Tag Archives: Effects of global warming

Ocean acidification gets attention in four bills passed by the U.S. House

The issue of ocean acidification gained some traction this week in the U.S. House of Representatives, where bipartisan support led to the approval of four bills designed to bring new ideas into the battle to save sea life from corrosive waters.

If passed by the Senate, the legislation would allow federal agencies to set up competitions and offer prize money for the best ideas for reducing ocean acidification, adapting to ongoing changes or solving difficult research problems. The bills also foster discussions about climate change by bringing more people to the table while providing increased attention to the deadly conditions that are developing along the coasts and in estuaries, such as Puget Sound.

U.S. Rep. Derek Kilmer

“We know that changing ocean chemistry threatens entire livelihoods and industries in our state, said U.S. Rep. Derek Kilmer, D-Gig Harbor, in a press release. “There are generations of folks in our coastal communities who have worked in fishing and shellfish growing — but that’s endangered if we don’t maintain a healthy Pacific Ocean.”

Later in this blog post, I will reflect on other Kilmer-related issues, including the so-called Puget Sound Day on the Hill.

In a phone conversation, Rep. Kilmer told me that he was encouraged with the widespread support for a bill that he sponsored called the Ocean Acidification Innovation Act of 2019 (HR 1921), which passed the House on a 395-22 vote. The bill would allow federal agencies to sponsor competitions and offer prize money for the best ideas. Money would come out of existing funds that agencies use for related purposes. The bill was co-sponsored by Northwest Reps. Jaime Herrera Beutler, R-Battle Ground, along with Rep. Suzanne Bonamici, an Oregon Democrat, and Rep. Don Young, an Alaskan Republican. Five representatives from coastal areas in other parts of the country added their names to the bill.

“There is a legitimate problem, and people are beginning to see the impacts of the changing ocean chemistry,” Derek said. “This should a bipartisan issue.”

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NASA researchers measure sea levels, predict faster rise

A new worldwide map of sea level rise, plotted with precision satellite instruments, shows that the Earth’s oceans are rising faster with no end in sight.

Sea levels have gone up an average of 3 inches since 1992, with some locations rising as much as 9 inches. Meanwhile, some limited areas — including the West Coast — have experienced declining sea levels for various reasons.

Sea level change over 22 years. Map: NASA
Sea level change over 22 years. (Click to enlarge) // Map: NASA

Two years ago, climatologists released an international consensus, which predicted a sea-level rise of between 1 and 3 feet by the end of this century. It was a conservative estimate, and new evidence suggests that ocean waters are likely to meet or exceed the top of that range, possibly going much higher, according to four leading researchers speaking at a news conference yesterday.

The implications are huge and growing more important all the time. At a minimum, waterfront property owners and shoreline planners need to begin taking this into consideration. It doesn’t make sense to build close to the shoreline if extreme high tides will bring seawater to one’s doorstep.

If we hope to avoid local extinctions of key intertidal species, we must start thinking about how high the waters will be in 50 to 100 years.

For clues to the future, we can watch Florida, where vast areas stand at low elevations. Even now, during high tides, Miami is beginning to see regular flooding in areas that never got wet before. This is the future of low-lying areas in Puget Sound, such as estuaries. In the Pacific ocean, the threat of inundating complete islands is becoming very real.

Along the West Coast, sea levels have actually declined over the past 20 years, largely because of the cooling effect of the Pacific Decadal Oscillation, a warming/cooling cycle that can remain in one phase for decades. The cycle appears to be shifting, with the likely effect that sea levels on the West Coast will soon rise as fast or faster than the worldwide average, according to Josh Willis, an oceanographer at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

Global sea level has been measured accurately and continuously by satellites since 1993. Graphic: Steve Nerem, University of Colorado
Global sea level has been measured accurately and continuously by satellites since 1993.
Graphic: Steve Nerem, University of Colorado

The cause of sea level rise is attributed to three factors. Scientists estimate that roughly one-third of the rise is caused by thermal expansion of ocean waters, which absorb much of the energy from global warming. Another third comes from the melting of the massive Greenland and Antarctic ice sheets. The remaining third comes from the melting of mountain glaciers throughout the world. Researchers at yesterday’s news conference said they expect the melting to accelerate.

Measuring the change in sea-level rise has become possible thanks to advanced technology built into altimeters carried aboard satellites. The instruments can distinguish changes in elevation as small as one part in 100 million.

“The instruments are so sensitive that if they were mounted on a commercial jetliner flying at 40,000 feet, they could detect the bump caused by a dime lying flat on the ground,” said Michael Freilich, director of NASA’s Earth Science Division.

While sea level rise can now be measured, predicting the rate of future rise is difficult, because much of the melting by ice sheets occurs out of sight under the water.

The Greenland ice sheet covers 660,000 miles — nearly the size of Alaska. Satellite measurements have shown that an average of 303 gigatons of ice have melted each year over the past decade. The Antarctic ice sheet has lost an average of 118 gigatons per year, but some new studies suggest it could begin to melt much faster.

In Greenland, researchers are reporting that one of the largest chunks of ice ever to break away from land cleaved from the Jakobshavn glacier in a “calving” event that left researchers awestruck. More than 4 cubic miles of ice was loosed quickly into the sea. Check out the news release by the European Space Agency.

