Climate change accelerating fast.

[BrianG]

.... Unfortunately, ice cores do present some difficulties and have limitations that scientists must overcome.

 

One major problem that has become more prevalent in recent years is summer melting of

the ice fields. Recent surveys of Greenland have shown large areas of summer melt in

southern Greenland, and recent visits to Peru’s Quelccaya ice cap have shown melt areas

where none existed only 25 years ago. The problem that melting presents is that the

melted water percolates down through the ice and can destroy the even layering that regular

snowfall produces. This makes accurate dating extremely difficult, and contaminates

many of the naturally deposited stable isotopes and other chemical constituents in the ice

with non-representative concentrations...

From: http://www.csa1.co.uk/discoveryguides/icecore/review.pdf page 9.

 

CraigD and I have been unable to find a name for this effect, I've decided to call it the "Ice Thermometer Bias".

[freeztar]

the past 400,000 years of ice core measurements don't show very much CO2, that could be a problem with the method.

 

Sorry, Brian, but this doesn't cut it here. Where are you getting your information from?

 

We have a rule that you must support your claims, for a reason. What is "very much"? What method are you referring to? Have you analysed ice cores? If not, who has? (that you are getting your numbers from)

 

If you can answer these questions, then edit your post to include the answers. (links please!)

[CraigD]

.... Unfortunately, ice cores do present some difficulties and have limitations that scientists must overcome.

One major problem that has become more prevalent in recent years is summer melting of the ice fields. Recent surveys of Greenland have shown large areas of summer melt in southern Greenland, and recent visits to Peru’s Quelccaya ice cap have shown melt areas where none existed only 25 years ago. The problem that melting presents is that the melted water percolates down through the ice and can destroy the even layering that regular snowfall produces. This makes accurate dating extremely difficult, and contaminates many of the naturally deposited stable isotopes and other chemical constituents in the ice with non-representative concentrations...

 

From:

http://www.csa1.co.uk/discoveryguides/icecore/review.pdf

page 9.

It’s important to read this quote carefully, and note that the “summer melting of the ice fields” problem is recent, appearing in ice sheets that previously never experienced significant melting only in the last 25 years, and also that it isn’t a problem at all sites, such as Vostok station.

 

While troubling because of the valuable data lost due to the percolation of melt water through the century or two of layered snow (firn) on the top of ice cores from affected sites, this is mitigated by there being direct, non-proxy measurements of many of the parameters for the lost data is a proxy for the last roughly century.

 

It’s also important not to overact to this or other technical difficulties and limitations of climate proxy measuring techniques such as ice cores by concluding that since these difficulties exist, conclusions such as the scientific consensus that recent (last 100 years) global warming is due primarily to increases in atmospheric [ce]CO2[/ce] due primarily to humans burning stuff are unsupported.

 

Finally, it’s important not to quote sources, especially secondary ones (writing that presents questions and conclusions based on data and analysis from primary sources), out of context. The paper by Christopher Readinger quoted above is strongly supportive of what it terms “the theory of global warming”. As your goal in all your posting at hypography appears to be to discredit this theory, the use of sources that support it to support your goal is confusing

CraigD and I have been unable to find a name for this effect, I've decided to call it the "Ice Thermometer Bias".

I recommend not using this phrase, because it’s poorly descriptive for several reasons, including but not limited to:

• Ice cores analysis isn’t very much like a thermometer, an instrument that measures temperature directly
  
• The term “ice thermometer” is already used, albeit infrequently, to refer to thermometers intended to read temperatures below 0 °C, such as those kept in freezers, and generically to refer to any thermometer used to measure the temperature of ice.
  
• “bias” is a term with a precise meaning in many scientific and humanities disciplines referring to the tendency of a given measurement to differ from an accurate measurement always in a particular way (eg: always too high or always too low). The phenomena involving ice cores we’ve been discussing results in the loss of data, not the skewing it in a predictable direction
  
• In the usage you intend, Brian, the phrase is arguable one of weasel words. The use of weasel words is discouraged at least informally by most forums, and formally by wikipedia.
  

Also, as I’ve stated before, there’s little use for a short phrase identifying a phenomena that’s not frequently mentioned, where a brief description of the phenomena requires only a little more text, and is unambiguous and free of the above and other potentials for confusion.

[BrianG]

It’s important to read this quote carefully, and note that the “summer melting of the ice fields” problem is recent, appearing in ice sheets that previously never experienced significant melting only in the last 25 years, and also that it isn’t a problem at all sites, such as Vostok station...

 

Can you support the claim that there's never been significant melting at Vostok?

