'Naysayers Guide to Global Warming.

[DAVID SNOW]

I think that's a bold claim. The recent cyclical ige ages seem to have only started since Antarctica developed an permanent ice sheet - the exact date this happened isn't clear but it's within the last 50 million years.

Well, it's possible I suppose, but, over the times scales of AGW (hundreds, maybe thousands of years) that concern us it's imo unlikely to be relevant.

Pennsylvanian ice age... 320 million years ago, Permian ice age... 300 million years ago

[Devonian]

Pennsylvanian ice age... 320 million years ago, Permian ice age... 300 million years ago

Yes, I don't disagree, maybe permanent land ice at other times as well. Was there another before the recent ones? We're they regular up until recently (last 50 M years)? I don't think so.

[Essan]

Just a thought: if global warming is linked to sunspot activity, why's it getting even warming during a solar minimum? Last I looked there ain't being many sunpots during one of the warmest (globally) winter's on record .....

And besides, wouldn't solar activity affect both hemispheres almost equally? How does it explain the distribution of observed change?

Yes, I don't disagree, maybe permanent land ice at other times as well. Was there another before the recent ones? We're they regular up until recently (last 50 M years)? I don't think so.

The current Ice Age has effectively been in force for about 3 million years - during which time there has been periodical advance and retreat of N Hemisphere ice sheets. At least a partial ice sheet is believed to have existed in Antarctica fro about 35 million years.

Before then there was 100 million years or more with no major polar ice sheets.

Continental configuration seems to be one of the main reasons for a Glacial Epoch starting - although other non terrestrial factors cannot be ruled out. The reason for the short term advance and retreat of ice sheets is yet to be adequately explained, although Milankovitch cycles almost certainly play an important role. Volcanic activity does not appear to have any important role: whilst the Mount Toba eruption c74kya precipitated one of the coldest periods of the last ice age, a warm interstadial set in within a few hundred years; it appears to have had little impact on the overall cycle of stadial and interstadial.

[Devonian]

Just a thought: if global warming is linked to sunspot activity, why's it getting even warming during a solar minimum? Last I looked there ain't being many sunpots during one of the warmest (globally) winter's on record .....

And besides, wouldn't solar activity affect both hemispheres almost equally? How does it explain the distribution of observed change?

The current Ice Age has effectively been in force for about 3 million years - during which time there has been periodical advance and retreat of N Hemisphere ice sheets. At least a partial ice sheet is believed to have existed in Antarctica fro about 35 million years.

Before then there was 100 million years or more with no major polar ice sheets.

Continental configuration seems to be one of the main reasons for a Glacial Epoch starting - although other non terrestrial factors cannot be ruled out. The reason for the short term advance and retreat of ice sheets is yet to be adequately explained, although Milankovitch cycles almost certainly play an important role. Volcanic activity does not appear to have any important role: whilst the Mount Toba eruption c74kya precipitated one of the coldest periods of the last ice age, a warm interstadial set in within a few hundred years; it appears to have had little impact on the overall cycle of stadial and interstadial.

Agreed. I'd say that sums it all up pretty darn well .

[Mondy]

Just a thought: if global warming is linked to sunspot activity, why's it getting even warming during a solar minimum? Last I looked there ain't being many sunpots during one of the warmest (globally) winter's on record .....

Shamelessly pinched from here may explain more detail for you. It's not just to do with sunspot/solar minimum:

Let me just give a little bit more information about the issue.

It is pure coincidence that the average global temperature has increased as we began the industrial age. Just because two things happen at the same time does not mean there is a causal relation between them.

I go to work every morning an so does my next door neighboor. On the weekends I stay home and my neighboor also stays home. It does nto mean that my neighboor is staying home because of me. One thing does nto cause the other - they are merely coincident.

If you are not convinced, then how would you explain that the greater portion of the global temperature rise happened before 1940 ? 70 years ago there were very few cars, no commercial air travel at all, and our level of industrialization was just a fraction of what we have today.

