Global warming

[Sustainability]

We know that global warming affects the weather and the earth's natural resources, but I need to know how it affects the health of people and animals around the world?

[A Childs Mind]

Hands Up it does. the heats will slowly begin to affect the way plants grow. wich will change our food. so yes it dose affect life on earth

[iNow]

http://www.epa.gov/climatechange/effects/eco.html

http://www.epa.gov/climatechange/effects/eco_animals.html

[rpf_81]

Humans will be affected the most due to global warming due to things like temperature increase. Many people believe that global warming began since the industrial revolution during the 18th century. During this time heat-trapping gases began to load in the atmosphere, gases such as carbon dioxide and methane. Global warming will have many negative consequences to humans, animals, and even plants.

[PoWn3d_0704]

Crap. All of it. Ever heard of the Earth's natural climate change? I do believe we just came out of an ice age... We will heat up, then cool down, then heat up again. It's just how it goes. We hardly contribute to the 'global warming' pollution. is it like... 5%? or less? anyways... present some really hard evidence (That's not from the EPA) and we'll see. Are we as humans helping the situation? No. Do i believe the Earth is indeed warming up? Yes. Are we in control of it? No. Are we the sole cause of it? No. It's just a normal thing the Earth has done and always will do. (until the sun goes super nova or something)

[iNow]

If the primary driver is natural processes, and not humans as you suggest, then what precisely is happening to cause the temperature to shift so quickly? Is it volcanic activity? Is it an increase in energy from the sun? Is it the melting of permafrost, or the decay of plants and animals? What is it, precisely, that is causing the climate to change, and to change at such an incredible rate?

 

You cannot just say "it's natural" without explaining what natural event is making it happen. Conversely, if you DO just say "it's natural" without explaining what natural event is making it happen, then you can safely be ignored and your comments dismissed.

 

Anthropogenic causes (human as primary driver) are the most well supported and evidenced factor available to us, and will remain so until you present an alternative to support your own little pet conjecture. Humans are the primary driver. Not the only one, but the primary, and simply saying "it's natural" isn't good enough to overturn the mountains of evidence which support the contention that we humans are the hugest contributor to the current warming, a warming which has trended upwards since the point when we reached the industrial revolution and began burning coal in large quantities.

 

 

 

 

 

Edited June 7, 2009 by iNow

[bascule]

Crap. All of it.

 

Even this?

 

http://en.wikipedia.org/wiki/IPCC_Fourth_Assessment_Report

 

Ever heard of the Earth's natural climate change? I do believe we just came out of an ice age... We will heat up, then cool down, then heat up again. It's just how it goes. We hardly contribute to the 'global warming' pollution. is it like... 5%? or less?

 

Yes, there are natural climate forcings at play too, but...

 

 

...there are also anthropogenic greenhouse gases which are dramatically outpacing the natural forcings driving climate change.

 

anyways... present some really hard evidence (That's not from the EPA) and we'll see.

 

The evidence is extensively documented in IPCC AR4 WGI: The Physical Science Basis. This is an extremely large report, but fortunately, they've boiled it down to a single sentence summary:

 

Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.

 

where "very likely" is footnoted as:

 

the assessed likelihood, using expert judgment [..'] is over 90%

 

I've noticed your post provides nothing in the way of things like evidence or well-reasoned argumentation in the form of peer-reviewed scientific literature. You might want to work on that.

[JohnB]

and to change at such an incredible rate?

Exactly what is "incredible" about it? The climate has changed naturally far faster in the past than in the last 100 years. I would also add that the warming from circa 1910 to 1940 is easily comparable to the 1970 -2000 period, as your own graph shows.

 

Even staunch AGW proponents accept that the warming of the early 1900s was natural. (Although I did see a rather well argued point somewhere that the CO2 increase may have been responsible. If I can find it again, I'll post a link.)

You cannot just say "it's natural" without explaining what natural event is making it happen.

Why not? The AGW side have no problem with doing it. Isn't that the standard reason for the current hiatus? That natural forcings are "masking" the CO2 warming signal? Nobody has yet put forward a hint of what these forcings actually are, but they must exist because the CO2 signal is being "masked".

 

As for the "Attribution Graph" that is so loved here, it's been shot to pieces before. The discussion ran for a couple of pages in this thread.

