APOD: Global Warming Predictions (2009 April 21)

[Chris Peterson]

Well there's this:

And ...[sea level]... has been rising faster in the mid-Atlantic because the land here is sinking.

Yeah, there is that. Parts of the Earth are still rebounding from the loss of glacial weight at the end of the last ice age, too. Local apparent sea level can be affected by either the actual rise or fall of water (as in the North Atlantic example), or by the rise and fall of the land itself.

However, "sea level" is measured against a static reference, usually a mathematical geoid modeling the shape of the Earth. Changes in sea level can occur against this reference from a number of causes, and can be different in different areas (that is, there is no single "sea level"). Changes in coastal land elevation create an apparent change in sea level, but I don't think it would be called a sea level change.

[StACase]

Well there's this:

And ...[sea level]... has been rising faster in the mid-Atlantic because the land here is sinking.

Yeah, there is that. Parts of the Earth are still rebounding from the loss of glacial weight at the end of the last ice age, too. Local apparent sea level can be affected by either the actual rise or fall of water (as in the North Atlantic example), or by the rise and fall of the land itself.

However, "sea level" is measured against a static reference, usually a mathematical geoid modeling the shape of the Earth. Changes in sea level can occur against this reference from a number of causes, and can be different in different areas (that is, there is no single "sea level"). Changes in coastal land elevation create an apparent change in sea level, but I don't think it would be called a sea level change.

I didn't make my point clear, if you go back to the April 23rd post by BMAONE23 there's a link to a Reuters article claiming that "Greenland ice could fuel severe U.S. sea level rise" in other words, "Global Warming". Now I find out that it's not "Global Warming" but rather the consequences brought about by the last ice age. That's a lot easier to accept and understand than believing that meltwater from Greenland will pile up unevenly in defiance of what I learned in the sixth grade about water seeking its own level.

[Chris Peterson]

I didn't make my point clear, if you go back to the April 23rd post by BMAONE23 there's a link to a Reuters article claiming that "Greenland ice could fuel severe U.S. sea level rise" in other words, "Global Warming". Now I find out that it's not "Global Warming" but rather the consequences brought about by the last ice age. That's a lot easier to accept and understand than believing that meltwater from Greenland will pile up unevenly in defiance of what I learned in the sixth grade about water seeking its own level.

In that case you are mistaken. The article in question (reporting on this) did not have anything to do with changes in land level because of mass shifting. It specifically addresses local changes in sea level because of changes in ocean currents. Such changes in current flow allow more water to pile up in the North Atlantic, particularly along North American shorelines.

There is nothing remotely controversial about the fact that sea levels are above or below the mean in different places because of currents, winds, and tidal effects. The only thing that is subject to question in this study is how accurately the model predicts the behavior of Atlantic currents in response to glacial melting. If the currents shift as predicted, there's really no doubt the sea level changes will follow. That's deterministic.

[gpobserver]

http://wattsupwiththat.com/2009/06/12/s ... #more-8407

[Chris Peterson]

I just ran across another sea level factor I was unaware of- demonstrating just how complicated this whole matter really is. In a May 15 paper and Perspective column (ref) about the potential effects on sea level as a result of changes in the West Antarctic Ice Sheet, it is pointed out that that an estimated 3.2 m rise in global sea level will induce an additional 0.4 m rise around North America and the southern Indian Ocean because of changes in Earth's gravity field and moment of inertia. The shift of mass from Antarctica into the oceans (1.8e6 gigatons) moves the Earth's spin axis and changes the centrifugal moments operating on the oceans, causing local shifts away from the gravitic isopotential. Greenland, which is also losing mass, can produce the same effect with half the WAIS mass loss because of its lower latitude.

This makes perfect sense, but is something I haven't seen described before.

[BMAONE23]

There is also differences in Tidal differentials depending on latitude. For example, at the mouth of Pensacola Bay, Pensacola, Florida; the tidal differential is only around 2 feet. The tidal differential at Tomales Bay, California is over 7 feet.
Over at Cape Cod / Plymouth it ranges up to 13'. And the largest recorded tidal differential which is at the Bay of Fundy up by Nova Scotia ranges up to 56 feet

[The Code]

Did anybody mention re-distribution of Mass? Changing the dynamic movement of plate tectonics? More water more bulge? more quakes.

