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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

How about, instead of arguing over this-or-that feedback being +ive or -ive, we put our heads together in an attempt to create a picture on which we can all agree (stating any assumptions made)? :lol:

To me - in response to a hypothetical doubling of atmospheric CO2 - warming would be first? (assuming CO2 is a ghg?)

Said warming will allow the atmosphere to acquire/hold onto more water-vapour from evaporation? (+ive feedback?)

So, what happens next??

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Posted
  • Location: Worthing West Sussex
  • Location: Worthing West Sussex
How about, instead of arguing over this-or-that feedback being +ive or -ive, we put our heads together in an attempt to create a picture on which we can all agree (stating any assumptions made)? :lol:

To me - in response to a hypothetical doubling of atmospheric CO2 - warming would be first? (assuming CO2 is a ghg?)

Said warming will allow the atmosphere to acquire/hold onto more water-vapour from evaporation? (+ive feedback?)

So, what happens next??

Which warm moist air rises via convection, condenses* (releasing latent heat into the mid and upper troposphere, warming it there) into clouds, increasing albedo (-ve feedback) reducing insolation of the surface (-ve feedback), and precipitating the condensed water (and dissolved CO2 back to the surface, cooling the surface (-ve feedback) and feeding the land and ocean CO2 sinks.

*also absorbing the CO2 on the enormous surface area of the tiny droplets of cold water in the condensate.

But what warms the CO2 first, and where does the warming take place?

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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......
Which warm moist air rises via convection, condenses* (releasing latent heat into the mid and upper troposphere, warming it there) into clouds, increasing albedo (-ve feedback) reducing insulation of the surface (-ve feedback), and precipitating the condensed water (and dissolved CO2 back to the surface, cooling the surface (-ve feedback) and feeding the land and ocean CO2 sinks.

*also absorbing the CO2 on the enormous surface area of the tiny droplets of cold water in the condensate.

But what warms the CO2 first, and where does the warming take place?

I'd say that the poles will show warming first and they will have knock on effects throughout the globe. That said the tropical oceans will amass extra heat and feed that back through the ocean circulation currents we know of. Even without our adding a GHG in huge amounts natural warming on the scale we witness would lead (and has lead to) CO2 /Methane releases which seem to exasperate the situation.

Personally I would be looking for the loss of perennial ice (and a predominance of single year ice) across the north polar region and an associated feedback from the exposed 'dark waters' come summers end.

I would look for a north wards shift in the polar jet and a north wards movement of both the 10c ocean isotherm and rainfall distribution (along with storm tracks)

If you see any data reporting such I'd be worried :lol:

Edited by Gray-Wolf
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Posted
  • Location: Winchester
  • Location: Winchester

Perhaps we need to be careful not to be too fixed on a single sequence of feedbacks and have more of a branching tree?

I would argue that some of the warmer moister air might rise, but as the effect is small this would probably be overridden by local conditions and the warmth might be transferred to land/oceans/ice or just cause lower atmosphere air in general to be fractionally warmer?

on

what warms the CO2
my understanding is co2 gets excited to a higher energy state by absorbing a photon of incoming short wavelength em radiation (UV?) it then drops to a lower energy state emitting a photon of longer wavelength em radiation (IR?) which is more redily absorbed by other elements of the atmosphere so tends to increase the total energy contained within the atmosphere (including oceans) by delaying the emission of said energy to space
Which warm moist air rises via convection, condenses*

and while doing so also absorbs incoming solar radiation as above resulting in a positive feedback

and precipitating the condensed water

in some areas causing more moist air near the surface which absorbs incoming solar radiation resulting in a positive feedback?

Edited by trevw
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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.
Perhaps we need to be careful not to be too fixed on a single sequence of feedbacks and have more of a branching tree?

