"World’s 76 Best Tide Gauges
(100+ Years Of Data) Show
A Mean 0.34 mm/yr Rise,
‘Negligible’ Acceleration"
Boretti, 2019
NOTE:
An accurate determination
of sea level rise
acceleration trends
requires at least 100 years
of data due to the natural
(60- to 80-year) oscillations
that could bias the results
depending on the start
and end dates.
There are 88
world tide gauges
with a record length
of at least 100 years
in the psmsl.org data base.
Of those, 76 have
no data quality issues.
SUMMARY:
These results
undermine
the usual computer
model-based claims
that the world’s seas
are sharply rising
and accelerating
due to CO2-induced
global warming.
The average rate of rise
for these 76 global-scale
tide gauges is just
+0.337 millimeters
per year (mm/yr),
and the acceleration
is a “negligible”
+0.007 mm/yr².
Thus, the average rate
of sea level rise
for the world’s best
long-term-trend (LTT)
tide gauges amounts
to about +3½ centimeters
per century.
Boretti, 2019 says:
“All the long-term-trend (LTT)
tide gauges of the world
consistently show
a negligible acceleration
since the time they started
recording in the late 1800s
and early 1900s, much less
than the +0.022 mm/yr2.”
“Hence,
the state of the oceans
cannot be described
as sharply warming
and accelerating since 1870,
as there is yet no sign
of the climate models
predicted sharply warming
and accelerating sea level rise.”
DETAILS:
Further, the relatively
high (2 to 3 mm/yr)
local rates of sea level rise
in the studied region
( the Mexican Caribbean )
were determined to be
primarily associated with
land subsidence.
This affirms the conclusion
(Piecuch et al., 2018) that
geological processes,
or vertical land motions,
are more influential than
climate-related processes
in establishing local relative
sea level trends.
“Because of the well-known
multi-decadal natural oscillations
of periodicity up to quasi-60 years
(Chambers, Merrifield & Nerem, 2012;
Schlesinger & Ramankutty, 1994),
not less than 100 years
of continuous recording
in the same location and
without quality issues
are needed to compute
rates and accelerations
by linear and parabolic fittings.
However, not a single tide gauge
has been operational since 1870
in the southern hemisphere,
and very few tide gauges
have been operational
since 1870 in the
northern hemisphere.”
“If we now take a subset
of the 1269 tide gauge records
of www.psmsl.org,
requesting a range
of not less than 100 years,
there are 88 tide gauges
total around the world
satisfying this criterion.
If we neglect the tide gauges
having quality issues, such as
data originating from multiple
tide gauges, misaligned data,
significant gaps, there are then
76 tide gauges left.
These tide gauges have
an average rate of rise 0.337,
max. 6.660, min. -7.903 mm/yr.,
and an average acceleration
0.00700, max. 0.06090,
min. -0.05560 mm/yr².”
“Apart from land motions
of longer and wider scales,
it is however important
to measure the local
vertical motion of the land
in an absolute reference frame.
From GPS monitoring
of fixed domes nearby
the tide gauge,
the subsidence in Key West
is comparable to the relative
sea level rise.
In the nearby global
positioning system (GPS) dome
of CHIN, distance to tide gauge 400 m,
with data 2008.91 to 2018.99,
the subsidence is -3.017±2.256 mm/yr.
(Blewitt, Hammond, & Kreemer, 2018).
The relative sea level, rises here,
mostly because of the land sinks.
On a shorter,
but still long, time-frame,
Peltier (1986) calculated the
GIA subsidence
of the Atlantic margin
for the entire east coast
of the United States,
with specific for Florida
a subsidence rate
of about 1 mm/yr.”