Mark

[Chris Peterson]

Did anybody mention re-distribution of Mass? Changing the dynamic movement of plate tectonics? More water more bulge? more quakes.

The correlation between water mass (with tide) and earthquakes along coastal faults is very weak. Since the projected sea level increases are on the same order as tides, that suggests that the impact on tectonics and earthquakes would be minor.

[The Code]

The correlation between water mass (with tide) and earthquakes along coastal faults is very weak. Since the projected sea level increases are on the same order as tides, that suggests that the impact on tectonics and earthquakes would be minor.

Can't agree with that Mucker... The absence of 2 miles of ice does have an impact. its been proven.. Now take the ice from both polls..or lets say take the weight from them polls. The iner-mantel will move for the loss of pressure. and the rest because of this.

Mark

[Chris Peterson]

Can't agree with that Mucker... The absence of 2 miles of ice does have an impact. its been proven.. Now take the ice from both polls..or lets say take the weight from them polls. The iner-mantel will move for the loss of pressure. and the rest because of this.

Even under the worst case warming scenarios, it would take centuries or millennia to melt away the complete Antarctic ice pack. That's not really a concern. The issue here has to do with the instability of the West Antarctic Ice Sheet. This involves much less ice finding its way back into the oceans (although still plenty to muck around with sea levels).

The loss of mass in Antarctica might have measurable seismic effects, but I don't see it having major consequences. The WAIS subject to disintegration represents less than 10% of the Antarctic ice volume. This ice mass has little impact on the Antarctic plate as a whole, but compresses the center of the plate by 500-1000 meters. This is plastic deformation, and even if the entire ice pack were to disappear, the surface would simply rise slowly. The plate edges- where you have active seismicity- won't even know that the interior conditions have changed.

Northern North America is still rising because of the loss of glacial mass 12,000 years ago, and there's no evidence that is contributing to modern seismic activity.

[gpobserver]

http://wattsupwiththat.com/2009/06/12/c ... #more-8422

[gpobserver]

http://wattsupwiththat.com/2009/06/13/s ... #more-8478

[BMAONE23]

http://wattsupwiththat.com/2009/06/13/s ... #more-8478

I am presuming that the reason of your post is to present the sunspot data from cycle 10 in 1850's through the beginning of cycle 24 in 2008.
Looking at this particular chart
http://wattsupwiththat.files.wordpress. ... e_fig2.png
the data indicates a rather DEEP MINIMUM (relatively quiet solar period) between 1860 and 1910 and a downword trend from 1962 to 1998.
Neither of these trends are reflected well in the temperature chart attached below from WIKI.

In fact, the drop in solar activity from cycle 11 in 1866 to the low point of cycle 12 in 1878 doesn't seem to produce the same temperature drop as seen over the last 3 years as we entered the current solar minimum and solar activity low point (even though the drop in activity over cycle 12 was twice that entering cycle 24). In fact, the temperature increased over that period from 1860 to 1880 some .6dC as solar activity dropped from solar max of 400 spotless days in cycle 11 to over 1050 spotless days in cycle 12. This reaction seems to go counter to your supported theory of decreased solar activity equating to lowering temperatures due to increasing cosmic ray activity brought on by the said decreased solar activity. Then the other negative reaction to the solar activity theory occured from the 1960's to 1998. As solar activity gradually decreased in the solar cycles 20, 21 ,22, & 23, temperatures dramatically increased by >1 full degree C. If the solar activity were driving temperatures, Why do the temperatures not react proportionally to the solar activity decrease?

Edited to add link to reference to temperature chart as stated from WIKI for GP

[gpobserver]

Dear Sir,

I would greatly appreciate it if you could provide the source for the temperature record that you have cited so that I might knowledgeably craft a reply.