“This is a continuing and evolving story,” glaciologist Eric Rignot said during yesterday’s news conference. “We are moving into a set of processes where we have very tall calving cliffs that are unstable and start fracturing and break up into icebergs …

“We have never seen something like this on that scale before,” said Rignot, associated with JPL and the University of California at Irvine. “Personally, I am in awe at seeing how fast the icefall, the calving part of the glacier, is retreating inland year by year.”

Other new information from NASA, including lots of graphics:

The following video tells the basic story about sea level rise.

A few answers regarding sea level rise

Because of the holidays, I did not get an immediate response from several climate experts I contacted following Nels Sultan’s comments about sea level rise in a blog post regarding “king tides.”

Earth at the winter solstice, Dec. 22, 2011 / NOAA photo

If you recall, Nels was making the point that the sea level in Seattle has been rising at a steady rate of .68 feet, or about 8 inches, per century since 1898, as reported by the National Oceanic and Atmospheric Administration.

His post included this statement:

“There is no real basis for the claims that sea levels will rise by 2.6 feet or 7 feet, or more. Globally, sea level rise has NOT accelerated. As found and reported by many researchers who specialize in this, including the eminent professor Bob Dean and other coastal experts.”

As a reporter, I’m not inclined to shoot back a response. I’d rather discuss the issue with experts in the field. That is what I did, and I think I have a better handle on the issue.

What I’m hearing is that the original estimates by the Intergovernmental Panel on Climate Change — a rise of between 7 inches and 2 feet by the end of the century — remain reasonable, but conservative given that they did not account for increased melting of the Greenland ice sheet. See this explanation by Stefan Rahmstorf soon after the release of the 2007 IPCC report. By the way, the range above accounts for the minimum and maximum across six climate-change scenarios.

Ever since, researchers have been trying to find ways to account for the melting of the Greenland ice sheet, but the uncertainties remain high. A widely cited paper by W.T. Pfeffer, J.T. Harper and S. O’Neel suggests that “most likely” starting point for further refinement is .8 meter, or 31 inches, of sea level rise by 2100.

In some ways, the authors of the Pfeffer paper were trying to limit some of the extremes being reported by others, so they concluded that sea level rise could not be more than 6 feet by 2100. Some folks have reported 6 feet as the top of the range, as unlikely as that extreme may be. Check out this explanation posed by Real Climate and this response by Pfeffer and his collaborators.

As for the Houston-Dean paper that Nels Sultan mentioned, those authors created “various problems” in their assumptions, according to Eric Steig, professor of Earth and Space Sciences at the University of Washington. One major problem was the starting date of 1930, as explained by Stefan Rahmstorf in Real Climate:

“Other start dates either before or after this minimum show positive acceleration. Picking 1930 for this analysis is thus a classic cherry-pick, and according to the authors that is no accident. They write in the paper: ‘Since the worldwide data of Church and White (2006)…appear to have a linear rise since around 1930, we analyzed the period 1930 to 2010.’ The interval was thus hand-picked to show a linear rise rather than acceleration.

“Houston & Dean use their result to question the future acceleration of sea level rise predicted by Vermeer & Rahmstorf (2009) for the 21st Century as a consequence of global warming. They argue that the 1930s acceleration minimum calls into question the semi-empirical link between global temperature and global sea level proposed by us in that paper. However, it is clear they never bothered to check this, because quite the opposite is the case: our semi-empirical formula predicts this acceleration minimum, as the graph above shows. As it turns out, this is an expected outcome of the mid-20th-Century plateau in global temperature.”

I also discussed this issue of sea level rise with Lara Whitely Binder, outreach specialist for the UW’s Climate Impacts Group. While sea level rise means one thing on the world scale, she told me, the local impacts can be quite different.

If you live in Neah Bay on the Olympic Peninsula, for example, you are not likely to see any sea level rise until at least 2080. That’s because the entire land mass is uplifting as a result of movement along the tectonic plates, and the uplift is predicted to be faster than sea level rise until late in the century.

On the other hand, Central and South Puget Sound may not be uplifting at all and could be sinking, which would intensify the effects of sea level rise. Areas built on fill, including portions of Olympia, also could be sinking as the fill settles, Lara said.

In addition to global rise in sea level and local tectonic shifts, factors affecting regional sea level rise include thermal expansion of ocean waters and changes in onshore and offshore wind patterns.

During El Niño events, sea level can rise as much as 12 inches for several months at a time. The Climate Impacts Group analyzed more than 30 scenarios from global climate models and concluded that the change in wind patterns as a result of climate change could decrease sea level by as much as 1 inch or possibly increase it by as much as 6 inches. Review the white paper “Sea Level Rise in the Coastal Waters of Washington State” (PDF 2.4 mb) for more details.

How much an individual property is affected by sea level rise depends on the slope of the beach. Given the same rate of rise, water will affect a house sooner when it is built on a gradually sloping beach as opposed to a steep slope. In any case, tides and weather will always play a major role in water levels.

Lara told me that a group of West Coast researchers is working on a new report about sea level for publication later this year by the National Academy of Sciences. I’ll try to review that paper when it comes out.

I wish to thank Eric Steig, Lara Whitely Binder, Cliff Mass, David Montgomery and Nate Mantua for responding to my inquiry.