 

My "Ice Thermometer Bias" Weasel Words only apply to polar warming caused by large amounts of CO2, the greenhouse effect. If CO2's greenhouse effect is strongest at the poles and if large amounts of CO2 causes warming, then I would expect ice cores wouldn't be able to show previous high levels of CO2 because of melting. Can you prove your claim that this isn't the case?

[CraigD]

Can you support the claim that there's never been significant melting at Vostok?

I have not claimed that there’s never been significant melting at the site in Antarctica where the Vostok Station is presently located. (we know with certainly that there’s never been melting of the grounds outside of the research station itself, because there’ve been recording instruments, and most of the time, people, there for the nearly 52 years since it was established – though it got rather balmy at the record-breaking -12.2 °C in Jan 2002 ;))

 

I explained that the interior of Antarctica has not had surface melting within the time period measured by ice cores from it, about the last 500,000 years. Much before this, until about 40,000,000 years ago, Antarctica had a tropical to subtropical climate. After it separated from South America around 23,000,000 years ago, Antarctica became increasingly isolated from heat sources, resulting in its present climate.

 

Support for the claim that Antarctica has the climate history I summarize above, and that its interior has been below freezing for many times longer than 500,000 years – at least 3,000,000 years – can be found in practically any encyclopedia or geology textbook, such as in the wikipedia article “Antarctica”.

 

Many of these sources, including the linked wikipedia article, suggest that the Antarctic climate has been practically as cold as at present since about 6,000,000 years ago, when geological evidence shows that its ice sheets reached about their present extent and thickness. Though I’m not a climatologist, my acquaintance with popular science literature and TV programs lead me to suspect that the Antarctic interior might – I hazard a very inexpert guess, here, which may be very wrong – have had summers warm enough for large melts until about 3,000,000 years ago, the time of the profound geological event of the formation of the Isthmus of Panama, which altered ocean currents into essentially their modern form, and climate into essentially its modern cycles, the current ice age.

 

An important point that I’ve been trying to impress upon you, Brian, and upon readers inexperienced in geology, is the importance of not confusing “very olds/long agos” of greatly different magnitudes. The Vostok ice core is very old – 400,000 years. The present Antarctic glaciation began very long ago – 6,000,000 years. The earth was very warm, and ice free even to high lattitudes, very long ago – more than 20,000,000 years. Not confusing these many “very olds/long agos” is essential to understanding paleoclimatology, and not falling prey to misperception common in discussions of present day climate change and its causes.

My "Ice Thermometer Bias" Weasel Words only apply to polar warming caused by large amounts of CO2, the greenhouse effect.

The informal term weasel words means phrases that appear to refer to be specific and meaningful, but are actually vague and ambiguous. The word “bias” is once flagged by website managing tools such as those used at wikipedia for checking to assure its not used as a weasel word.

 

You introduced the phrase “ice thermometer bias” in the following post

I think there may be a bias in ice core atmosphere samples, if high [ce]CO2[/ce] levels cause warming, and since we know that ice won't form above [math]32\degree F[/math], then it's impossible to use ice cores for CO2 measurements when the climate was very warm. This is known as the "Ice Thermometer Bias."

Referring to a phrase only you have used as one that some phenomena “is know as” is an example of a fallacious appeal to authority. While this can be effective rhetorical technique, it’s discouraged at hypography.

If CO2's greenhouse effect is strongest at the poles and if large amounts of CO2 causes warming, ...

I don’t think its accurate to say “CO2's greenhouse effect is strongest at the poles”.

 

Stated generally, the greenhouse effect is the phenomenon of a surrounding medium – in this discussion’s case, the Earth’s atmosphere – being more transparent to incoming radiation – in this case, sunlight, which has most of its energy in the visible spectrum – than it is to outgoing – in this case, the infrared. Therefore, it’s strongest where the most incoming radiation to which the atmosphere is transparent is present, and most absorbed and reemitted as infrared radiation to which the atmosphere is less transparent. High latitudes (the poles being the highest) receive less sunlight, and being snowy white, reflect more of it as visible light. By this reasoning, then, it’s accurate to say the greenhouse effect is weakest at the poles.

 

[ce]CO2[/ce] and other greenhouse gases are transparent to visible light but reflective of infrared, so contribute more strongly to the Earth’s greenhouse effect than other atmospheric gasses, even though their less common than others. However, for a greenhouse effect to occur, there must be many components to a system: incoming EM radiation (sunlight); a surrounding medium differently transparent to different EM radiation (the atmosphere); and a medium that absorbs EM radiation and remits a significant amount of it at longer wavelengths (the surface). So it’s inaccurate, I think, to say [ce]CO2[/ce] possesses the greenhouse effect.

