"West Coast Sea Level Dropping" - oceanographer tells it like it is

Spartan Daily, the college newspaper of San Jose State University (California), has a report on a talk given by Larry Breaker, adjunct professor of physical oceanography at Moss Landing Marine Laboratories to students there,

New studies show regional sea levels are dropping on the West Coast even though global sea level rise is accelerating.

“Regional sea level rise is not uniform around the world,” said Larry Breaker, adjunct professor of physical oceanography at a talk at Moss Landing Marine Laboratories last week. “Although sea level is rising in some areas, in other areas it’s falling.”

Other studies (including mine, of course) have shown the same about US west coast sea-levels, though you'd not think so given the almost total silence on the issue in the media. Several of the students showed an alarming ignorance on the subject, given that they're studying at a marine laboratory.

“I was surprised to hear that,” said Moss Landing Marine Labs graduate student Christian Denney. “The concept that the local sea level was different from the global mean is new to me.” 

“(The sea level) has been steadily rising since the 1930s,” said Moss Landing Marine Labs graduate student Dorota Szuta. “But I didn’t realize that the sea level had actually been falling on the west coast of North America.”

And so it has, but the concept that the world climate and other metrics are anything but uniform shouldn't be news to anyone, especially students in a scientific discipline such as these two. I was going to say full marks to the prof. for telling it like it is, and so I do, but I shouldn't need to - isn't truth the universal standard in science?

More from the prof. -

“With GPS data we can now estimate local subsidence and uplift in the vicinity of many tide gauges,” he said. "Recently acquired GPS data near the San Francisco tide gauge suggests that it could be subsiding at rates approaching one millimeter per year."

Now that's interesting (at least to me) as I haven't been able to acquire any up-to-date GPS info for the US west coast. If you're interested, read the article for a few more interesting observations by the prof., and read his profile for even more interesting stuff - his experience in things oceanic is extensive. How refreshing to report on something in a positive light for a change, and not have to take a poke at anyone about what they've said or written (a few students excepted, of course).

The South-west "Cold Spot" - the other side of the coin

There was a lot in the press and on blogs back in June about the so-called "North-east Hot Spot" or NEH, an invention of the US Geological Survey. The authors of the USGS paper know what the weaknesses of their argument are, I'm sure - if they don't know, then they should have left their paper languishing in the "pending" tray. I'm planning another post on that subject soon, but there are two sides to every story, and there are two sides to every continent. If there's a "North-east hot spot", is there perhaps a "South-west cold spot"? There is indeed - and along a coast which is also subsiding slowly (which tends to raise sea level relative to the land), from San Diego in the south to just north of San Francisco, sea level hasn't risen in the last three decades. There are reasons for this of course, just as there are reasons behind the claimed "acceleration" in the north-east, but unlike the USGS authors, I'll not skate over or omit them. In my post on the continuing moderate sea-level rise around the Hawaiian Islands, I included this satellite graphic.

Map 1 - Linear trend (1993-2010) of satellite altimeter sea surface height showing he region of high rates in the western Tropical Pacific (Source)

I accept the data summarised therein, but it's a bad graphic - there's hardly any difference in the colours used for small negative, and small positive trends. Whether that's deliberate of not, I can't say, but the same criticism can't be levelled at this graphic representing a  slightly shorter period (to 2008). Its authors chose a switch from bright green to bright yellow either site of the scale zero, and I applaud them for it.

Map 2   Source: Why sea level rise isn’t level at all (NASA blog)

What stands out is the swathe of green (negative change) from Alaska down along the US west coast to Mexico and beyond. Incidentally, some sceptics (who should know better) have scoffed at graphics such as these, claiming that the very high rates of increase shown in the western Pacific are "fiction", and therefore the entire maps aren't to be trusted. I tended to agree (mea culpa) , until I began actually checking the depicted rates against tide gauge data over the time period(s) of the map(s). To date I've not found any but minor discrepancies, and where it's possible to take account of changes in land (and therefore gauge) height any such differences are mostly of the order of a few tenths of a mm/year at the very most.

However, looking at some of the actual plots will illustrate the situation and confirm the veracity of the satellite data. I initially planned to start in the south and work northwards, but decided to show what I think is the most interesting plot, for Port San Luis, N of Santa Barbara.

Note that while there is, overall, a small rate of rise (0.65 mm/year), the level since 1996 is lower than the 5-year-average peak in 1959. The level since 1980 is falling:

Port San Luis, CA                                                                          source: PSMSL

I'm not stating that sea level will continue to fall at Port San Luis. I'm not even suggesting it. I'm merely pointing out what is happening now (to the end of the last complete year of published data), and what has happened in recent decades.

My question at this point is whether city and state planners, local businesses and citizens actually know that sea level along the Californian coast has been stable for decades, and has been falling at almost all gauge sites for the last decade or two? If not, why not? Authorities around San Francisco Bay are wetting themselves about possible huge future sea level rise "predictions", and many appear to have convinced themselves that effects such as beach erosion are due to recent sea level rise, when the records show nothing of the sort. For example, there's been a gauge at Alameda Naval Air Station (East across the Bay from San Francisco) since 1939.

Alameda (Naval Air Station), CA                                                 source: PSMSL

... where the current 5-year average is lower than it was in the late 1960s, and the current rate is clearly negative. Most assessment reports I've seen brush the inconvenient facts "under the carpet" and only mention global data and the scary predictions. Some (see Missing the Point in California) are so mesmerised by this misinformation they can't see what's under their noses. There's no doubt that sea levels are rising globally. There's no doubt that effects such as ENSO raise and lower sea levels across the Pacific. The peaks from the strong 1982-3 and 1997-8 El Niños stand out for the two previous examples, and for all west-coast sites from southern California to Alaska. The Pacific Decadal Oscillation has an impact - it was strongly positive from the late 1970s to around 2008, and in that phase tends to raise sea levels in the west, and lower them in the east, our area of study.

Is the story the same at all stations in California? Not quite - Humboldt Bay (about 120 km S of the Oregon state line) is an outlier, and shows up on map 2 above (click to get the original) as a pale orange blob at the apex of the "bulge" of the Californian coast.

Source: PSMSL

Note however, that while the calculated trend is 4.7 mm/year overall, the rolling profile of the 3-year moving average is similar to the previous examples, and this indicates that North Spit must be sinking at a greater rate than other sites to the south, and a greater rate than the sea level is falling, resulting in a small positive rate since the early 1990s.

Plots for San Francisco and Point Reyes can be seen here, and data for all the west coast stations are linked on the Permanent Service for Mean Sea Level (PSMSL) page here - scroll down three-quarters of the page on the scroll bar.

Things will change, there's no doubt, but precisely which way, and to what extent, no one knows. Now that's a fact. Don't believe what you read, not even what you read here. I do my best to be truthful and unbiased, but I still have an overall point of view, and it may colour my presentation of what I see as facts. Check my references, check other blogger and web author's references, and remember - the truth may only be a click away (or two clicks if you have Windows Vista).

Missing the Point in California

We read a sad tale on the Climate Watch blog - Rising Seas Threaten California’s Coastal Past, "Higher tides and increased erosion will wipe out archaeological sites"

This site and these cultural resources — some of them a thousand years old or more — might not be around for much longer. These pieces of California’s history are in danger of disappearing as the Pacific Ocean claws at the base of this cliff. Sea level rise is accelerating the problem.

It’s not just that the tides will be higher. The cliffs are so soft, they could recede hundreds of feet back, with just a few feet of sea level rise.

So "sea level rise is accelerating the problem", and the evidence for that is...?

A tide gauge in the nearby Golden Gate has recorded eight inches of sea level rise in the past century. Scientists project it could rise three feet in the next.

That "whole eight inches" (20cm) is indisputable, the record shows it, and it's equal to the average global rise during the 20th century, but "accelerating the problem"? Mr. Newland, an archaeologist at Sonoma State University and the president of the Society for California Archaeology, seems to think so, but why, if he's so concerned about Point Reyes, is he quoting a statistic for San Francisco, when there's a gauge right on his doorstep at Point Reyes lighthouse? Perhaps this is the reason:

Source: PSMSL

... just about zero rise since 1980, clearly shown by the 5-year (61 month) moving average. This is in common with most stations from Point Reyes southward, including his quoted San Francisco. Sea level rise along this coast is a documented non-problem at the moment, and has been so for 30 years.

Source: PSMSL

I sympathise with him, but before blaming some "climate change" induced effect for what's happening, make sure you're in possession of the facts. Soft rock erodes quickly with wave action, rising sea level or not - it's part of a natural cycle, returning sediment to the sea floor to form new rock in time.

Local and city authorities are scurrying about, wringing their hands in despair, worrying about inundation of wetlands, coastal highways and houses, when sea levels along the Californian coast aren't rising, and haven't risen for around 30 years. In North Carolina, state legislators have taken a pragmatic "wait and see" approach to sea level rise and have been castigated for their common sense, The cries of "we have to act now" are nonsensical. They have to act on what's happening now, and make plans for the foreseeable future If an acceleration establishes itself, there'll be plenty of time to bring forward future plans, and formulate new ones.

In the case of Point Reyes, Mr. Newland should cite facts, not "climate-change" sound-bites to bolster his case for action. Unfortunately, this tactic is rapidly becoming the norm.

Global Warming through the eyes of a True Believer

I was looking for something totally unrelated to global warming, climate change, blind meteorologists etc., when I stumbled upon "Golden State Heating Up, Study Finds" from 2007 on PhysOrg - not a site I've ever spent any time on in the past. I have seen a few links on Google News, but the brief summaries usually put me off - the site seems to be the haunt of dyed-in-the-wool believers in "settled science".

Average temperatures in California rose almost one degree Celsius (nearly two degrees Fahrenheit) during the second half of the 20th century, with urban areas blazing the way to warmer conditions, according to a new study by scientists at NASA and California State University, Los Angeles.

Of course, those who don't acknowledge the significance of the Urban Heat Island (UHI) effect wouldn't see the irony in that "urban areas blazing the way to warmer conditions".

The scientists found great variations in temperature patterns throughout the state. Average temperatures increased significantly in nearly 54 percent of the stations studied, with human-produced changes in land use seen as the most likely cause. The largest temperature increases were seen in the state's urban areas, led by Southern California and the San Francisco Bay area, particularly for minimum temperatures. Minimum temperatures at some agricultural sites showed increases comparable to some urban areas. Rural, non-agricultural regions warmed the least. The Central Valley warmed slowest, while coastal areas warmed faster, and the southeast desert warmed fastest.

Note "particularly for minimum temperatures" and "Rural, non-agricultural regions warmed the least" - the signature of UHI. No mention of that here, of course.

The paper (no title nor date mentioned - very useful) would seem to be LaDochy, S., R. Medina, W. Patzert (2007): Recent climate variability in California: Spatial and temporal variations in temperature trends, Climate Research CR 33:159–169. The trio seem to be unaware of UHI - in fact in their paper they say (thanks, CO2 Science)

"the small increases seen in rural stations can be an estimate of this general warming pattern over land," which implies that "larger increases," such as those found in areas of intensive urbanization, "must then be due to local or regional surface changes."

However, the thrust of this post is not directed at Medina et.al., but at the original NASA/JPL author of the article, for below my last quote from that is this graphic:

In Los Angeles, average annual temperatures have increased steadily over the past 130 years. Image credit: NASA/JPL/Cal State L.A.

Notice "increased steadily over the past 130 years". The author clearly is looking at the chart with the eyes of a "True Believer". He appears to be looking at the red trend line, not the (unsteady) blue running average, not the fact that temperatures after the 1997 peak dropped to lower than the late 1960s/early 1970s. The blue running average shows that clearly. The nearest I can get to that chart is this one from GISS, but it's very similar, except for the missing early 80s peaks.

Los Angeles annual temperatures 1881-2011 GHCN via GISS

The red running mean has dropped to the 1955/6 level, similar to that for 1976. Of course, if I were a "True Believer" I'd just not see that. Perhaps "True Believers" look at temperature graphs with a right tilt to the head, which always produces a "steady increase", and snowfall graphs with a tilt to the left, which produces a vague childhood memory of what snow looked like.