Satellites: Sea Level Rise Accelerating

February 14, 2018

foxsealevel

I read it on Fox, so it must be true.

No, really.  Well vetted AP Story made it verbatim onto the Fox News site.
Significant trend I’ve been tracking – truth about climate leaking into Fox News reports – spotty so far, but clear upward curve, kind of like creeping tidal flooding.

I’ll be interviewing the study author soon to find out more.

AP via Fox:

Melting ice sheets in Greenland and Antarctica are speeding up the already fast pace of sea level rise, new satellite research shows.

At the current rate, the world’s oceans on average will be at least 2 feet (61 centimeters) higher by the end of the century compared to today, according to researchers who published in Monday’s Proceedings of the National Academies of Sciences.

Sea level rise is caused by warming of the ocean and melting from glaciers and ice sheets. The research, based on 25 years of satellite data, shows that pace has quickened, mainly from the melting of massive ice sheets. It confirms scientists’ computer simulations and is in line with predictions from the United Nations, which releases regular climate change reports.

coastalfloodtweet

“It’s a big deal” because the projected sea level rise is a conservative estimate and it is likely to be higher, said lead author Steve Nerem of the University of Colorado.

Outside scientists said even small changes in sea levels can lead to flooding and erosion.

“Any flooding concerns that coastal communities have for 2100 may occur over the next few decades,” Oregon State University coastal flooding expert Katy Serafin said in an email.

Of the 3 inches (7.5 centimeters) of sea level rise in the past quarter century, about 55 percent is from warmer water expanding, and the rest is from melting ice.

But the process is accelerating, and more than three-quarters of that acceleration since 1993 is due to melting ice sheets in Greenland and Antarctica, the study shows.

Like weather and climate, there are two factors in sea level rise: year-to-year small rises and falls that are caused by natural events and larger long-term rising trends that are linked to man-made climate change. Nerem’s team removed the natural effects of the 1991 Mt. Pinatubo eruption that temporarily chilled Earth and the climate phenomena El Nino and La Nina, and found the accelerating trend.

Sea level rise, more than temperature, is a better gauge of climate change in action, said Anny Cazenave, director of Earth science at the International Space Science Institute in France, who edited the study. Cazenave is one of the pioneers of space-based sea level research.

floodingsandy

Global sea levels were stable for about 3,000 years until the 20th century when they rose and then accelerated due to global warming caused by the burning of coal, oil and natural gas, said climate scientist Stefan Rahmstorf of the Potsdam Institute in Germany, who wasn’t part of the study.

Two feet of sea level rise by the end of the century “would have big effects on places like Miami and New Orleans, but I don’t still view that as catastrophic” because those cities can survive — at great expense — that amount of rising seas under normal situations, Nerem said.

But when a storm hits like 2012’s Superstorm Sandy, sea level rise on top of storm surge can lead to record-setting damages, researchers said.

Some scientists at the American Geophysical Union meeting last year said Antarctica may be melting faster than predicted by Monday’s study.

Greenland has caused three times more sea level rise than Antarctica so far, but ice melt on the southern continent is responsible for more of the acceleration.

“Antarctica seems less stable than we thought a few years ago,” Rutgers climate scientist Robert Kopp said.

Inside Climate News:

The rate of sea level rise is accelerating so fast that some coastal communities could confront an additional 4 inches per decade by the end of the century—a growing concern now confirmed by thorough measurements from space.

At that rapid pace of change, vulnerable communities might not be able to keep up. Storm surges will increase erosion and damage homes, businesses and transportation infrastructure in some areas. In other places, seawater will intrude on freshwater aquifers. In South Asia and the islands, people will lose the land where they live and farm. And the changes will arrive much faster than they do today.

Study author – “..conservative estimate.”

NASA: 

This acceleration, driven mainly by increased melting in Greenland and Antarctica, has the potential to double the total sea level rise projected by 2100 when compared to projections that assume a constant rate of sea level rise, according to lead author Steve Nerem. Nerem is a professor of Aerospace Engineering Sciences at the University of Colorado Boulder, a fellow at Colorado’s Cooperative Institute for Research in Environmental Sciences (CIRES), and a member of NASA’s Sea Level Change team.