 

[ce]CO2[/ce] is not the most significant greenhouse gas. [ce]H2O[/ce] (water) is. The focus on [ce]CO2[/ce]’s role in global warming is due to the relative ease with which the amount of it in the atmosphere can be controlled, and the relatively minor undesirable effects of reducing it, compared to reducing that of water.

... then I would expect ice cores wouldn't be able to show previous high levels of CO2 because of melting.

I fear from this statement that you’ve misunderstood the basic information about ice cores we’ve been discussing, Brian.

 

An ice cores is not incapable of showing melting of the snow from which they form. They are less valuable when melting has occurred, as the length of it into which melt water percolated has its contained gasses and particles mixed or lost. This is what’s meant by Readinger’s CSA Discovery guide and the wikipedia article “ice core” referring to above freezing temperatures as a “problem” rendering an ice core “severely degraded or completely useless”

 

For showing when periods of melting have occurred, there are better techniques than ice core analysis. For example, much of what we know of Antarctica’s early present ice age history is due analysis of the lakes and glacial moraines deep under its icesheet. In the case of presently ice-free areas, such as the Northeast US, everything we know about glacial movement and melting is due to analysis of such features, as the ice and meltwater is long gone.

[Michaelangelica]

Does the report mention Ice Cores?

 

Antarctic Ice Cores and Environmental Change

Climatic temperature against time from delta measurements taken on the ice core drilled at the Russian station, Vostok, in central Antarctica (Figure 2). Available data from this ice core so far extends back about 160,000 years.

However, drilling of the core still continues, and it is expected that, when drilling is completed in a few years time, an age of 500,000 years will have been reached.

 

Starting on the right-hand side of the graph at about 140,000 years ago, the climate was about 6°C colder than it is today.

This was an ice age period. Then at about 130,000 years ago, there was a quite rapid warming period until about 125,000 years ago, when the climate was, perhaps, 1°C or 2°C warmer than today.

These short warmer periods are called inter-glacials. We are in an inter-glacial now. From 120,000 to about 20,000 years ago, there was a long period of cooling temperatures, but with some ups and downs of a degree or two.

This was the Wisconsin Period, known as the last Great Ice Age.

From about 18,000 or 19,000 years ago to about 15,000 years ago, the climate went through another warming period to the next inter-glacial, - the one we are now in.

The most significant recent climate change findings are:

 

Surging greenhouse gas emissions:

Global carbon dioxide emissions from fossil fuels in 2008 were 40% higher than those in 1990.

Even if global emission rates are stabilized at present –day levels, just 20 more years of emissions would give a 25% probability that warming exceeds 2oC. Even with zero emissions after 2030. Every year of delayed action increase the chances of exceeding 2oC warming.

 

Recent global temperatures demonstrate human-based warming:

Over the past 25 years temperatures have increased at a rate of 0.190C per decade, in every good agreement with predictions based on greenhouse gas increases. Even over the past ten years, despite a decrease in solar forcing, the trend continues to be one of warming. Natural, short- term fluctuations are occurring as usual but there have been no significant changes in the underlying warming trend.

 

Acceleration of melting of ice-sheets, glaciers and ice-caps:

A wide array of satellite and ice measurements now demonstrate beyond doubt that both the Greenland and Antarctic ice-sheets are losing mass at an increasing rate. Melting of glaciers and ice-caps in other parts of the world has also accelerated since 1990.

 

Rapid Arctic sea-ice decline:

Summer-time melting of Arctic sea-ice has accelerated far beyond the expectations of climate models. The area of summertime sea-ice during 2007-2009 was about 40% less than the average prediction from IPCC AR4 climate models.

 

Current sea-level rise underestimates:

Satellites show great global average sea-level rise (3.4 mm/yr over the past 15 years) to be 80% above past IPCC predictions.

This acceleration in sea-level rise is consistent with a doubling in contribution from melting of glaciers, ice caps and the Greenland and West-Antarctic ice-sheets.

 

Sea-level prediction revised:

By 2100, global sea-level is likely to rise at least twice as much as projected by Working Group 1 of the IPCC AR4, for unmitigated emissions it may well exceed 1 meter. The upper limit has been estimated as – 2 meters sea-level rise by 2100. Sea-level will continue to rise for centuries after global temperature have been stabilized and several meters of sea level rise must be expected over the next few centuries.

 

Delay in action risks irreversible damage:

Several vulnerable elements in the climate system (e.g. continental ice-sheets. Amazon rainforest, West African monsoon and others) could be pushed towards abrupt or irreversible change if warming continues in a business-as-usual way throughout this century. The risk of transgressing critical thresholds (“tipping points”) increase strongly with ongoing climate change. Thus waiting for higher levels of scientific certainty could mean that some tipping points will be crossed before they are recognized.

 

The turning point must come soon:

If global warming is to be limited to a maximum of 2oC above pre-industrial values, global emissions need to peak between 2015 and 2020 and then decline rapidly.

To stabilize climate, a decarbonized global society – with near-zero emissions of CO2 and other long-lived greenhouse gases – need to be reached well within this century. More specifically, the average annual per-capita emissions will have to shrink to well under 1 metric ton CO2 by 2050.

This is 80-90% below the per-capita emissions in developed nations in 2000.

The Copenhagen Diagnosis

 

The methodology of ice core sampling is discussed here

Climate and Cryosphere (CliC)

[lemit]

Nice graph! Funny, the curve of that upswing at the end reminds me of some sports-related thing. I can't think what it is, though.

 

--lemit

[BrianG]

 

.... More specifically, the average annual per-capita emissions will have to shrink to well under 1 metric ton CO2 by 2050.

This is 80-90% below the per-capita emissions in developed nations in 2000.

 

The Copenhagen Diagnosis

 

The methodology of ice core sampling is discussed here

Climate and Cryosphere (CliC)

 

The methodology of ice core sampling doesn't mention error margins, why is that? Do you think reducing [ce]CO2[/ce] emissions 80-90% below 2000 levels will reduce our standard of living?

[Michaelangelica]

The methodology of ice core sampling doesn't mention error margins, why is that? Do you think reducing [ce]CO2[/ce] emissions 80-90% below 2000 levels will reduce our standard of living?

Why do you drag in ice core sampling when the article makes no mention of it?

[BrianG]

You wrote: "The methodology of ice core sampling is discussed here". I just find it odd to discuss a methodology without mentioning error margins.

[Michaelangelica]

You wrote: "The methodology of ice core sampling is discussed here". I just find it odd to discuss a methodology without mentioning error margins.

Brian you brought up the topic. Why?

[BrianG]

Did I? The original article in science news seems to have gone missing.

 

OK, I'll take credit for being the first to bring up possible problems with ice core methodology, if no one objects. I understand that these core measurements are one of the principle foundations of the theory that CO2 levels have always been low and followed warming, rather than causing warming, until man came along to burn fossil fuel. I am skeptical of this belief, just as I am skeptical of the belief we are living in an unprecedented warming trend. I bring up ice core methodology so I can learn more about the subject.

[freeztar]

Did I?

 

From what I can tell, ice cores preceded your mention of them.

 

The original article in science news seems to have gone missing.

?

OK, I'll take credit for being the first to bring up possible problems with ice core methodology, if no one objects. I understand that these core measurements are one of the principle foundations of the theory that CO2 levels have always been low and followed warming, rather than causing warming, until man came along to burn fossil fuel.

 

Where are you getting this info?

 

I am skeptical of this belief, just as I am skeptical of the belief we are living in an unprecedented warming trend. I bring up ice core methodology so I can learn more about the subject.

 

So why not start a thread dealing with said subject?

[BrianG]

...Where are you getting this info?

 

SpringerLink - Journal Article

 

 

So why not start a thread dealing with said subject?

 

I'd prefer to avoid infractions: http://hypography.com/forums/environmental-studies/7463-global-warming-a-fake-post286682.html#post286682

[Essay]

SpringerLink - Journal Article

 

Brian, could you post a couple of sentences (cut'n'paste) from the abstract so we can tell where this is headed? Thanks....

 

~

[BrianG]

Brian, could you post a couple of sentences (cut'n'paste) from the abstract so we can tell where this is headed? Thanks....

 

~ :singer:

 

I'ts a PDF image, rather than cut and paste, I'll tell you where I'm headed. I'm looking for explanations why 650,000 years of ice core formation have never shown even a single instance of [ce]CO2[/ce] levels as high or higher than contemporary levels.

[Essay]

I'ts a PDF image, rather than cut and paste, I'll tell you where I'm headed. I'm looking for explanations why 650,000 years of ice core formation have never shown even a single instance of [ce]CO2[/ce] levels as high or higher than contemporary levels.

Because 650,000 years isn't very long in geologic time; usually gas levels don't vary that much, that quickly.

 

p.s. That's off the top-of-my-head. I'm not even sure the premise is true, but I'm sure the answer is more complicated that what I said. I'd welcome any other suggestions, factors, links, etc.