One more thing to think about:

Our Sun is not a constant and 'rock steady" source of light and energy. our Sun has a pulse. In fact it has many pulses. One of them you have already probably heard about - the 11 year sun spot cycle. Every 11 years the sunspot activity increases dramatically.

There is another much slower "pulse" which has a periodicity of abotu 1,500 years. Every 15 centuries or so, the Sun's energy output increases by up to 3 or 4% of it's "normal" value. This has teh effect of changing the Earth's average temperature by 1 or 2 degrees centigrade. We are in one of those "high solar output" phases. Whatever humans can do whlie toyling around on the surface of the Earth like microscopic little ants CANNOT compare to such a large change in solar energy flux.

We are puny and powerless to fight against the Sun.

As i say, pinched from elsewhere, so can't claim any of it

Edited February 28, 2007 by Mondy

[Devonian]

Shamelessly pinched from here may explain more detail for you. It's not just to do with sunspot/solar minimum:

As i say, pinched from elsewhere, so can't claim any of it

A temperature 'pulse' of some 1-2C would be plain as a pikestaff in any paleoclimate data. It's simply not there. Indeed, I'd go farther, I'd bet you can't find any evidence whatsoever for a prolonged 1500 year cycle with global temperature changes of 1-2C and solar output increasing by 3-4%. Not here, not in the IPCC, not on any sceptic site, not anywhere. Over to you

Edit: refinded to reflect the claim in the post above.

Edited February 28, 2007 by Devonian

[Mondy]

. Over to you

You'll have to wait! I'm heading off for a good bit

You could, of course, join that particular forum and tell said poster he/she is wrong, but i think you'll probably prefer to stay around here for a while..

What i would like to mention is how very, very interesting this thread has now become after a sluggish start (!)..cuedos to you all!

[Hiya]

A temperature 'pulse' of some 1-2C would be plain as a pikestaff in any paleoclimate data. It's simply not there. Indeed, I'd go farther, I'd bet you can't find any evidence whatsoever for a 1500 year cycle with temperature changes of 1-2C. Not here, not in the IPCC, not on any sceptic site, not anywhere. Over to you

I think the temprature part is hard to prove, what about the cycle? You trying to say that doesn't exist?

[Devonian]

I think the temprature part is hard to prove, what about the cycle? You trying to say that doesn't exist?

No, there is, I think, evidence of a 1,500 yr cycle in some places. I'm responding to the claims, and I've edited my post to reflect that . Like I say 1-2C globally and 3-4% change in solar output every 1, 500 yrs would be pikestaff plain in the paleo record - imo.

Edited February 28, 2007 by Devonian

[Hiya]

No, there is, I think, evidence of a 1,500 yr cycle in some places. I'm responding to the claims, and I've edited my post to reflect that . Like I say 1-2C globally and 3-4% change in solar output every 1, 500 yrs would be pikestaff plain in the paleo record - imo.

Can you prove your point that the cycle does not precipitate a 1-2C global rise in tempratures?

[blitzen]

Pinched or not Mondy, it makes sense to me! I have never been able to understand why, the fact that it has all happened before, that some people appear to disregard such evidence which is there for all to see in the ice core samples and, more recently, the coral samples. I sometimes think that all the technology available to us nowadays amounts to no more than a stick with which to break our own backs! and keep highly paid 'Ologists' in highly paid jobs! using very expensive equipment which was unavailable during the last climate change. How therefore, do we know exactly what, where, how and when this developed with any degree of certainty? I do honestly think that the whole climate issue is a repetitive natural occurrence and will probably be shot down in flames for it

Blitzen.

Edited February 28, 2007 by Blitzen

[Devonian]

Can you prove your point that the cycle does not precipitate a 1-2C global rise in tempratures?

Please read what I wrote. I said "I'd bet you can't find any evidence whatsoever for a prolonged 1500 year cycle with global temperature changes of 1-2C and solar output increasing by 3-4%.". OK? . Now you ask me to disprove something I'm asking for evidence of

[Essan]

Why is solar activity not warming the Antarctic? This is often presented as a problem with the carbon emissions theory, but surely holds even more true for non anthropogenic causes.