Yes Indeed, trevw...That sentence was what I was hoping for! :D

I think it's precisely this poorly-understood complexity that's dogging the whole subject? The average human brain just isn't capable of solving the resultant morass of simultaneous equations fast enough? Which is why computer models are the only potentially viable solution.

Do we try a 'critical path' type of analysis, with its necessary loss of detail; or attempt to build a truly representative picture? I think the latter is impossible? Being honest, I can't quite get my head round it! :D

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Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

As for the feedbacks from clouds... don't they cause lower daytime temperatures but higher overnight temperatures? In the UK excessive cloud cover tends to result in greater warmth in winter but greater coolness in summer.

Therefore, if it turned cloudier, could we end up with the poles getting warmer but the equator getting cooler? Also, it's open to debate whether a warmer climate would result in greater cloudiness overall- though cloud composition is affected by anthropogenic aerosols, the effects of which are uncertain.

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Posted
  • Location: Cheddar Valley, 20mtrs asl
  • Weather Preferences: Snow and lots of it or warm and sunny, no mediocre dross
  • Location: Cheddar Valley, 20mtrs asl
As for the feedbacks from clouds... don't they cause lower daytime temperatures but higher overnight temperatures? In the UK excessive cloud cover tends to result in greater warmth in winter but greater coolness in summer.

Therefore, if it turned cloudier, could we end up with the poles getting warmer but the equator getting cooler? Also, it's open to debate whether a warmer climate would result in greater cloudiness overall- though cloud composition is affected by anthropogenic aerosols, the effects of which are uncertain.

Depends entirely upon the type of cloud.

This was started a while ago but it ran out of steam:

http://www.netweather.tv/forum/index.php?s...=52522&st=0

Edited by jethro
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Posted
  • Location: Cheddar Valley, 20mtrs asl
  • Weather Preferences: Snow and lots of it or warm and sunny, no mediocre dross
  • Location: Cheddar Valley, 20mtrs asl

Came across this:

http://climatechange1.wordpress.com/

I've only had the briefest of scans, of the first couple of paragraphs, so don't shoot the messenger if it's tosh. Looks like it may be relevant to this discussion.

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Posted
  • Location: Rochester, Kent
  • Location: Rochester, Kent
Which is why computer models are the only potentially viable solution.

I agree. We need to use computers.

Climate modelling is, I suspect, a NP Complete problem. That is, there is no known analytical solution. One must yield to heuristic, genetic, neural, simulated annealing, or other approximation techinques to get a 'good' result - but it will never be the right result. Ever.

I note, with interest, that the mention of a hierarchy was used in an earlier post. A hierarchy, or tree, is a special kind of structure in mathematics, and, ultimately, in computer science, of something called a directed-graph, or, digraph, that has a special six point theorem of which I will not enter into here.

A digraph is known to have many problems the most famous of which is the travelling salesman problem. If you are using a substructure of a digraph, it is highly likely, given the complexity of the climate, that you will run into an NP complete problem that has already been classified as such in a different discipline.

Indeed, the travelling salesman problem may well be applicable.

That is not to say that we can't get good answers using other approximation techniques. It is only to say that whatever the answer its proof of success is measured in terms of probability and of inductive reasoning. In natural English - it will be close enough to count as a reasonable answer - but nothing more.

Edited by VillagePlank
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Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

Computer model accuracy is always going to be tricky to verify. The more assumptions we put into a computer model, the easier it will be to reach stronger conclusions, but the more likely it is that the conclusions will be based on false premises. And while we can verify how good models are at simulating the past, it is hard to devise ways of showing their accuracy at future predictions.

The accuracy of computer models is also bounded by the limitations of our knowledge of the atmospheric processes and how they interact with each other. And I agree with VP that there will never be a correct solution- it is hoped that we will get closer and closer with time, but even if we succeed our answers will only approximate to the truth.

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Guest North Sea Snow Convection

Very interesting - not tosh at all IMO. Mr Haap actually contributed to the stratosphere thread that I assisted chionomaniac with during the winter. He documents the intense polar stratospheric warming event of early this year in terms of it being an example of short term feedbacks at play as a consequence of it.

