Curry’s sea-level rise study disputes climate-disaster predictions – In many cases, ‘half of the sea-level rise is really from land sinking’

By Valerie Richardson – The Washington Times

For years, climate prognosticators have warned that human-caused global warming is fueling catastrophic sea-level rise, but now climatologist Judith Curry is rocking their boat.

In her latest paper, Ms. Curry found that the current rising sea levels are not abnormal, nor can they be pinned on human-caused climate change, arguing that the oceans have been on a “slow creep” for the last 150 years — before the post-1950 climb in carbon-dioxide emissions.

“There are numerous reasons to think that projections of 21st-century sea level rise from human-caused global warming are too high, and some of the worst-case scenarios strain credulity,” the 80-page report found.

Her Nov. 25 report, “Sea Level and Climate Change,” which has been submitted for publication, also found that sea levels were actually higher in some regions during the Holocene Climate Optimum — about 5,000 to 7,000 years ago.

“After several centuries of sea level decline following the Medieval Warm Period, sea levels began to rise in the mid-19th century,” the report concluded. “Rates of global mean sea level rise between 1920 and 1950 were comparable to recent rates. It is concluded that recent change is within the range of natural sea-level variability over the past several thousand years.”

Then again, Ms. Curry is accustomed to making waves. The former chair of the Georgia Tech School of Earth and Atmospheric Sciences, she represents one of the biggest names on the so-called “skeptic” side of the climate debate, the counterweight to Penn State climatologist Michael Mann, who leads the “warmist” camp.

She said the problem is that the disaster scenarios are driven by the most extreme forecasts of carbon-dioxide emissions, known as RCP8.5, which she and other critics have described as so extreme as to be implausible.

“[President] Trump, he said something about people talking about the extreme scenarios — well, they are,” Ms. Curry told The Washington Times. “Consideration of extreme scenarios has some value, but they’re portrayed as the expected outcome, and that’s really not useful.”

She argued that a more appropriate estimate would be about 0.2 to 1.5 meters, or six inches to five feet, and that anything over two feet is “increasingly weakly justified.” Mean sea level has risen by about seven to eight inches since 1900.

By lending her prestige to the sea-level debate, she could chill the rash of lawsuits filed by cities and counties in California, Colorado and New York—as well as the state of Rhode Island — calling for oil-and-gas companies to pay billions in damages associated with future coastal flooding.

Ms. Curry agreed that there is a human-caused component to the problem, but said it has more to do with the earth sinking than the oceans swelling.

“In most of those cases where they’re suing, half of the sea-level rise is really from the land sinking, rather than anything that the ocean is doing,” she said. “If you look at Galveston and New Orleans, much more than half is caused by sinking. And this comes from geologic processes, it comes from landfills on wetlands.”

She cited groundwater withdrawal in the Chesapeake Bay area, which has also caused sinking.

“That’s really underappreciated, this whole issue of problems with coastal engineering that we’ve caused that have made things worse,” Ms. Curry said.

Challenging her sea-level conclusions are scientists like Mr. Mann. In a June debate with Ms. Curry at the University of Charleston in West Virginia, he argued that the latest models show that “ice sheets can collapse more quickly than we thought.”

“If you had asked us five years ago what the best estimate was of the sea level rise we could see by the end of the century, we would have told you three feet,” he said, adding, “Well, now if you ask us, we have to say, it may be closer to six to eight feet.”

She and Mr. Mann have sparred before. At a March 2017 congressional committee hearing, he denied calling her a “climate science denier, to which she retorted, “It’s in your written testimony. Go read it again.”

“I think he’s learned that there’s a lot of backlash when he calls me a denier, so he calls me a contrarian,” said Ms. Curry with a laugh. “And I don’t think he’s really mentioned me much lately. I think he’s been burned.”

She said she doesn’t believe her findings on sea-level rise are particularly controversial, saying that they jibe with those of the U.N.’s Intergovernmental Panel on Climate Change.

“It’s pretty well-documented in the literature,” said Ms. Curry. “I frame the problem a little different, and my conclusions are a little different than some people, but this has been pretty well-documented and supported.”

Ms. Curry left academia in January 2017 for a host of reasons, one of which was the “craziness” associated with the politics of the climate-change debate. She moved to Reno and has since devoted her energies to her company, Climate Forecast Applications Network.

Her clients include the federal agencies and companies in the energy and insurance business seeking answers on the risks associated with climate change. After a lifetime spent in the ivory tower, she said she finds the real-world work rewarding.

“When there’s something that really depends on the outcome and the understanding of this information, rather than just using it as a political tool to drive policy, it’s really a different ballgame,” she said. “People making real decisions, people spending real money — their companies could be hurt by getting things really wrong in either direction. So that’s what I’m trying to help with.”

Given that nobody wants to be labeled a “denier,” what does she prefer to be called? That’s an easy one.

“I’m a scientist. And I regard it as my job to continually reevaluate the evidence and reconsider my conclusions. That’s my job,” Ms. Curry said. “And some people don’t really want scientists. They want political activists. But if you want a scientist, give me a call.”

Full story here

The complete report can be downloaded here [Special Report- Sea Level Rise].

Figure 2.2: Regional mean sea level trends over the 1993-2014 period (Ablain et al. 2016)

Executive Summary
This Report assesses the scientific basis for projections of future sea level rise. The Report evaluates the projections from the Intergovernmental Panel on Climate Change (IPCC) and recent national assessments regarding sea level rise. The uncertainties and challenges at the knowledge frontier are assessed in the context of recent research, particularly with
regards to natural variability.

The following four issues frame this Report:

1. Whether recent global sea level rise is unusual.
At least in some regions, sea level was higher than present around 5000 to 7000 years ago.
After several centuries of sea level decline following the Medieval Warm Period, sea
levels began to rise in the mid 19th century. Rates of global mean sea level rise between
1920 and 1950 were comparable to recent rates. It is concluded that recent change is
within the range of natural sea level variability over the past several thousand years.

2. The extent to which recent global sea level rise is caused by human-caused global
warming, relative to natural causes of global sea level rise.

The slow emergence of fossil fuel emissions prior to 1950 did not contribute significantly
to 19th and early 20th century sea level rise. Identifying a potential human fingerprint on
recent sea level rise is confounded by the large magnitude of natural internal variability
associated with ocean circulation patterns. There is not yet any convincing evidence of
such a fingerprint on sea level rise associated with human-caused global warming.

3. The extent to which local sea level rise is influenced by the global sea level rise,
relative to local vertical land motion and local land use practices.
In many of the most vulnerable coastal locations, the dominant causes of local sea level
rise problems are natural oceanic and geologic processes and land use practices. Land use
and coastal engineering in the major coastal cities have brought on many of the worst local
problems, notably landfilling in coastal wetland areas and groundwater extraction.

4. The amount of sea level rise (global and local) projected for the 21st century.
Local sea level in many regions will continue to rise in the 21st century – independent of
global climate change. There are numerous reasons to think that projections of 21st century
sea level rise from human-caused global warming are too high, and some of the worst-case
scenarios strain credulity.

Understanding climate change and sea level rise involves incomplete information from a
fast-moving and irreducibly uncertain science. The challenges of understanding the causes
of sea level rise and projecting future climate change and sea level rise are well recognized by the international community of climate and sea level researchers, as summarized in the World Climate Research Programme (WCRP) Grand Challenges.

via Watts Up With That?

December 28, 2018 at 08:06PM

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