Topic: Global Warming

[Astronuc]

North Pole [Arctic] mussels a sign of global warming - Sept 18, 2004

Mussels have been found growing on the seabed just 1,300 kilometres from the North Pole in a likely sign of global warming, scientists said.

The blue mussels, which normally favour warmer waters like off France or the eastern United States, were discovered last month off Norway's Svalbard archipelago in waters that are covered with ice most of the year.

"The climate is changing fast," said Geir Johnsen, a professor at the Norwegian University for Science and Technology who was among experts who found the bivalves.

Molluscs were a "very good indicator that the climate is warming," he said.

"It seems like the mussels we found are two to three years old," he told Reuters.

Such shellfish have not been recorded off the islands since Viking times 1,000 years ago during another warm period.

UN scientists say the Arctic is now warming faster than any other region because of human emissions of carbon dioxide and other greenhouse gases released from burning fossil fuels in cars, factories and power plants.

As the white ice and snow melts, it exposes darker ground or water that soaks up heat and so accelerates warming compared to regions further south.

By comparison, ice in Antarctica is thicker and acts as a deep freeze resisting global warming.

Inuit peoples in Canada, for instance, are seeing robins for the first time and hunters are falling through previously solid sea ice.

--Reuters

[Orstio]

Such shellfish have not been recorded off the islands since Viking times 1,000 years ago during another warm period.

UN scientists say the Arctic is now warming faster than any other region because of human emissions of carbon dioxide and other greenhouse gases released from burning fossil fuels in cars, factories and power plants.

I find those two statements, right next to each other, very interesting.  I suppose that the shellfish in the Viking times, and that warm period, were also indications of human emissions of carbon dioxide and other greenhouse gases released from burning fossil fuels in cars, factories, and power plants?  Or is there perhaps an explanation for both warming periods, that really has very little to do with humans?

[Astronuc]

Re: The other warming period.

During a recent trip to the SW US, I visited some ruins of indigenous peoples.  They ultimately abandoned their village which was located in a canyon, which in the distant past had a river running throught it.  Now there is little or no water, except for flash floods from the runoff in the mountains.

I would have to check the date when the ruins were abandoned, but it was on the order of 800-1000 years ago.

I surmise that the rains stopped or were significantly reduced and thus the crops failed and the wildlife migrated elsewhere or starved, so the people left.

What caused the warming, of that I am not sure.

[Orstio]

I just find it interesting that any and all global climate change is immediately attributed to emissions caused by humans, when there is overwhelming prehistoric evidence to the contrary.  The temperature of the Earth has fluctuated far more in the distant past than it has in the (very short) period of time that we have been recording global weather.  It seems that our lack of data concerning climate change is being used as evidence that we are having the most profound effect on our global climate of all factors, when in fact we do not even know what all the factors affecting global climate are.  Remember only a few years ago when El Nino was discovered?

Far more cataclysmic events occur that affect global climate:

http://news.nationalgeographic.com/news/2003/03/0317_030317_iceshelf.html

And, from that article:

According to a study last year, the Antarctic is the only continent in the world that is currently growing cooler. Researchers discovered that temperatures on the icy continent actually decreased by 0.7° Celsius (1.8° Fahrenheit) per decade in the last 35 years.

http://www.co2science.org/journal/2001/v4n7c3.htm

From Christian Science Monitor (OK, not the best source, but it illustrates my point quite well):

http://www.csmonitor.com/2004/0318/p13s01-sten.html

"In the absence of better knowledge, we have to assume that humans are making abrupt climate change more likely - not because humans are worse than nature, it's just because we're changing the system," says Richard Alley, a Penn State University paleoclimatologist.

Now, for scientific method, "the absence of better knowledge" would mean no asssumption of anything.  If you have no data, you make no assumptions.  Yet, as Richard Alley states, the assumption is that humans are having a profound effect, because there is no knowledge to say one way or the other.  The absence of data is used as evidence.  That's really bad science, as far as I am concerned.

[Astronuc]

It is the statement ,"the absence of better knowledge", that is a bit troubling.  What does that mean or imply - that we lack complete knowledge, lack a lot, or lack a little?  Certainly we have only really started measuring global temperatures trends in the past few decades, and before that, we must rely on written records only going back no more than 150 to 200 years, and those are in a few places where thermometers were available.  Trying to extrapolate back over millenia is speculation.

The next best thing for long term climate assessment is archeological or paleoclimatology which deals with collecting glacial ice in remote areas, where the ice is more or less as it was hundreds or thousands of years ago.  However, although this might indicate what happened, it does not necessarily lead to why or how.