 

I again quote the IPCC;

The most recent study (Stern, 2005) suggests a decrease in global anthropogenic emissions from approximately 73 to 54 TgS yr–1 over the period 1980 to 2000

Suphate pollutants have been dropping yet the graph has an increasing negative forcing from them. The graph cannot be reconciled with the observed facts.

 

Why is it still being trotted out when it's veracity is so poor?

[iNow]

So, if it's natural, what is causing it?

You may as well be saying that too many pink unicorns are farting which causes it to warm at this point. You need evidence to support the cause you propose.

You propose it's natural. I say fine. What natural event is it to which you refer?

 

The human cause is incredibly well supported.

My point is truly that simple, regardless of how you feel about the images I shared.

[Mokele]

ven staunch AGW proponents accept that the warming of the early 1900s was natural. (Although I did see a rather well argued point somewhere that the CO2 increase may have been responsible. If I can find it again, I'll post a link.)

 

Reference, please.

 

Why not?

 

Because that's how science works.

 

Isn't that the standard reason for the current hiatus? That natural forcings are "masking" the CO2 warming signal? Nobody has yet put forward a hint of what these forcings actually are, but they must exist because the CO2 signal is being "masked".

 

References, again.

 

I've never seen the supposed "oddity" of recent years explain as anything but a stastical anomaly, the sort of random "blip" you get in any complex system.

 

Suphate pollutants have been dropping yet the graph has an increasing negative forcing from them. The graph cannot be reconciled with the observed facts.

 

Yes it can. Easily. Go on, read the graph. Really read it. Now read your reference.

 

Notice anything?

 

The graph ends in 1990, and sulfate forcing levels off before that, around about the early 1980's. The study you quoted references the period from 1980-2000 only.

 

These two are not contradictory.

[Reaper]

So, if it's natural, what is causing it?

 

Everybody knows that it's pirates that cause global warming (Duh!):

 

[bascule]

Suphate pollutants have been dropping

 

This is correct

 

yet the graph has an increasing negative forcing from them.

 

Correction: the graph showed a decreasing negative forcing response beginning around 1980, which does correlate to the time when emission of sulfate pollutants began to decrease globally. At the very end (towards the late '80s/early '90s) it does show an increasing negative forcing response. I cannot explain that.

 

The graph cannot be reconciled with the observed facts.

 

In order to make that claim (observed "facts" plural) you would need to point out an additional fact the graph cannot be reconciled with.

 

Just because the little purple line turns down at 1990 doesn't cause the whole house of cards to come crashing down. This is the case with climate modeling in general: while there are some inaccuracies, they are more than made up for by successes in other areas.

 

If I could find an updated graph based on a more recent simulation I would, however I cannot. I suspect they don't get made very often for just this reason: plotting the modeled forcing responses over time will be error-prone.

 

I believe that's why charts like the one iNow linked earlier showing the overall trends are what are commonly disseminated:

 

 

But, let's not throw the baby out with the bathwater here...

 

Why is it still being trotted out when it's veracity is so poor?

 

Because the argument it's being "trotted out" against is substantially poorer:

 

Crap. All of it. Ever heard of the Earth's natural climate change? I do believe we just came out of an ice age... We will heat up, then cool down, then heat up again. It's just how it goes. We hardly contribute to the 'global warming' pollution.

 

That chart, despite its inaccuracies, is easy for laymen to read as compared to the one shown earlier in this post as part of IPCC AR4.

[JohnB]

So' date=' if it's natural, what is causing it?

You may as well be saying that too many pink unicorns are farting which causes it to warm at this point. You need evidence to support the cause you propose.

You propose it's natural. I say fine. What natural event is it to which you refer?[/quote']

Perhaps you missed my point as you didn't answer my question. To wit;

"What exactly is "incredible" about the temp change in the second half of the 20th century?"

 

Mokele, I've not seen the warming in the first part of the 20th C attributed to CO2. If you have seen otherwise could you point me in that direction please?

I've never seen the supposed "oddity" of recent years explain as anything but a stastical anomaly, the sort of random "blip" you get in any complex system.

You speak of a "blip" as if it's a short term thing. The trend has been negative for more than 8 years now. How long does it have to continue before it stops being a "blip"?

 

AGW is supposed to be about the science, the more CO2 the higher the temp. I can dig that but the problem is that CO2 has been rising and the temp hasn't. Where has all the energy gone?