I can't see how changes in solar activity (indeed, any external forcing) can explain observations?

btw Mondy - have you read Fred Singer's book Unstoppable Global Warming: Every 1500 Year ? I have it on order from Amazon.

[parmenides3]

Rather than give an opinion based on a personal prejudice (either way), I've had another look at the AR4 and come up with some stuff in support of the argument that AGW is exaggerated. See what you think.

Wherever possible, I've kept the numbers within the known bounds of probability and the IPCC's own error bars.

First; it is really hard to argue against the case that CO2 warms the atmosphere, but by how much? The lower estimate of the IPCC is <+1.50 W/M2.

It is also hard to argue that there hasn't been recent warming, so it has to be coming from somewhere.

Top estimates of solar variation put it at 0.3W/m2, though some reputable people have suggested that this is a conservative estimate: for the sake of argument, let's say that Stott et. al. (a 'legit.' paper, unlike Solanki or some others) are correct. The actual figure 'should' be ~0.5W/M2.

What other factors come into play? There has been no recent change in volcanicity, or a major eruption/slowdown in annual outgassing, so the forcing (either way) from volcanoes is still around 0.

What about the Milankovitch cycles?: on the timescales we are dealing with here, no marked change outside normal variations is likely to be measurable, so they don't account for the changes, in the short term.

Aerosols; an area of 'low' understanding and large error bars. Let's say that the net direct and indirect (cloud albedo) aerosol effect is at the lower end (not so negative) of the estimates: net forcing here would be as low as ~-0.5W/M2.

Positive forcing from Ozone and water vapour are also limited: total of around +0.2w/M2

There are a few other to play with too. What comes out? Even if the forcing from CO2 is 1.5W/M2, the net anthropogenic forcing (positive effects minus negative effects) could be as low as 0.6W/M2 - this is the bottom end of the IPCC estimate. Messing around with the variables allows us to permit the possibility that CO2 forcing is not as high as the best guess, that the negative forcings have had less of a damping effect than has been assumed, that the sun has had a bit more of an effect, and cloud albedo and water vapour numbers, being as they are highly uncertain, favour the 'not as bad as they are saying' hypothesis.

What we can end up with (I'm neither advocating nor dismissing this), is a picture of recent human impact on climate which is less than half the 'assumed' amounts.

Add to this, that the estimate of climate sensitivity (how much warmer it will get if we double CO2) at the lower end of 2-2.5C.

Add to this, the estimates of sea-level rise, assuming no 'dramatic' change and using their number, is as likely to be 20cm in the next 100 years as the upper-end estimates of ~60cm.

Where do we end up? Somewhere close to many so-called 'sceptics' position on the AGW debate: By then end of the century, global average temperatures may well be a little less than 2C warmer than they are now. The sea will only have risen 8 inches. Though there are still droughts, hurricanes, melting ice-caps and the like, none of these exceeds our recent experience substantially. The net human input exists, but one part of it has largely been offset by another.

I would argue that this is a scientifically tenable and rational interpretation of the facts, physics and numbers as we have been given them by the IPCC.

No horror stories, no dramatic slide into chaos, no death by flooding or super-hurricane. Good reasons to consider where ocean-side development is viable or not, and good reason to support adaptive strategies by/for the most vulnerable nations. But would it be sufficient grounds to justify radical changes in energy policy? Probably not, though this wouldn't weaken the argument for change based on pollution issues. Reason enough to justify careful monitoring of the various systems and variables which come into play. Good reason to fund scientific research, as well as social/infrastructure investment.

Reason to panic? Absolutely not. Reason to fear that our world will change beyond recognition? Not really. Reason to be cautious about the long-term decisions we make? We always should be, anyway.

There's only one snag. In order to subscribe to this particular 'version' of the climate change future/AGW debate, it is necessary to accept that there is some human impact on the climate, that the solar impact is significant but not sufficient in itself, that the scientists aren't entirely wrong about the laws of physics. The only 'victim' of this version, really, are the climate models: they are seen to be at best rough approximators of possibility, rather than reliable indicators of most likely outcomes.