If the rate of ocean rise continues to change at this pace, sea level will rise 26 inches (65 centimeters) by 2100 — enough to cause significant problems for coastal cities, according to the new assessment by Nerem and colleagues from NASA’s Goddard Space Flight Center in Greenbelt, Maryland; CU Boulder; the University of South Florida in Tampa; and Old Dominion University in Norfolk, Virginia. The team, driven to understand and better predict Earth’s response to a warming world, published their work Feb. 12 in the journal Proceedings of the National Academy of Sciences.

“This is almost certainly a conservative estimate,” Nerem said. “Our extrapolation assumes that sea level continues to change in the future as it has over the last 25 years. Given the large changes we are seeing in the ice sheets today, that’s not likely.”

Rising concentrations of greenhouse gases in Earth’s atmosphere increase the temperature of air and water, which causes sea level to rise in two ways. First, warmer water expands, and this “thermal expansion” of the ocean has contributed about half of the 2.8 inches (7 centimeters) of global mean sea level rise we’ve seen over the last 25 years, Nerem said. Second, melting land ice flows into the ocean, also increasing sea level across the globe.

These increases were measured using satellite altimeter measurements since 1992, including the Topex/Poseidon, Jason-1, Jason-2 and Jason-3 satellite missions, which have been jointly managed by multiple agencies, including NASA, Centre national d’etudes spatiales (CNES), European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), and the National Oceanic and Atmospheric Administration (NOAA). NASA’s Jet Propulsion Laboratory in Pasadena, California, manages the U.S. portion of these missions for NASA’s Science Mission Directorate. The rate of sea level rise in the satellite era has risen from about 0.1 inch (2.5 millimeters) per year in the 1990s to about 0.13 inches (3.4 millimeters) per year today.

“The Topex/Poseidon/Jason altimetry missions have been essentially providing the equivalent of a global network of nearly half a million accurate tide gauges, providing sea surface height information every 10 days for over 25 years,” said Brian Beckley, of NASA Goddard, second author on the new paper and lead of a team that processes altimetry observations into a global sea level data record. “As this climate data record approaches three decades, the fingerprints of Greenland and Antarctic land-based ice loss are now being revealed in the global and regional mean sea level estimates.”

UPDATE:

Oceanographer Stefan Rahmstorf tweets me:

Advertisements

6 Responses to “Satellites: Sea Level Rise Accelerating”

  1. Sir Charles Says:

    Well. The study concludes a ‘conservative estimate’…

  2. neilrieck Says:

    Science tells us that the ocean levels rose 20 cm (8 inches) from 1900 to 2000 which translates into a rate of 2 mm/year. But things got worse when satellites launched in the early 1990s noticed a measured rate of 2.9 (to 3.4) mm/year. Even if you use the lower number (2.9), the current measured rate of rise is 50% higher than the past 100 year average. This is the main reason why 97% of all peer-reviewed climate scientists trust the claim that the world is continuing to warm.

    https://en.wikipedia.org/wiki/Sea_level_rise

  3. grindupbaker Says:

    Somebody made an interesting comment against a talk on video by Eric Rignot. Where Eric showed a cartoon of Antarctic ice shelf being undercut at the face at the grounding line by warm, deep water after mentioning earlier that Westerly winds push surface water north (Ekman) so deep water goes south (stronger Westerly winds now due to tropics warming faster than Antarctica), this commenter person pointed out that ice melting at the face freshens the water there so the pressure is less than further north causing deep water to force south (under an ice shelf where there’s no wind). If that’s a significant factor, which seems reasonable, then that’s interesting because it’s a classic positive feedback if the water warms. Warmer melts ice faster –> more fresh water near the face –> more pressure difference –> faster current in and out –> melts ice even faster –> even more fresh water near the face –> even more pressure difference –> even faster current in and out, and so on. If that’s correct then a faster current should be noted with warmer deep water.

  4. dumboldguy Says:

    More info about accelerating sea level rise is not really news—-it’s just part of the constant avalanche of information that confirms the reality of AGW and points to ever-worsening future studies/discoveries/surprises. The REAL news is that Fox and Breitbart seem to be noticing and mentioning it. Is there hope?


Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: