Wednesday, 29 August 2012

High and Dry in San Francisco - NOAA's Ark?

Here's a beach pic at the Presidio, north of San Francisco, not that far from the Golden Gate bridge (seen on the extreme left).

Weather's a bit dull, but there's plenty of sand on the beach. Here's a sunnier view.

The small hut on the right contains the tide gauge for San Francisco. Both pics are from the NOAA station information page for that gauge. Based on the first pic, how would you rate the chances of the gauge registering low water accurately?

Sunday, 26 August 2012

Rising sea levels throughout metro Vancouver putting landmarks at risk - Vancouver Sun

"Rising sea levels throughout metro Vancouver putting landmarks at risk" says the Vancouver Sun (my bold).
VANCOUVER, B.C.: AUGUST 1, 2012 -- Andrew Yan (L) and Michael Heeney (R) at Vancouver’s Granville Island, August 1st, where they have done a study on the rising sea levels. Dikes and other infrastructures maybe needed to protect some of Vancouver’s landmarks
Vancouver is at risk of losing landmark communities like Granville Island and False Creek unless the city starts taking measures to defend its shoreline against rising sea levels, an urban planner warns.
Andrew Yan, a planner and researcher with Bing Thom Architects, estimates the city will have to spend upwards of $510 million to build and upgrade the dikes and seawalls — plus billions more to buy the land to put them on — over the next century.
“What’s under threat in Vancouver is a lot of our identity; our beaches, our seawall ... this is what makes Vancouver such a livable place,” Yan said. “We just need to look at Granville Island and its exposure to sea level rise and what may be required to defend it.”
"Rising sea levels" at Vancouver - really? "Rising" means now and in the recent past, right?


Lower now than in the mid-1980s is rising?

Saturday, 25 August 2012

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).

Thursday, 9 August 2012

"Diseased trees new source of climate gas" - really?

Sometimes, I read of what's hailed as "ground-breaking" research and chuckle to myself. In this case, I laughed at loud. Eureka! Science News has the breathtaking details -
Diseased trees in forests may be a significant new source of methane that causes climate change, according to researchers at the Yale School of Forestry & Environmental Studies in Geophysical Research Letters. Sixty trees sampled at Yale Myers Forest in northeastern Connecticut contained concentrations of methane that were as high as 80,000 times ambient levels. Normal air concentrations are less than 2 parts per million, but the Yale researchers found average levels of 15,000 parts per million inside trees.
Really? Decaying plant matter produces methane in the absence of oxygen? You could have knocked me over with an anaerobic digester. That page I linked to says
Farms and ranches can use anaerobic digesters—also known as biodigesters—to recover methane (biogas) from animal manure for producing electricity, heat, and hot water. Anaerobic digesters not only reduce energy costs but also methane emissions, which contribute to global warming.
It's referring to animal manure produced on farms and ranches, but it's well known that decaying plant matter produces methane rather than carbon dioxide when there's too little (or no) oxygen to add the "dioxide" part of the CO2. It's the reason methane bubbles to the surface from the bottom of pools and lakes. It's the reason that peatlands produce methane from thick and airless deposits below the surface. It's the reason the methane clathrates form layers in the sea-bed, much feared by some alarmists as a vast source of one of their bogey-man greenhouse gases.
"These are flammable concentrations," said Kristofer Covey, the study's lead author and a Ph.D. candidate at Yale. "Because the conditions thought to be driving this process are common throughout the world's forests, we believe we have found a globally significant new source of this potent greenhouse gas."
"New source"? A search on Google for rotting trees methane garners 3,290,000 results, most of which are relevant in identifying rotting vegetation, especially trees, as a significant global source of methane.
"No one until now has linked the idea that fungal rot of timber trees, a production problem in commercial forestry, might also present a problem for greenhouse gas and climate change mitigation," said Mark Bradford, a co-author and Assistant Professor of Terrestrial Ecosystem Ecology at F&ES.
""No one until now..." says Mark Bradford? People like Messrs Bradford & Covey really need to get out more, and when they are in, read more.

Tuesday, 7 August 2012

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.