So, are there any people who have been pooh-poohed as 'sceptics' who are willing to subscribe to this version of 'scepticism, which does not deny climate change or AGW, but calls into question the assumptions about the extent and associated risks, calls into question the political motivations for action (they are worried about energy, not warming), call into question the Political/ethical conclusions being drawn without reference to the equal possibility of not much change occurring, but doesn't deny the fundamental science?

Thatis my back-of the-envelope effort at responding to the excessive panic and doom-mongering that AGW invokes. Any takers?

:)P

[Hiya]

Please read what I wrote. I said "I'd bet you can't find any evidence whatsoever for a prolonged 1500 year cycle with global temperature changes of 1-2C and solar output increasing by 3-4%.". OK? . Now you ask me to disprove something I'm asking for evidence of

Well Mondy sourced some information, and you expressed your doubt over it implying you thought it was not correct, I was wondering if you would be willing to show any data or referances to validate your doubt?

[parmenides3]

I knew this would come in handy one day:

'DOE events are noise'. A recent paper. Sorry about the file size.

doeventsarenoise.pdf

[pottyprof]

Why is solar activity not warming the Antarctic? This is often presented as a problem with the carbon emissions theory, but surely holds even more true for non anthropogenic causes.

Essan.. Can i refer you to a link here to explain that one??

http://www.netweather.tv/forum/index.php?s...st&p=937096

There is an interesting article here that explains in part, what happens when different cycles come together...

http://environment.newscientist.com/channe...ve-us-cold.html

[Roger J Smith]

Any discussion of future trends, whatever your perspective, should bear in mind that changes in the earth's surface will feed back into the atmosphere, so while one may very well correctly estimate various external factors such as several have done above, the net result on the atmosphere may not be a linear extrapolation of these factors.

To give one example, if there happened to be a winter of unusually heavy snowfall across North America and this snowfall persisted into late April or early May across large sections of the central regions, then temperatures would be greatly influenced by this no matter what the upper level flow or solar input or CO2 output happened to be during that period.

If this happened repeatedly for several years, it would lead to a marked change in annual temperature, and if it happened regularly for decades, it could trigger a circulation change on the order of an ice age. Some believe this is the type of event that actually triggers widespread climate change, a persistent anomaly within the bounds of normal climatic fluctuation that becomes self-reinforcing. I think the recent changes in climate in Europe related to SST anomalies in the Atlantic may fall into this category, and once created this feedback loop has no reason to dissipate until some new anomaly disrupts it.

Of course, if external forcing variables change sufficiently, such local variations are not likely to persist indefinitely, it would be like expecting an ice cube to remain intact in a pot of slowly boiling water, but we need to keep in mind that rather sudden variations can occur basically as the further results of one-time weather events. This certainly happens on the local or meso scale -- urban heat islands build up quite rapidly with urban expansion, local climates can become 2-3 C degrees warmer just because a location which may itself remain intact becomes surrounded by urban sprawl. This happened at Toronto airport between 1962 and 1968 when the airport weather station started to show much higher overnight temperatures due to the fact that the airport became gradually surrounded in that period of time by large industrial complexes and housing developments. The actual site and the terrain around it for say 200 metres probably didn't change that much, but the area became essentially urban rather than rural as previously.

A good example of climate feedback occurred in 1816 when, probably due to the 1815 explosion of Tambora, North American temperatures took a dramatic plunge in the spring and ice or snow persisted in the subarctic well into June. From records taken around James Bay, the effects were to prolong winter by 4-6 weeks over previous years. This was associated with freak weather events that year such as a snowstorm in New England on 5-6 June and several frosts in July and August in the Great Lakes region which killed off much of that year's harvest. These effects faded out of the climate records between 1817 and 1819 but one can see that if a larger volcanic eruption had perhaps led to even greater changes in the winter of 1815-16, this one-time event could have triggered even more massive changes in climate down the line.

[HighPressure]

Thatis my back-of the-envelope effort at responding to the excessive panic and doom-mongering that AGW invokes. Any takers?

:)P

Yes I can go with that as plausable and would not be a million miles away from my current thoughts.

[parmenides3]

Yes I can go with that as plausable and would not be a million miles away from my current thoughts.

I'm glad someone read it.

:)P

[pottyprof]

Interesting read there P3.. Food for thought perhaps..

And Roger too. The feedback loops are an important part of this..

If the sun then is more active, the heat build up would have less time to escape between energy bursts (not necessarily flares) so we become warmer.. ??

[Devonian]

Where do we end up? Somewhere close to many so-called 'sceptics' position on the AGW debate: By then end of the century, global average temperatures may well be a little less than 2C warmer than they are now. The sea will only have risen 8 inches. Though there are still droughts, hurricanes, melting ice-caps and the like, none of these exceeds our recent experience substantially. The net human input exists, but one part of it has largely been offset by another.

I would argue that this is a scientifically tenable and rational interpretation of the facts, physics and numbers as we have been given them by the IPCC.

No horror stories, no dramatic slide into chaos, no death by flooding or super-hurricane. Good reasons to consider where ocean-side development is viable or not, and good reason to support adaptive strategies by/for the most vulnerable nations. But would it be sufficient grounds to justify radical changes in energy policy? Probably not, though this wouldn't weaken the argument for change based on pollution issues. Reason enough to justify careful monitoring of the various systems and variables which come into play. Good reason to fund scientific research, as well as social/infrastructure investment.

Reason to panic? Absolutely not. Reason to fear that our world will change beyond recognition? Not really. Reason to be cautious about the long-term decisions we make? We always should be, anyway.

There's only one snag. In order to subscribe to this particular 'version' of the climate change future/AGW debate, it is necessary to accept that there is some human impact on the climate, that the solar impact is significant but not sufficient in itself, that the scientists aren't entirely wrong about the laws of physics. The only 'victim' of this version, really, are the climate models: they are seen to be at best rough approximators of possibility, rather than reliable indicators of most likely outcomes.

So, are there any people who have been pooh-poohed as 'sceptics' who are willing to subscribe to this version of 'scepticism, which does not deny climate change or AGW, but calls into question the assumptions about the extent and associated risks, calls into question the political motivations for action (they are worried about energy, not warming), call into question the Political/ethical conclusions being drawn without reference to the equal possibility of not much change occurring, but doesn't deny the fundamental science?

Thatis my back-of the-envelope effort at responding to the excessive panic and doom-mongering that AGW invokes. Any takers?

:)P

Don't often question you, P3, but this time I must. I'm probably thought of as a extreme 'warmer' by some, yet I can see 'just' 2C by 2100 as at least possible - being the 2-4C bloke I am. And I don't see either panic or doomongering in those like me. Tabloids are tabloids you expect tripe from them and, Ok, we've seen some articles in the better press mentioning what high end warming might cause, but that's something I would at least like to be aware of. But 'excessive panic and doom-mongering'? Where?

P3, do you think 2C would have minimal impact? I'm not so sure - perhaps you said that to avert cries that you're a doomonger . What would you think is serious? 3C?

[parmenides3]

Don't often question you, P3, but this time I must. I'm probably thought of as a extreme 'warmer' by some, yet I can see 'just' 2C by 2100 as at least possible - being the 2-4C bloke I am. And I don't see either panic or doomongering in those like me. Tabloids are tabloids you expect tripe from them and, Ok, we've seen some articles in the better press mentioning what high end warming might cause, but that's something I would at least like to be aware of. But 'excessive panic and doom-mongering'? Where?

P3, do you think 2C would have minimal impact? I'm not so sure - perhaps you said that to avert cries that you're a doomonger . What would you think is serious? 3C?

Dev: The 'alarmists and doom-mongers' label is often placed at the door of anyone who says that AGW is real. Of course it's unjustified. Saying that, it isn't a comment I made with anyone in mind, especially the NW regulars. But a traditional source of scepticism is the way in which AGW is 'oversold', both in the media, and in dialogues like the ones on this forum. My point is that a kind of scepticism can exist which is not a contradiction of the science, but a reaction to the conclusions which are reached, or jumped to, when the subject is discussed. To me, this is both reasonable and laudable. I find scepticism based on a denial of fact or known physical principles harder to deal with, and it tends not to be amenable to reason, as it is not based on a rational foundation.

As far as the impact of a 2C rise in global temps; I go along with the view that, whilst this will cause some changes which are undesirable, adaptation and mitigation at this level is both manageable and affordable, and doesn't require dramatic political intervention. It is likely that such changes would do some harm, but the harm could be manged and the victims helped, sometimes in advance, sometimes in retrospect (I'd prefer the former).

It also relates to the critical issue of the rate of change. Both human and biological systems are much more vulnerable to rapid changes than progressive ones. This doesn't mean that there wouldn't be some negative consequences to the ecosystem, but probably would imply that a 'mass-extinction event' is more unlikely.

I'd say a 2C rise is not, of itself, sufficient to cause a major reconsideration of the way we live in the developed world, which is something we often hear suggested. The 64 dollar question, though, is whether or not this is a scientifically tenable position, and whether such a comparatively small rise is more or less likely than, say, 3C or 4C.

How much is 'dangerous'? I'd say 3C (in less than 200 years) causes us serious issues; 4C would take us into unknown territory.

:)P

[Devonian]

Dev: The 'alarmists and doom-mongers' label is often placed at the door of anyone who says that AGW is real. Of course it's unjustified. Saying that, it isn't a comment I made with anyone in mind, especially the NW regulars. But a traditional source of scepticism is the way in which AGW is 'oversold', both in the media, and in dialogues like the ones on this forum. My point is that a kind of scepticism can exist which is not a contradiction of the science, but a reaction to the conclusions which are reached, or jumped to, when the subject is discussed. To me, this is both reasonable and laudable. I find scepticism based on a denial of fact or known physical principles harder to deal with, and it tends not to be amenable to reason, as it is not based on a rational foundation.

As far as the impact of a 2C rise in global temps; I go along with the view that, whilst this will cause some changes which are undesirable, adaptation and mitigation at this level is both manageable and affordable, and doesn't require dramatic political intervention. It is likely that such changes would do some harm, but the harm could be manged and the victims helped, sometimes in advance, sometimes in retrospect (I'd prefer the former).

It also relates to the critical issue of the rate of change. Both human and biological systems are much more vulnerable to rapid changes than progressive ones. This doesn't mean that there wouldn't be some negative consequences to the ecosystem, but probably would imply that a 'mass-extinction event' is more unlikely.

I'd say a 2C rise is not, of itself, sufficient to cause a major reconsideration of the way we live in the developed world, which is something we often hear suggested. The 64 dollar question, though, is whether or not this is a scientifically tenable position, and whether such a comparatively small rise is more or less likely than, say, 3C or 4C.

How much is 'dangerous'? I'd say 3C (in less than 200 years) causes us serious issues; 4C would take us into unknown territory.

:)P

Humm, yes OK . If it's just 2C by 2100 then the rate of change will also be slower - and rate of change does matter. But I think you're saying 2C will bring change but adaptable change - hopefully I guess. Not sure I think 2C not much of a problem but 3C serious, I wouldn't jump the emphasis so suddenly myself, you know, what about 2.5C? I'd prefer to say the greater the warming the greater the risk of ice sheets going, of permafrost melt feedback, or rain forest die back - I don't see a sudden 'beyond this it's serious' temperature. But, that said, my view is not far from your view.

[Mondy]

Pheww! Just logged back on.

Insightful posts from P3 and RJS.

Don't often question you, P3, but this time I must

Oh, come, come - now we have the pro-GW'rs questioning each other. Although to be very fair, P3 has posted some very interesting stuff from a naysayers POV and is to be praised for that.

Edited February 28, 2007 by Mondy