And then there is the statement about "abrupt change" - what does it mean?  How abrupt?  10 years, 100 years, 1000 years (slow by human life times, but short in terms of geological periods).

[cassiopeiae]

And then there is the statement about "abrupt change" - what does it mean?  How abrupt?  10 years, 100 years, 1000 years (slow by human life times, but short in terms of geological periods).

It seems like it was less of an "abrupt change" and more of an "abrupt acknowledgement".  If there is a cycle to climate change, which has been speculated, it may take thousands of years for any noticable change to occur.

I have problems with the "absence of better knowledge" statement too.  In one way, we can assume that humans and our pollutants are the cause, but on the other, the oceans are heating themselves, emitting more methane, experiencing more eruptions.

As of late it is quite obvious to me the earth is having a fit...volcanic acitivity, earthquakes, hurricanes, flooding...

I had read somewhere that the magnetic field around the earth has been depleting steadily for the last 20 years or so, which would decrease the protection we normally have from solar emissions...would this effect the climate in any way?

[Orstio]

I had read somewhere that the magnetic field around the earth has been depleting steadily for the last 20 years or so, which would decrease the protection we normally have from solar emissions...would this effect the climate in any way?

Here is a nice beginner's tutorial of how the magnetosphere works:

http://science.nasa.gov/ssl/pad/sppb/edu/magnetosphere/

I'll get more info, so you'll have a better understanding of the possible effects of things like pole flips, and double solar maximums (we had a solar max in 2000, and another in 2002).  Solar max usually only happens once every 11 years, in time with the Sun's polar flip. http://science.nasa.gov/headlines/y2002/18jan_solarback.htm

[Orstio]

http://ssdoo.gsfc.nasa.gov/education/lectures/magnetosphere/index.html

Solar activity may affect both short-term weather patterns and long-term climate trends. Changes in the magnetosphere seem to be transmitted to the lower atmosphere where they may influence the circulation of air masses. If we can discover the physical links between these two regions of our environment that trigger weather and climate changes, we can better predict and prepare for our weather. At this time, it is believed that energy from the solar wind transmitted through the magnetosphere has only a minor effort on our climate, however, a significant amount of research needs to be completed before a better understanding is obtained.

It is important to note that magnetic storms have produced other noticeable effects on the Earth, such as:

• Current surges in power lines, causing flickering lights and black-outs resulting in millions of dollars worth of damage
• Static interference and interrupted transmission of radio, television, telephone, and telegraph signals
• Erratic behavior of air and marine navigation instruments
• Disruption of defense communications, such as the Early Warning radar system
• Alterations in the atmospheric ozone layer that absorbs harmful ultra-violet radiation from the Sun

[Orstio]

BTW:  The northern migration of mussels can signify things other than global warming.

For example:  Mussels are a large part of the diet of the walrus.  Changes in walrus population and distribution can affect the population and distribution of mussels in the northern oceans.

http://www.seaworld.org/infobooks/Walrus/habdiswal.html

By the early 1980s, walruses appeared leaner, they increased their consumption of alternate foods such as fishes, natural mortality increased, and birth rates decreased. This evidence supports the theory that the Pacific walrus population may have approached the carrying capacity of its environment.

As the Pacific walrus population has grown, annual subsistence catches by indigenous Arctic peoples has increased. Some scientists predict that, without adequate long-term management, natural and human-related mortality factors will rapidly reduce the population once more.

[Astronuc]

Here is some fuel for the fire -

The Global Warming Debate
By James Hansen
http://www.giss.nasa.gov/edu/gwdebate/

Goddard Institute is affiliated with Columbia University, New York, NY.

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http://atoc.ucsd.edu/Explorations_f98/Atoc.html

Acoustic Thermometry of Ocean Climate
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Conservative Counter Point - from NATIONAL CENTER FOR POLICY ANALYSIS
http://www.ncpa.org/ba/ba230.html
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Climate Observations Substantiate Global Warming Models
from Chemical & Engineering News, American Chemical Society, November 27, 1995
http://pubs.acs.org/hotartcl/cenear/951127/pg1.html

[Astronuc]

Here is one of the concerns regarding the evidence -

the graph ostensibly represents a trend in global mean 'air' temperature.  I just don't know how the global mean is calculated nor the basis of the population.

I have a hard time believe that back in the 1880's to 1900's, people were measuring temperature reliably around the globe.  What stations were used, and are they the same today?

Are the data truly representative of a 'global' base?

It is entirely possible that the earth is warming, and certainly CO2 could be a factor, as well as soot.  But I would like to be sure of the integrity of the scientific method.

Also, I would like to see less air pollution.

[cassiopeiae]

Relating to the Earth's pole shift and global warming...sorry, this is on, but also off topic....

How can it be said that the pole shift will not effect the Earth, when it is thought (or proven, I do not know) that the magnetic field surrounding the Earth depletes prior to the pole shift?

The articles I have read about the magnetosphere (thanks Orstio ;D) clearly state that solar activity "may influence both short weather trends and long term climate changes" thus resulting in changes in the environment either long or short term.  At the same time, it seems they (scientists) are saying that this only "has a minor effect" on the climate.  Would it not pertain to exactly how much the magnetic field has depleted? 

By the time the poles actually shift (which is estimated to be around 1500 years by some by measuring the rate of depletion) the Earth will have 0 magnetic field...would this not cause more intensity??  Logically I would say yes, and I can't figure out why scientists are saying that nothing will happen to the environment, nor how science can say the magnetosphere only effects "minor" climate issues.

From the previous articles earlier posted, there has been much evidence of climate change in the past, and logically, it cannot be contributed to purely human contributions...So...what does all of this say logically? 

To me it says there are many different circumstances which are being noticed in our time, most of which are out of our control, though we do contribute to and speed up the process, even if only a bit...and, that science is not sure about much of anything when it comes to the visible changes in the Earth's climate or environment....(it really erks me to come to that conclusion...there is a pattern to the madness, i think, or hope anyway)

[Orstio]

By the time the poles actually shift (which is estimated to be around 1500 years by some by measuring the rate of depletion) the Earth will have 0 magnetic field...

That's not exactly the case.  The Earth's magnetic field will most likely do something similar to what the Sun's does.  It doesn't vanish, and then restart, it creates a bunch of smaller fields all over the globe, which is almost as protective as the single field.  It's not as strong as the single magnetic field, but it's enough that it would protect us.

http://www.newscientist.com/news/news.jsp?id=ns99994985

The entire process of the pole flip is estimated to take centuries.  But, it is a fairly regular occurance (by geological time) for the Earth, and there is no evidence to support any effects like mass extinctions or radical climate change caused by the flip.  It's not as if the poles haven't flipped before:  they just have not done so within our recorded history.

[cassiopeiae]

It doesn't vanish, and then restart, it creates a bunch of smaller fields all over the globe, which is almost as protective as the single field.

I remember reading this now, but then the question arises, how can a depletion be measured then, if it is only re-distributing?

...and there is no evidence to support any effects like mass extinctions or radical climate change caused by the flip.  It's not as if the poles haven't flipped before:  they just have not done so within our recorded history.

I don't believe there would be a "radical" change in an instant, but over time, as the articles suggest, depletion "could" have long-term climate effects.  I take this to mean that over the centuries that are estimated for the pole shift the the climate would be effected, which actually could (over a period of time) cause some species to become extinct.

My whole point was, with regards to global warming, the noted depletion of the magnetic field could be another cause to the weather patterns we are noticing, which may lead up to the climate change scientists are expecting and warning about.  I would think that this would cause a direct change in atmospheric temperature.

On the side of the Earth heating...
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http://www.gsfc.nasa.gov/topstory/2004/0415gyre.html
Excerpt...
The current, known as the sub polar gyre, has weakened in the past in connection with certain phases of a large-scale atmospheric pressure system known as the North Atlantic Oscillation (NAO). But the NAO has switched phases twice in the 1990s, while the subpolar gyre current has continued to weaken. Whether the trend is part of a natural cycle or the result of other factors related to global warming is unknown.

"It is a signal of large climate variability in the high latitudes," Hakkinen said. "If this trend continues, it could indicate reorganization of the ocean climate system, perhaps with changes in the whole climate system, but we need another good five to 10 years to say something like that is happening." Rhines said, "The subpolar zone of the Earth is a key site for studying the climate. It's like Grand Central Station there, as many of the major ocean water masses pass through from the Arctic and from warmer latitudes. They are modified in this basin. Computer models have shown the slowing and speeding up of the subpolar gyre can influence the entire ocean circulation system."
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http://www.newscientist.com/news/news.jsp?id=ns99994639
Noxious undersea eruptions killing billions of fish
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Another good resource...
http://www.co2science.com/subject/o/subject_o.htm

[remcook]

hmmm..nice discussion!
if you look at very long timescales we do actually live in a cool period. On the other hand, there may be an ice age coming.
climate is still far from understood.