An honest assessment IMO - he admits that his thinking goes against mainstream AGW thinking, but that is a good and very necessary thing in order to get to the truth. From reading the link, I have picked some highlights (with bits in bold) which I think are very pertinent to the 'grey' areas of feedbacks - one's that are relegated by the mainstream science community who are striving to fit AGW as the primary driver of climate as a major priority. And which also highlight the weak and vulnerable areas for the IPCC. Solar energy is again stressed as a much larger natural driver than is given acknowledgent for.

The flesh on these bones is there to read - obviously I am not going to fill whole thread pages uneccessarily with the contents of the whole link!

The current post looks at temperature in the stratosphere in order to document how the vortex changes on ENSO and longer time scales thereby changing the basic parameters of the climate system. The climate system that we have today is essentially different to that of yesterday and what we will have tomorrow. Unless we understand that, we can not model it.

In relation to NASA’s comment “These changes are not enough to reverse the course of global warming” I can only say that NASA has to take off its cultural blinkers. Solar cycle 23 has already brought a re-adjustment of the climate system with markedly less tropical warming than cycle 21 and 22. The southern Oscillation is now more La Nina dominant. The cooling at high latitudes is underway. It is reported that high northern latitudes are experiencing a degree of cold that has not been seen since the 1970’s. All this is due to a recovery in the strength of the polar vortex as the intensity of UV radiation and the pressure of the solar wind has fallen away. As a result equatorial temperature at 10hPa, 100hpa and 200hPa has declined reflecting diminishing ultraviolet radiation. The atmospheric parameters are now close to what they were prior to 1978 with the prospect of further adjustment to come if solar cycle 24 is weak, as seems likely

Figure 7 confirms that an increase in average 30hPa temperature at the poles coincides with troughs in tropical stratospheric temperature. The relationship is systematic. This supports the hypothesis that episodic shift in the atmosphere weakens the polar vortex while increasing the atmospheric depth over the equator causing a fall in stratospheric temperature there. As a result, the zone of maximum ozone concentration over the equator must shift vertically upwards in response to atmospheric thickening. The collapse in temperature at 30hPa relates to the ascent of this ozone rich zone. The zone of maximum ozone concentration and temperature is displaced upwards and downwards according to the dictates of the solar QBO. This observation has profound implications for climatology. It is particularly relevant to the study of oceanic oscillations, change in surface temperature and understanding the natural mechanisms for long term change in climate. Any notion that the Earths climate can be properly modelled without an appreciation of this dynamic is illusory.

How far into the stratosphere does the reaction to outgoing long wave radiation that is evident at 100hPa extend? Ozone has been nominated as a greenhouse gas with respect to long wave infrared emissions from the Earth. It’s concentration at 100hPa is only 1-2 ppm by volume whereas the concentration of carbon dioxide in the atmosphere is 380 ppm by volume. A reactive gas absorbs radiation in a specific wave length and emits it at a different wave length, effectively scrubbing the absorbed wavelength from the spectrum of emissions. Ozone absorbs strongly at 9.6mm and 14mm. From the behaviour of the temperature curves in figure 2 it can be inferred that the infrared radiation from the Earth (in the specific wave lengths that excite ozone) is filtered out on first encounter with ozone in the upper troposphere and lower stratosphere. One would expect a similar layered filtering effect in relation to carbon dioxide depending upon the point of emission of OLR.

