Reuters Misleading Report On Rising Sea Levels

By Paul Homewood

 

 

http://www.reuters.com/investigates/special-report/waters-edge-the-crisis-of-rising-sea-levels/

 

Reuters have produced a woefully misleading piece about rising sea levels off the US coast. The first two paragraphs set the tone and includes the first factual error, with talk of melting of polar ice, a force contributing to a global rise in ocean levels. As they should know, melting of sea ice has no effect on sea level.

The very first sentence stating that flooding is getting worse, together with the “warming planet over the past 20 years”, is clearly designed to convey the message that sea levels must be rising faster then ever.

This is reinforced by showing the number of days of flooding, for instance:

The analysis was then narrowed to include only the 25 gauges with data spanning at least five decades. It showed that during that period, the average number of days a year that tidal waters reached or exceeded flood thresholds increased at all but two sites and tripled at more than half of the locations.

Of course, all this means is that sea levels are a bit higher than before, not that they are rising faster.

Their emphasis on climate change as the problem can also be seen in this paragraph:

These findings, first reported July 10, aren’t derived from computer simulations like those used to model future climate patterns, which have been attacked as unreliable by skeptics of climate change research. The analysis is built on a time-tested measuring technology – tide gauges – that has been used for more than a century to help guide seafarers into port.

 

 

The article concentrates heavily on Chesapeake Bay, where sea level is rising at the fastest rate, as shown for instance on their graph for Baltimore.

 

 

What they fail to point out is the fact that Chesapeake Bay sits on an impact crater, believed to have been formed when a large comet or meteor struck the earth approximately 35 million years ago. As a result, the land is sinking in the region.

This effect is added to the more general sinking of the land down the whole of the whole of the US eastern seaboard, following the end of the ice age, as this paper by Boon et al,  Chesapeake Bay Land Subsidence and Sea Level Change makes clear.

Subsidence, or the downward movement of the earth’s crust relative to the earth’s center, is particularly evident in the mid-Atlantic section of the U.S. east coast. Engelhart et al. (2009)

used a geological database of late Holocene sea level indices to estimate subsidence rates of <0.8 mm/yr in Maine increasing to 1.7 mm/yr in Delaware before returning to rates <0.9 mm/yr in the Carolinas.

 

The authors include this table.

 

 

RSL reflects the actual sea levels, as measured by tide gauges, while the ASL takes out the effect of sinking land. As can be seen, apart from the anomaly at Cambridge, the other stations show ASL of 1.41mm/yr or less, about 5 inches/century. This is a far cry from the headline figures shown for Baltimore of 12 inches/century.

 

Boon et al show the subsidence rates at the ten stations they have based their analysis on.

 

 

In other words, subsidence is at least as big a problem as global sea level rise, and in some places much more so. I find remarkable that Reuters have not highlighted this issue.

 

To be fair, they do include this small paragraph, way down their article:

In many places, including much of the U.S. Eastern Seaboard, an additional factor makes the problem worse: The land is sinking. This process, known as subsidence, is due in part to inexorable geological shifts. But another major cause is the extraction of water from underground reservoirs for industrial and public water supplies. As aquifers are drained, the land above them drops, a process that can be slowed by reducing withdrawals.

But as we know, readers impressions are formed by the headlines and the first few paragraphs, and many won’t even make it to the end of the report to read a paragraph that does little to convey the scale of the subsidence problem.

Any doubts readers may have are soon put aside by this statement a few paragraphs later:

The Reuters analysis shows that the “impacts of climate change-related sea level rise are increasing frequencies of minor coastal flooding,” said William Sweet, an oceanographer for NOAA who led a team of scientists that released similar findings in late July. The NOAA study examined 45 gauges and found that flooding is increasing in frequency along much of the U.S. coastline and that the rate of increase is accelerating at sites along the Gulf and Atlantic coasts.

 

 The Facts

So what are the facts? Boon et al include this useful table, which compares sea level rise from 1944-75 with 1976-2007.

 

To all intents and purposes, the rate of sea level rise is unchanged, rather scotching the argument that climate change is making things worse.

Note also that the figures at Baltimore, a long running station also show no acceleration since the 1912-43 period. This is confirmed by NOAA’s analysis of 50-Year mean trends, which show that the fastest rate of rise was 1925-75.

 

http://tidesandcurrents.noaa.gov/sltrends/50yr.shtml?stnid=8574680

 

 

Global sea level has been rising steadily since the 19thC at a rate of about 7 inches/century, as global temperatures recovered from the LIA, a period of falling sea levels. HH Lamb has written that sea levels during the Middle Ages, and also around 400 AD, were comparable with, or slightly above, present. There should really be little surprise that they have slightly recovered since.

There is no evidence that most of the recent rise is not due to natural factors.

Sea level rise certainly poses problems for the US east coast, but to a large extent this is due to subsidence. The naive belief that we can somehow halt the rise of the oceans carries the very real danger that we ignore the geological side of the problem. 

 

Meanwhile, Reuters quote:

Sea level rise has become mired in the debate over climate change. And on climate change, the politically polarized U.S. Congress can’t even agree whether it’s happening.

The stalemate was on display in May, when the administration of President Barack Obama released its updated National Climate Assessment. The 841-page report was five years in the making, with input from more than 300 scientists, engineers, government and industry officials and other experts, a 60-member advisory committee and more than a dozen federal departments and agencies. It was among the first major assessments of climate change to move from predictions of disaster to point out the effects that can already be seen: record-setting heat waves, droughts and torrential rains.

At or near the top of the list of the most pressing concerns is “the issue of sea level rise along the vast coastlines of the United States,” Jerry Melillo, a scientist at the Marine Biological Laboratory in Woods Hole, Massachusetts, and chairman of the advisory committee, said at a briefing on the report.

 

 And what does the National Climate Assessment have to say about sea level rise?

 

http://nca2014.globalchange.gov/report/our-changing-climate/sea-level-rise

 

Sea levels have not been rising at 1 to 4 feet per century, and show no sign of doing so. It is a pity Reuters did not bother to acquaint its readers with the real facts.