Yes. For the temperature ranges found in the upper levels of the ocean, water will expand as the temperature increases.
I’m not trying to offer anthing controversial, but on the way home tonight, listening to NPR, you might want to visit Southern Florida pretty soon.
Well, the rate is tiny. At most 3mm a year, or about a inch a decade. (Some projected rates are higher, some lower).
You would not notice 3mm. You would not notice an inch over a decade. They are trying to scare dudes.It is a very real problem*, but a problem that will more affect our grandkids than us.
- although figures very wildly.
Cite?
Seems to me, what with the ignorance being flaunted around in this very thread, that informing dudes is the simplest hypothesis consistent with the facts.
Were you personally aware of the effect of water temperature on sea level, or is the info in this thread new to you? Does such thermal expansion frighten you?
When you make relieving ignorance equatable to scaring dudes, you become a proponent of ignorance yourself. Surely that’s not your intent here at a place that’s been “fighting ignorance since 1973” is it, DrDeth?
[Moderating]
Once again, let’s keep this factual. Comments like this are out of place in this discussion.
Colibri
General Questions Moderator
I mentioned nothing at all about the effect of water temperature,
you’re apparently confusing me with another poster. I just stated what the rate of rise was, and thus that it wasn’t a big problem in the near future, nor is it something that would be noticeable to a casual observer.
Or perhaps you disagree with my figures?
The Australian Bureau of Meteorology has on its site a PDF of Annual Sea Level Data Summary Report for the The Australian Baseline Sea Level Monitoring Project.
It states in part:
The IPCC AR4, 2007 estimates that global average eustatic sea level rise over the last century was 1.7 ± 0.5 mm/yr. From 1961 to 2003, the average rate of sea level rise is estimated as 1.8 ± 0.5 mm/yr. IPCC AR4, 2007 also recognises that sea level records contain a considerable amount of inter-annual and decadal variability. For instance, the average rate of sea level rise for the decadal period 1993 – 2003 based on satellite altimetry is 3.1 ± 0.7 mm/yr. Studies have shown that comparably large rates of average sea level rise have been observed in previous decades.
Note both the margin of error and the last sentence.
Elsewhere it notes:
Sea level and climate can vary about a long-term climatological mean from one decade to the next. The project to date is yet to span two complete decades, so it is important to recognise that the sea level change observed over this time is largely a measure of decadal variability. Continued monitoring is needed to quantify the longer-term trend that is associated with climate change.
and also:
Although simulations of recent sea level rise (eg 1993 to 2003) are in reasonable agreement with observations, longer-term sea level rise has not been satisfactorily modelled. This implies a deficiency in the current understanding, which is partly related to the poor global coverage of high quality historical tide gauge records and the uncertainty in the corrections for land motions. The high-accuracy sea level stations installed for the ABSLMP will help address these issues in future.
Your selected quotes emphasize the current uncertainty in making precise estimates of the amounts of sea level rise due to long-term climate change, which is a fair point.
However, I think they somewhat misleadingly omit the report’s overall concurrence with the mainstream hypothesis that there is a long-term rising trend in average sea level, due to global warming:
Yes, it’s true that the precise amount of sea level rise to date that can be unambiguously attributed to long-term anthropogenic climate change cannot currently be determined, as it’s pretty small and gets swamped in shorter-term fluctuations.
However, the basic physics underlying the mainstream hypothesis of a predicted long-term sea-level rise due to anthropogenic climate change is AFAICT fairly uncontroversial: namely,
-
significant anthropogenic increases in greenhouse gases warm the atmosphere;
-
the warmer atmosphere warms the ocean;
-
the warmer ocean water expands, causing average sea levels to rise. (Land-based ice melting plays a part in the rise as well, but the thermal expansion is the biggest factor.)
So if the OP is trying to find out what the scientific evidence is for average global sea levels having already detectably risen specifically as a result of anthropogenic global warming, the answer AFAIK is, “not much”.
But if the OP wants to know what the scientific evidence is for predicting that average global sea levels will continue to rise by a significant amount over the next century specifically as a result of anthropogenic global warming, then AFAIK the answer is, “pretty good”.
What % of all greenhouse gases are anthropogenic? Not just CO2, include water vapor, etc.
[Moderating]
Once again, I would rather this not develop into a general debate about global warming. As anyone familiar with the debate knows, while an important greenhouse gas, water does not persist in the atmosphere the same way as CO2 and other greenhouse gas does, and is thus not equivalent. I regard your raising this issue as an attempt to sidetrack the thread. If you want to discuss whether global warming is or is not occurring, do so in one of the threads in GD.
Colibri
General Questions Moderator
It’s not the rate that’s worrying; it’s the acceleration. Check out the Quirks & Quarks episode linked by another poster fur further explanation and discussion.
Some proponents of the Expanding Earth theory argue that midocean ridges “smoker vents” contribute to a rise in sea level:
*"The midocean LUVs vigorously extrude new basaltic seafloor and virgin new water via “black smoker” vents, plus an unknown, but prodigious, amount of other gases, minerals and heat as byproducts of the expansion process.
…
The LUVs are now the single greatest source of new water filling the expanding ocean basins, so research is needed to determine whether new ocean basin growth is keeping up with the increasing volume of new water. "*
(I don’t know what LUV stands for)
Individual components of sea level rise are provided as a table within the latest IPCC report(AR4, 2007). Note that the most recent estimates for Greenland Ice Sheet loss (1995-2007) exceed that in the IPCC report by a factor of c. 3.5.
LUV stands for linear underwater volcano, a term used by the vanishingly small number of eccentric theorists who still advocate the expanding Earth hypothesis. The term fissure volcano is used by ordinary geologists in describing these features. The expanding Earth hypothesis has no serious scientific support or geological evidence in its favour. Not only is it discredited, but if the Earth were supposedly expanding this would increase the volume of the ocean basins, leading to a relative sea level fall. Invoking it as an explanation is nonsensical.