We don't have to start from scratch as this is a pilot project," he said.
"They also have very stable institutions so we're able to work with a government that wants us there, that we have respect for and they have respect for us."
One of the challenges in the lead-up will be to prove the economic benefit to the Government.
"We are confident there will be both a direct and an indirect benefit for them economically," Mr Hencken said.
"They are a tourist-based economy and they're excited to bring us in because we are a technology-based idea.
"The first islands are going to be a pilot project and there will just be many dozens [of people] to get started with and then … we grow and are more successful, we will hopefully see hundreds and thousands of people living there.

"What excites me about the project is a location where people are going to create a community based on interests on floating islands rather than have a community because they happen to be born there and this is their ethnicity."

Beverley O'Connor speaks to The Seasteading Institute's Ashley Blake (The World)

The agreement with the French Polynesian Government is for the studies to be completed this year and incorporated into draft legislation. If passed by the end of 2018, construction can start in the next year.

A solution to the Pacific's rising sea levels
The Seasteading Institute believes their vision for "sustainable, floating islands and innovative islands" will prove to be part of the solution to rising sea levels.
"So much of the world — places like Kiribati and many of the islands of French Polynesia — are threatened by rising sea levels," Mr Hencken said.
"We are planning to spin off a new industry of floating islands that will allow people to stay tethered to their sovereignty as opposed to having to flee to other countries.
"That's certainly why the Tahitians are interested in us. They want the environmental resiliency as well as the economic opportunities."

Links

• Floating farms may boost Singapore's food security
• US group plans floating cities with 'start-up governments'
• A plan to create cities which float on the ocean
• The Seasteading Institute