People send me stuff. You may recall this story from last week that raised a number of eyebrows due to the claims made within it by author William Hay. Dave Burton decided to take him to task. So far no response.
From: David Burton
To: William W. Hay
Cc: Ted Carmichael; Anthony Watts
Sent: Sun, November 4, 2012 6:25:15 AM
Subject: Re: Could Estimates of the Rate of Future Sea-Level Rise Be Too Low?
Hello, Dr. Hay,
I hope you’re enjoying the “Old North State!” Did you receive my previous email (below, w/ one typographical correction)?
On Fri, Nov 2, 2012 at 5:55 AM, David Burton wrote:
Dear Dr. Hay,The abstract of your Sunday, 11/4/2012 presentation, “Could Estimates of the Rate of Future Sea-Level Rise Be Too Low?” has attracted considerable attention at WUWT:
Perhaps you’d like to weigh in there.
The 2nd sentence of your abstract is the most startling for its inconsistency with the measurements with which I’m familiar:
“Current sea-level rise measurements track or exceed the maximum rate of rise proposed by the IPCC and suggest a rise of 1 meter or more by the end of the century.”
One meter of sea-level rise over the next 87.2 years would be an average rate of of 11.5 mm/year. But actual sea-level measurements show that it is rising at a tiny fraction of that rate, and measurements at most locations show no sign of acceleration in the last 80+ years.
This is one of the longest and most complete records of sea-level in the world, and it fortuitously happens to be at a location where there is little or no PGR:
The lack of acceleration in rate of sea-level rise is obvious. So why do you say that these current measurements suggest an average rate of eight times that for the next 87 years??
A few other things in your abstract also puzzled me:
“…changes in the volume of the ocean basins… can be neglected for projections of sea-level change over the next few centuries.”
The main contributor to changes in the volume of the ocean basins is thought to be GIA: the presumed sinking of the ocean floor due to the addition of meltwater from ice sheets circa 10K years ago. But GIA accounts for over 1/3 of the often-claimed 1.8 mm/year average rate of coastal sea-level rise (from tide gauges) over the last 100 years. That hardly seems negligible. Also, a 0.3 mm/yr GIA “fudge factor” to account for presumed post-glacial sinking of the ocean floor is usually added to satellite-measured rates of sea-level rise when they are reported. If “sea level” means the level of the surface of the sea, then adding that adjustment to measured numbers yields a quantity which can no longer be truthfully called “sea level,” but the addition inflates reported satellite-measured sea-level rise by more than 10%, so I don’t think that’s negligible.
Perhaps you meant, “changes in the volume of the ocean basins due to factors other than GIA?”
“…the location of atmospheric high and low pressure systems… [can not] be neglected for projections of sea-level change over the next few centuries.”
Is that a typographical error? Weather systems do move water around, but only over relatively short time time spans. For century-scale time-spans, that factor can be neglected.
“The Greenland ice sheet is melting, and the Antarctic beginning to melt, both at increasing rates.”
This seems to be based on outdated information. The latest ICEsat measurements indicate that Antarctica is gaining ice mass.
“The rise of ocean temperature has a major effect roughly equal to the input of glacial meltwaters”
Do you realize that sea-surface temperature changes do not affect coastal sea-level at all? (That’s one of the ways in which coastal tide gauge measurements differ from satellite altimeter measurements, and one of the reasons that it is always a mistake to conflate the two.) Gravity balances mass, not volume, so when ocean surface waters warm or cool, the resulting density changes have only local effects, rising or sinking in place, like icebergs. Only if there are density changes in the ocean depths can it affect coastal sea-levels, and no such changes are thus far in evidence.