Thank you very much.

Best regards,
- Roy Tucker

[BMAONE23]

GP
Try the WIKI hyperlink now reactivated

[gpobserver]

This might be one of those issues where we're not going to agree on very much. The graphic you referenced was developed from instrumental temperature records involving weather monitoring networks such as the USHCN, NOAA, etc. Unfortunately, this record is possibly severely compromised by poor instrument siting and controls. Please see http://www.surfacestations.org/ for more information. I have been using the UAH and RSS satellite records because of the questions regarding the surface station data. We need to agree on what temperature record we can use before we continue with the solar influence discussion.

Best regards,
- Roy Tucker

[BMAONE23]

Try these

[gpobserver]

Try these

I'm afraid we'd have to spend some time on these temperature records and we'd still probably not agree. The US weather station network is supposed to be one of the better ones worldwide but its flaws are being revealed. 'Urban heat island' effect is one thing but having temperature recording instruments next to a blacktop parking lot or an air conditioning compressor is a totally different thing.I could also comment on similar problems with Siberian weather stations and other places. The satellite record has the advantage of measuring worldwide temperatures with the same instruments. See for example http://www.drroyspencer.com/latest-global-temperatures/

The RSS temperatures webpage is at http://www.ssmi.com/msu/msu_data_descri ... ml#figures

Similar debates are involved with 'sea surface temperatures' as opposed to 'ocean heat content'. Unfortunately, the whole field has become so politicized that not only are some data products suppressed but some are alleged or have been demonstrated to have been 'fudged'. Even taking some particular dataset, one can come up with different numbers for 'trends' by judiciously selecting end-points for trendlines.

I'm not sure getting into a discussion of temperature records will really lead to any agreements. For example, someone could assert that they measured the temperature someplace for many years using the same mercury thermometer. That sounds like it ought to be a very consistent data set. A critic might then ask if the thermometer was shielded from sunlight or the clear sky. Sunlight could warm it by radiation or exposure to the sky could cool it (if you have ever experimented with an infrared thermometer, you know that the clear sky is very cold when the humidity is low, like here in Tucson). There might then be questions raised about the accuracy of the measurements based upon the reflectivity of the thermometer or its infrared emissivity. If shielded in some enclosure, there might be questions raised about whether the enclosure was painted with white latex paint or whitewash. Was the observer standing upwind or downwind of the thermometer during the measurement? Was the sky clear or cloudy? If any detail was not recorded then it might be claimed that the whole data set is 'unreliable'. The assessment might be valid or not. That leads to an entirely different discussion. Gee whiz! I'm not sure I really want to get into this.

[BMAONE23]

Try these

I'm afraid we'd have to spend some time on these temperature records and we'd still probably not agree. The US weather station network is supposed to be one of the better ones worldwide but its flaws are being revealed. 'Urban heat island' effect is one thing but having temperature recording instruments next to a blacktop parking lot or an air conditioning compressor is a totally different thing.I could also comment on similar problems with Siberian weather stations and other places. The satellite record has the advantage of measuring worldwide temperatures with the same instruments. See for example http://www.drroyspencer.com/latest-global-temperatures/

I can see where temperatures in city areas might be locally affected by the Heat Island Effect you mention. This effect could affect local weather sensing stations and Temperature data gathered therefrom. But the first descrepancy between temperature data in the temperature chart from WIKI and the Solar Activity data in the solar cycle chart you supplied would not be nerely as influenced by Heat Island Effect in 1860 as there were little to no paved roads or "Black Top" parking lots in existance at that time. Roads that were paved were usually light colored cobble stone roads with reflectance and night time radiance similar to bare ground. Buildings were significantly smaller with less roof surface and there were many more natural tree covered areas (forests opposed to landscaped tree covered areas) with dirt roads and paths. This more natural setting would have little to no Heat Island effect.


What is your opinion on this and the Milankovitch cycles?