 

We are talking god knows how many joules here, where are they?

 

Bascule, we both tried to find some supporting evidence in the published literature for that graph and came up blank. Remember this exchange?

Could you please show where in that paper the forcings are defined quantitativly? Quick answer' date=' they are not. The reference to forcings leads here. I quote from the abstract:

In addition to the five individual forcing experiments, an additional eight sets are performed with the forcings in various combinations. The late-twentieth-century warming can only be reproduced in the model with anthropogenic forcing (mainly GHGs), while the early twentieth-century warming is mainly caused by natural forcing in the model (mainly solar).

There is no mention here of using actual measured values. (Something that I have asked for before.) Loose translation of the first sentence above: "We did 1 run using our estimate of each individual forcing, then 8 runs where we varied our estimates." [/i']Wanna bet they compared each run to the climate record before varying the estimates? I'm willing to be wrong here as the actual paper is behind a paywall, so if someone can provide the methodology used in the paper (with quotes) I'll concede the point.

No, the values aren't measured because there's no way to quantitatively measure them, especially on a global scale.

Just because the graph's a pretty picture that gets your message across doesn't make it right, for that is true of all propaganda, isn't it?

 

In general.

 

I've yet to see anybody here saying that CO2 is not a greenhouse gas, it is. I think the differences of opinion concern how sensitive the climate is to CO2 and more specifically, how the feedbacks behave. Have we underestimated some forcings and therefore have attributed too much power to CO2?

 

A simple example: Is cloud cover percentage a positive feedback or a negative forcing? Or both?

 

Is CO2 the "big bad" it's marketed as?

 

Do we need to reconsider land use and UHI in light of Jones et al 2008?

 

IPCC TAR relied on the Letter to Nature by Dr. Jones to conclude that UHI effect is minimal;

These results confirm the conclusions of Jones et al. (1990) and Easterling et al. (1997) that urban effects on 20th century globally and hemispherically averaged land air temperature time-series do not exceed about 0.05°C over the period 1900 to 1990

 

AR4 puts it at;

effects of urbanisation and land use change on the land-based temperature record are negligible (0.006ºC per decade) as far as hemispheric- and continental-scale averages are concerned

(IPCCAR4WG1 Chapter 3 Page 237)

 

However in Jones 2008 we find;

Urban-related warming over China is shown to be about 0.1°C decade−1 over the period 1951–2004,

 

Previous assessments were based on .006 degrees/decade but new research by the same person now puts it at .1 degrees/decade. Have we underestimated the UHI effect?

[iNow]

What is this natural cause? The human cause is incredibly well supported, and will only be displaced by CLEAR data to the contrary.

 

I accept your contention that there are sources of error in the measurements, however, I reject as non-sequitur your conclusion that these errors are enough to overturn anthropogenic origin.

[Mokele]

Mokele, I've not seen the warming in the first part of the 20th C attributed to CO2. If you have seen otherwise could you point me in that direction please?

 

I haven't either, but I couldn't turn up much on my searching on the topic in either direction.

 

You speak of a "blip" as if it's a short term thing. The trend has been negative for more than 8 years now. How long does it have to continue before it stops being a "blip"?

 

Show me this mythical "decrease". Every graph I've found shows at most a leveling off, with some minor wobbling.

 

As for when it becomes more than a blip, that's determined statistically. It depends on the magnitude of the change, the duration, the consistency, and the natural variability of the system.

 

AGW is supposed to be about the science, the more CO2 the higher the temp. I can dig that but the problem is that CO2 has been rising and the temp hasn't. Where has all the energy gone?

 

The ocean would be one candidate, and unfortunately, we can only measure the very top of it.

 

Bascule, we both tried to find some supporting evidence in the published literature for that graph and came up blank. Remember this exchange?

 

You're relying upon an abstract? And you haven't read the paper? Are you serious?

 

Previous assessments were based on .006 degrees/decade but new research by the same person now puts it at .1 degrees/decade. Have we underestimated the UHI effect?

 

Possibly, though we should note that there are likely to be differences between the UHI in developed vs developing countries.

 

I also note you failed to include the whole quote, which states: "Urban-related warming over China is shown to be about 0.1°C decade−1 over the period 1951–2004, with true climatic warming accounting for 0.81°C over this period."

[iNow]

Show me this mythical "decrease".

 

There are three factors at play here:

 

1) La Niña has resulted in cooling to some extent, while the El Niño phenomenon made 1998 especially hot.

2) He's arbitrarily choosing a hot year as the starting point for the time scale, one of the hottest years on record, which makes it look as if we've been cooling. Once you go out for 2 or 3 decades, the trends is rather obviously upward. The "it's been cooling claim" is representative of cherry-picked data and arbitrary graphing time scales, not of an actual trend in our global yearly average temperature.

3) It's been steady (and even slightly upward), not cooling.

 

See below for a visual and evidence based support of my points #2 & 3:

 

 

 

 

 

[swansont]

AGW is supposed to be about the science, the more CO2 the higher the temp. I can dig that but the problem is that CO2 has been rising and the temp hasn't. Where has all the energy gone?

 

OK, let's recast the question. Temperature has risen by somewhere between 0.5 and 1.0 ºC in the last ~ century, and almost 0.5 ºC in the last several decades, depending on the exact starting point you use. (The exact number is probably unimportant for this discussion). If anthropogenic CO2 has had a negligible effect, where did the energy come from to account for the temperature rise?

 

Since we know that CO2 is a greenhouse gas and we can model its effects, the prior question is the one that needs to be answered to gain any traction in the "it's natural variation" discussion, and I haven't seen a lot that isn't easily debunked. We know it's not the sun — that's been studied pretty extensively. So it has to be some other source where energy could be stored/released.

 

And the problem is that if you have a valid answer to this, it probably is a good candidate for the answer to "where did the energy go?"

[JohnB]

2) He's arbitrarily choosing a hot year as the starting point for the time scale, one of the hottest years on record, which makes it look as if we've been cooling.

Bullshit. 2009 - 8 years is 2001, not 1998. In every one of these discussions I've gone to great pains to avoid 1998 as a starting point for exactly the reason you say. If you're going to argue, then at least have the courtesy of actually arguing against the point made, not some strawman.

 

Lucia plotted the temps here. Since 2000, slightly positive, since 2001 slightly negative. Personally I doubt either result are statistically significant. Either way, we ain't making the predicted .18 degrees/decade, are we?

 

I would add that 2000 is a reasonable start point because that is where the model runs used in AR4 started.

1) La Niña has resulted in cooling to some extent, while the El Niño phenomenon made 1998 especially hot.

A point BTW that is conveniently left out in the IPCC TAR summary.

 

And you still haven't answered the question;

"What exactly is "incredible" about the temp change in the second half of the 20th century?"

 

Mokele.

 

As I understand the current "State of Play":-), the warming in the first half of the 20th C is put to natural causes. Around about 1940 particulate emmissions came into play causing a slight cooling trend. At some point in the 1940-1970 period CO2 forcing overtook the natural forcings and was eventually strong enough (combined with reductions in emmissions due to "Clean Air Acts") to bring about the second warming period. Say 1980-2000.

 

You might note that the quote from Meehl et al states;

while the early twentieth-century warming is mainly caused by natural forcing in the model (mainly solar).

 

As for when it becomes more than a blip, that's determined statistically. It depends on the magnitude of the change, the duration, the consistency, and the natural variability of the system.

Change from trends, or change from projections? We have already severly departed from the projections and the most current estimates I've seen are that warming will not recommence until circa 2015. How many years of statistically blah do we need to suspect the projections might be wrong?

You're relying upon an abstract? And you haven't read the paper? Are you serious?

The conversation went for a number of pages, I simplified. Bottom line, the graph is claimed to be based on 2 papers, I was able to find one of them and there is nothing in that paper that could generate the graph. The exchange starts on about page 4 of the linked thread.

Possibly, though we should note that there are likely to be differences between the UHI in developed vs developing countries.

I take your point, but I think in this context the line between "developed" and "developing" is rather blurred.

 

Just using Wiki.

US population 1900: 76,212,168

US population 2000: 281,421,906

 

In 1900 there was no air conditioning, no aircraft, virtually nobody owned a car and there was only 1/4 of the population. The city of Washington alone went from 3 million in 1960 to 6 million in 2000.

 

I put it to you that in terms of UHI, all western nations were "developing" during the 20th C. Consequently the UHI effect during the 20th C has been seriously underrated.

 

I didn't ignore the full quote, but since you mentioned it. What Jones found was that out of the .81 degree rise in the Chinese region more than .5 degree was caused by UHI. Hence warming by natural or CO2 forcings account for .31 degree or less than half the observed warming.

 

OK, let's recast the question. Temperature has risen by somewhere between 0.5 and 1.0 ºC in the last ~ century, and almost 0.5 ºC in the last several decades, depending on the exact starting point you use. (The exact number is probably unimportant for this discussion). If anthropogenic CO2 has had a negligible effect, where did the energy come from to account for the temperature rise?

The sun? If there was a natural reduction in cloud cover over the period, then it would get warmer over that period.

 

It all comes back to the models really since they are what show that CO2 must be the big bad. But if their sensitivities are wrong?

Spencer and Braswell 2008 in the Journal of Climate show that:

Nevertheless, since FG’s (Forster and Gregory 2006) observational estimates of total (SWLW) feedback already represent a lower climate sensitivity than that produced by any of the 20 coupled climate models analyzed by Forster and Taylor (2006), our results suggest the possibility of an even larger discrepancy between models and observations than is currently realized.

 

We know that CO2 increase is enough to account for the warming if the climate sensitivity to CO2 is as high as we think it is. However, if the sensitivity is lower than assumed, then CO2 is no longer enough to account for the warming.

 

You may be interested in this article by Dr. Spencer (the full paper is in review). Where he shows that:

there were NO five year periods from ANY of the IPCC model simulations which produced a feedback parameter with as low a climate sensitivity as that found in the satellite data.

 

So the models say high CO2 sensitivity and the satellite data says low sensitivity. Which do you believe?

 

Everybody please note. At no time have I said that CO2 has no effect. My point is that if it has negligable effect, then efforts at CO2 reduction will also have negligable effect and are therefore pointless. (Although that is not to say that we should not pollute less.)

[iNow]

Bullshit. 2009 - 8 years is 2001, not 1998. In every one of these discussions I've gone to great pains to avoid 1998 as a starting point for exactly the reason you say. If you're going to argue, then at least have the courtesy of actually arguing against the point made, not some strawman.

I was mistaken in my starting year, yes. Sorry about that. However, I must say, shortening the time scale even further (from 1998 instead to 2001) really doesn't help your case, and might, in fact, make your argument that much weaker.

 

Either way, you are getting worked up and making claims of cooling over this set of data (per your own reference):

 

 

 

I find that strange. First, eight years is not enough data to discuss overall climatological trends. This is why I put much greater confidence in the 30 year or greater averages. Second, when you average the trends from each of the studies listed, you still have a 0.01 degree C upward trend. So, you source doesn't support your contention.

 

 

"What exactly is "incredible" about the temp change in the second half of the 20th century?"

The FACT that it's caused by humans, and is hitting trigger points for additional warming. For example, the melting of the permafrost is causing carbon and methane to be increased at greater concentrations than previously thought possible.

 

 

http://www.newscientist.com/article/mg18725124.500

THE world's largest frozen peat bog is melting. An area stretching for a million square kilometres across the permafrost of western Siberia is turning into a mass of shallow lakes as the ground melts, according to Russian researchers just back from the region.

 

The sudden melting of a bog the size of France and Germany combined could unleash billions of tonnes of methane, a potent greenhouse gas, into the atmosphere.

 

<...>

 

Siberia's peat bogs formed around 11,000 years ago at the end of the last ice age. Since then they have been generating methane, most of which has been trapped within the permafrost, and sometimes deeper in ice-like structures known as clathrates. Larry Smith of the University of California, Los Angeles, estimates that the west Siberian bog alone contains some 70 billion tonnes of methane, a quarter of all the methane stored on the land surface worldwide.

 

His colleague Karen Frey says if the bogs dry out as they warm, the methane will oxidise and escape into the air as carbon dioxide. But if the bogs remain wet, as is the case in western Siberia today, then the methane will be released straight into the atmosphere. Methane is 20 times as potent a greenhouse gas as carbon dioxide.

 

In May this year, Katey Walter of the University of Alaska Fairbanks told a meeting in Washington of the Arctic Research Consortium of the US that she had found methane hotspots in eastern Siberia, where the gas was bubbling from thawing permafrost so fast it was preventing the surface from freezing, even in the midst of winter.

 

An international research partnership known as the Global Carbon Project earlier this year identified melting permafrost as a major source of feedbacks that could accelerate climate change by releasing greenhouse gases into the atmosphere. "Several hundred billion tonnes of carbon could be released," said the project's chief scientist, Pep Canadell of the CSIRO Division of Marine and Atmospheric Research in Canberra, Australia.

 

 

http://www.zmag.org/znet/viewArticle/5644

The area, which covers the entire sub-Arctic region of western Siberia, is the world's largest frozen peat bog and scientists fear that as it thaws, it will release billions of tonnes of methane, a greenhouse gas 20 times more potent than carbon dioxide, into the atmosphere.

 

It is a scenario climate scientists have feared since first identifying "tipping points" - delicate thresholds where a slight rise in the Earth's temperature can cause a dramatic change in the environment that itself triggers a far greater increase in global temperatures.

 

<...>

 

"This is a big deal because you can't put the permafrost back once it's gone. The causal effect is human activity and it will ramp up temperatures even more than our emissions are doing."

 

In its last major report in 2001, the intergovernmental panel on climate change predicted a rise in global temperatures of 1.4C-5.8C between 1990 and 2100, but the estimate only takes account of global warming driven by known greenhouse gas emissions.

 

"These positive feedbacks with landmasses weren't known about then. They had no idea how much they would add to global warming," said Dr Viner.

 

 

So yeah... I find it strange that... not only are you arguing that humans have a negligible impact on climate despite the enormous evidence to the contrary across practically every involved research domain, but also that you are somehow using an average of global climate change over the past 8 years to support your views... When that data doesn't average to suggest cooling.

 

Average the trends shown in your graph. 0.01 degree C upward over the past 8 years.

 

Now, yes... once those methane concentrations are released, they will totally eclipse human contributions. However, it is we humans who are the PRIMARY driver toward those thresholds, and that is something we have the power to change... which is why these discussions get so heated. We can do something about it, and it's a total and ignorant waste of time arguing about a questionable 8 year set of data when all of the rest amply demonstrates the cause.

 

It's like arguing evolution with a creationist sometimes, except a failure to accept this particular fact can lead to the demise of the human race, and many of the countless life forms on Earth.

 

 

 

As per the models... I do accept there are various faults and limitations, but I'm afraid most of those faults suggest that we've been far too conservative in our estimates. As a general rule, we didn't really account for the quickening from methane in permafrost, nor the cavitations and subglacial erosion making the ice sheets disappear more quickly.

 

Our models missed the mark... yes. They didn't show enough warming or enough ice sheet melt.

 

 

http://efdl.cims.nyu.edu/publications/refereed/jclimate_nonlinear_warm_08.pdf

We have determined that the response of ice shelf basal melting to ocean warming follows a quadratic relation. This occurs because the melt rate is primarily governed by the transfer of heat through the oceanic boundary layer beneath the ice shelf, which is influenced by changes in both oceanic temperature and velocity. As the ocean warms offshore of an ice shelf, both of these quantities increase linearly, leading to a quadratic increase overall. Examination of a range of model configurations shows that altering topography changes the magnitude of the melt rate.

 

<...>

 

The quadratic melt rate dependence should be of interest to scientists concerned about the long-term effects of global warming on Antarctic climate stability as a whole. First, it implies that for a given topography, ice shelves melted by warm waters are more sensitive to temperature changes. Second, if a steady warming of waters offshore of an ice shelf were to take place, then our results imply that melting of the ice shelf base would increase at an accelerating rate. Whether this leads to thinning or collapse of the ice shelf will also depend upon glaciological and meteorological processes, but the fact that the melting increase accelerates requires that some other process counteracts melting in an above-linear fashion to stabilize the ice shelf and, therefore, the ice sheet feeding it.

 

 

http://www.ggy.bris.ac.uk/personal/StephenPrice/images/images/documents/Price+_JGlac_54no184_2008.pdf

Recent observations of increased discharge through fast-flowing outlet glaciers and ice streams motivate questions concerning the inland migration of regions of fast flow, which could increase drawdown of the ice-sheet interior.

 

 

 

http://www.springerlink.com/content/t1265r6548477378/fulltext.pdf

Another complication is that ice sheets do not grow and decay simply and linearly with global average temperature. During Heinrich events, the Laurentide ice sheet surged into the ocean in response to no evident climate forcing at all. Once an ice sheet forms, its high albedo tends to stabilize it, perpetuating its own existence. However, this effect did not save the Eemian world from 4–5 m of sea level rise in a world only about 1°C warmer than preanthropogenic, nor is it evident at any other time in the past from Fig. 3. In spite of the potential complications, the figure shows a clear correlation between global temperature and sea level in the geologic past.

 

The forecast for the coming century is for only 0.2–0.5 m under business-as-usual (A1B scenario), in spite of a temperature change of 3°C (Solomon et al. 2007). The sea level response to global temperature is one hundred times smaller than the covariaton in the past. The contrast between the past and the forecast for the future is the implicit assumption in the forecast that it takes longer than a century to melt a major ice sheet.

 

There are reasons to believe that real ice sheets might be able to collapse more quickly than our models are able to account for, as they did during Meltwater Pulse 1A 19 kyr ago (Clark et al. 2004) or during the Heinrich events (Clark et al. 2004), neither of which are well simulated by models. Ice sheets are also demonstrating tricks today which models don’t predict in advance, such as accelerating flow (Zwally et al. 2002) and seismic rumbling (Ekstrom et al. 2006) following the seasonal cycle in Greenland. Ice shelves such as the Larsen B on the Antarctic peninsula collapse catastrophically, and the ice streams that flow into them accelerate (Bamber et al. 2007). Recognizing the insufficiency of current ice sheet models to simulate these phenomena, IPCC excluded what they call “dynamical changes in ice sheet flow” from their sea level rise forecast.

 

 

 

So, no... I'm not exactly "warmed" by a chart that shows an average upward increase of 0.01 degree C over the last 8 years.

Edited June 9, 2009 by iNow
left out a zero

[Mokele]

Bullshit. 2009 - 8 years is 2001, not 1998. In every one of these discussions I've gone to great pains to avoid 1998 as a starting point for exactly the reason you say. If you're going to argue, then at least have the courtesy of actually arguing against the point made, not some strawman.

 

So....you're getting data from the future? Because last time I checked, 2009 isn't finished yet.

 

Either way, we ain't making the predicted .18 degrees/decade, are we?

 

Wait, so a giant, planet-wide system with huge historical dependency and complex, non-linear, interacting factors, don't behave in a linear fashion?

[swansont]

The sun? If there was a natural reduction in cloud cover over the period, then it would get warmer over that period.

 

This is something that could be tested and modeled. Has anyone done it?

[CaptainPanic]

I would add that 2000 is a reasonable start point because that is where the model runs used in AR4 started.

When talking about climate, a reasonable point is, by convention, 30 years ago.

conveniently, this 30 year period encompasses more than 2 solar cycles, so that any fluctuations from the 11-year solar cycle are included.

It also averages out severe weather.

 

Taking 1998, or 2001, or 2000 as starting point is wrong, from a statistics point of view. Any discussion about climate should be just that: statistics.

[JohnB]

Firstly apologies for slow replies. I'm currently shaped to 64k and so d/loading a pdf link to read takes a long time. As does finding research to back my case.

 

iNow, I just love science by press release, don't you? Especially 4 year old press release. (I find it interesting that there seems to be a dearth of recent articles listed on Google scholar when searching for the terms permafrost and methane. Although there are quite a number concerning microbes.)

 

A sinple question. If the permafrost was laid down 11,000 BP and it was warmer 8,000 BP than it is now, why don't we see this massive increase in methane in the record? If it's going to melt now because of the temp, then it would have melted then, wouldn't it?

 

You may be interesed in this though. While less alarming than you news articles, it is at least peer reviewed. I quote;

The heat transfer and gas diffusion model shows that in the future permafrost is likely to contribute less than 10 Tg yr-1 or 2% of the currently yearly source of methane under current climate change scenarios

 

My point with the graph was that bugger all is happening. Slightly positive, slightly negative, take your pick. The bottom line is that statistically, nothing is happening.

 

Like you I do look at the 30 year trend, but unlike you I also consider the shorter periods. The reason for this is simple. Using only the 30 year trends, you will always lag behind what is actually happening.

 

Let's assume that temp increase and decrease were monotonic at a rate of .1 degree/decade and that they followed a 40 year cycle. (I'm not saying they do, this is just to illustrate the point.) So a 40 year increase is followed by a 40 year decrease. Up then down.

 

In year 40, the 30 year trend will show a rise of .1 degree/decade, which is correct. However, by relying only on the 30 year trend you will be 15 years into the cooling phase before the trend line levels out. You will be 30 years into the cooling phase before your 30 year trend line shows the true trend of -.1degree/decade. The reverse is true when you move from a cooling to a warming phase.

 

See the problem? While it is wrong to only consider short periods, it can be equally misleading to only consider long periods.

 

I can't watch the Nova program ATM for the reason given above, however I must ask whether it is more accurate than the blurb accompanying it.

Over 100 million people live within three feet of sea level—the very amount that experts expect seas to rise by 2100.

Really? IPCC AR4 Chapter 10 Table 10.7 puts the maximum rise under their A1F1 scenario at .59 metres. Less than 2/3 of what the program is saying "experts expect".

 

despite the enormous evidence to the contrary across practically every involved research domain,

So far, you've provided two news articles and a TV program.

 

The three papers you linked to.

 

Let me fill in the gap you left in the first;

It is important to note that we make no claims about the source of the hypothesized warming. Several studies have proposed that oceanic warming has triggered increased mass loss from the grounded Antarctic ice sheet (e.g., Shepherd et al. 2004), but no persistent warming (of waters actually melting an ice shelf) has yet been measured. Warm waters that penetrate ice shelf cavities upwell from great depths and might not be directly impacted by atmospheric warming on short time scales.

(Emphasis mine.)

Also;

Several authors and the 2007 Intergovernmental Panel on Climate Change report (Lemke et al. 2007) suggest that a single melt rate–temperature sensitivity (in m yr1 °C1) is applicable to all ice shelves and temperatures, but our results imply that this is inaccurate in general.

Shock, horror. They must be wrong, they disagree with the IPCC. Actually I thought this a very interesting paper, I must look for more by these gents.

 

Your second link;

Recent observations of increased discharge through fast-flowing outlet glaciers and ice streams motivate questions concerning the inland migration of regions of fast flow, which could increase drawdown of the ice-sheet interior.

What's wrong with "motivating questions? This is a good thing. Their actual conclusions are also worth reading.

Upstream migration of the sliding transition increases with the size of the perturbation and with the degree of non-linearity assumed in the relation linking basal stress to basal motion. Here, a 15% reduction in the stiffness of the basal layer causes the sliding transition to migrate upstream by about 35 x the ice thickness in 250 years.

 

I'd heard of papers like your third, but hadn't read one. Interesting. The biggest problem I see is in the extrapolation of sea level rise. Comparisons to Heinrich events is just plain dumb. (Unless you have a Laurentide Ice Sheet hiding somewhere?) There just aren't any multi kilometre thick ice sheets to provide the needed water.

 

Don't you find it a bit odd that there is so much mention of only positive feedbacks? Negatives must exist and must be very powerful. If not, then Earth would have become a lifeless hot ball eons ago.

 

It didn't happen when temps were much higher than today and it didn't happen when CO2 was far higher than today.

Wait, so a giant, planet-wide system with huge historical dependency and complex, non-linear, interacting factors, don't behave in a linear fashion?

I never said it should. However if you look at table 10.5 of AR4, none of the projections look remotely like reality. Again, how many more years of statistical nothing is needed?

 

Also, do you agree that for UHI purposes all nations were "developing" during the 20th C?

 

This is something that could be tested and modeled. Has anyone done it?

As I said, the Spencer paper is in review. Although it is available at his blog by following the link.

[JohnB]

(I decided to delete my rant to the sceptics, and replaced it with the following position to JohnB).

And that position is?

 

I'm a bit confused by this report from Worldchanging.

 

What's to be confused about? You can hardly argue with a group of self declared;

global network of independent journalists, designers and thinkers covering the world's most intelligent solutions to today's problems.

 

I must shield my eyes from their brilliance lest I be blinded.

[bascule]

JonB, I'm not sure what point you're trying to make with those particular quotes/papers other than we are not seeing similar trends in Antarctic sea ice/ice sheets that we are in Arctic sea ice/ice sheets.

 

The warming trends are asymmetrical between the northern and southern hemispheres.