[BMAONE23]

Excerpt:
"Beijing/Nairobi, 13 November 2008 - Cities from Beijing to New Delhi are getting darker, glaciers in ranges like the Himalayas are melting faster and weather systems becoming more extreme, in part, due to the combined effects of human-made Atmospheric Brown Clouds (ABCs) and greenhouse gases in the atmosphere.


The brown clouds, the result of burning of fossil fuels and biomass, are in some cases and regions aggravating the impacts of greenhouse gas-induced climate change, says the report.


This is because ABCs lead to the formation of particles like black carbon and soot that absorb sunlight and heat the air; and gases such as ozone which enhance the greenhouse effect of CO2."

[gpobserver]

Yet another example:

http://wattsupwiththat.com/2009/06/16/h ... #more-8542

[gpobserver]

What is your opinion on this and the Milankovitch cycles?

Thank you for pointing me to that article. It pretty nicely summarizes the various influences on natural climate change that I have encountered in many different journals, textbooks, and classes over the years. An article that I read in the past year indicated that the Milankovitch hypothesis was no longer as popular as it once was. I regret I forget the reasons at the moment. Another thing that physicists have suggested as possibly important is "stochastic resonance". See, for example: http://physics.aps.org/articles/v2/23

It appears from the geological record that the earth has two relatively stable climate states, 'ice age' and interglacial. Perturbations from orbital mechanics, volcanoes, solar activity, and who knows what else can act upon the non-linear climate system to perhaps increase the ease with which the system may transition from one state to the other in accordance with this principle of stochastic resonance. It's somewhat amazing to me that after all of this time and effort trying to understand the causes of ice ages, we still aren't sure.

One interesting speculation that I encountered suggested that if the warm water of the Gulf Stream began to penetrate into the Arctic Ocean, it would greatly reduce sea ice and there would be increased evaporation. This water vapor would increase snowfall and earth's albedo, reducing temperatures further. As sea level falls, the Arctic Ocean would be even more restricted and the evaporation would draw in more warm water from the north Atlantic, perpetuating the process. It's a paradoxical picture, continents clad in thick ice while the Arctic Ocean is open water.

[BMAONE23]

(snip)

One interesting speculation that I encountered suggested that if the warm water of the Gulf Stream began to penetrate into the Arctic Ocean, it would greatly reduce sea ice and there would be increased evaporation. This water vapor would increase snowfall and earth's albedo, reducing temperatures further. As sea level falls, the Arctic Ocean would be even more restricted and the evaporation would draw in more warm water from the north Atlantic, perpetuating the process. It's a paradoxical picture, continents clad in thick ice while the Arctic Ocean is open water.

I believe that the Arctic Ice is in fact the buffer against this particular occurance. That the Ice both on Greenland and in the Arctic Ocean act to stabilize the Thermohaline Circulation's northern most progression. It could also act to the opposite by pouring vast ammounts of cold, fresh meltwater into the Arctic Ocean and forcing the Warmer Gulf Stream waters to recirculate at a lower latitude, thereby cooling the northern latitudes and bringing about an Ice Age.

Arctic region melts...Greenland Warms...Greenland Ice pack melts...Thermohaline Circulation Warm water currents are forced to recycle south at lower latitudes...Northern latitudes cool without warm ocean influence...Storm activity increases in strength and frequency...Ice age begins...Ice rebuilds...Arctic cools and Greenland freezes over as Ice sheets progress.

[aristarchusinexile]

Please don't anyone get all excited about my posting today .. I'm here for a good time, not a long time. I read an article about the 'computer models' involving arctic icemelt, and in the last decade they've ranged from an ice-free summer arctic (spelling corrected) in 100 years to the most radical and most recent an ice-free summer arctic by 2013 .. and it looks like the 2013 model will win out, and to me this says a lot about computer modeling in general, which brings us back to the model I made of the anti-gravity bubble expansion universe, of course, not using a computer, just some old sponges and my granddaughter's sparkly paints, but you know, it's radical and right, so just believe it you dunderheads, and I say that with Spirit!

[gpobserver]

Sweet! Nothing like data and observations.

http://science.nasa.gov/headlines/y2009 ... stream.htm