There is a lesson to be learned in relation to the posited greenhouse effect from the behaviour of temperature in the upper troposphere/lower stratosphere where OLR meets ozone. The energy gained at 100hPa due to the excitation of ozone by the Earths long wave radiation is not transmitted downwards. The outgoing long wave radiation peak at 100hPa occurs in August whereas the surface temperature peaks in May. (see figure 8 above) The May peak persists to the 200hPa level. The atmosphere itself therefore demonstrates that the posited downward transfer of energy does not occur. The countervailing force is the strength of convection. The greenhouse theorem is plainly unphysical.

flux in 200hPa temperature is plainly much greater than temperature flux at the surface. The series that is superior produces the surface temperature trend. The trend is downward within the green squares. There is a broad region of the upper troposphere between 400hPa and 100hPa experiencing strong temperature fluctuations unrelated to surface conditions. This affects ice cloud density. Flux in ice cloud density is hard to measure and the cloud is extensive. It is nevertheless the main mechanism responsible for warming and cooling of the tropical oceans. ENSO is the Pacific manifestation of this process. The warming is never uniform because the distribution of ozone in the upper troposphere is not uniform and is forever changing. It is much influenced by the solar wind and the response of the solar wind to the Earths magnetic field

Figure 10 records a long term decline in upper atmosphere relative humidity at the Equator and at 20-30°S. Plainly, cloud cover has suffered as relative humidity has fallen. Plainly, an increase in 200hPa temperature will produce clearing skies and warming seas. This pattern has intensified over the period of record.

Conclusion

Solar activity has weakened the vortex in both hemispheres. Periodic change in 200hPa temperature in response to changing ozone content and changing short wave radiation change ice cloud density and prevalence. This drives the Southern Oscillation. By and large it is the sea that stores energy and transports it to higher latitudes producing warmer winters. Ultimately sea surface temperature depends upon the Quasi Biennial Oscillation in ultraviolet radiation and the solar wind. The change in the solar QBO is responsible for the waxing and waning of the Southern Oscillation as it changes between El Nino and La Nina dominance.

Implications

Since warmer winters provide a longer growing season recent increase in winter temperature at high latitudes must be regarded as beneficial. That warming process is now reversing. If the sun descends into a deep minimum of ultraviolet and magnetic activity, all earth species will suffer.

The notion that carbon dioxide has caused a temperature increase is not supported by the climate record or observation of temperature dynamics beneath the tropopause. Limiting carbon emissions will do nothing to stem the course of solar driven climate change.

Modelling that begins with the assumption that influential parameters like ozone concentration, upper troposphere temperature and cloud cover are unaffected by solar activity, or that conditions in the troposphere are unaffected by QBO dynamics is devoid of value and has no utility whatsoever

Edited by North Sea Snow Convection
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  • 1 month later...
Posted
  • Location: Cheddar Valley, 20mtrs asl
  • Weather Preferences: Snow and lots of it or warm and sunny, no mediocre dross
  • Location: Cheddar Valley, 20mtrs asl

Here's an interesting, and in my opinion, well balanced view of the role oceans, clouds and ice play in climate:

http://www.nzcpr.com/guest147.htm

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Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

There is one problem I can see with the reasoning:

The inconvenient truth that is generally ignored, is that the atmosphere is not capable of warming the oceans to any significant degree – 99.9 percent of ocean heat is derived from sunlight at wavelengths less than 3 microns. The balance is mostly from heat leaking from the interior of the Earth.

That one seems dubious to me. For instance the North Sea SSTs warm up when it is warm over the UK for extended periods- as we saw in 2006/07 for example with those super-modified northerlies- so why can't the same happen over the world as a whole?

Concerning the feedbacks with clouds, what he presents (greater cloudiness = greater albedo = cooling of oceans) may be a bit simplistic for as per a post by Jethro above much of it depends on the type of cloud. Which cloud types would be likely to increase as a result of greater evaporation? In low to mid latitudes we'd probably see more convective clouds, at high latitudes simply more vigorous frontal cloud. However, by how much would they increase? It would be interesting to explore all of this in a computer model.

Many of the other points he makes appear sound, though some doubt can be cast upon the conclusions due to the warming up the oceans. I was particularly struck by his comment about the IPCC's worst-case figure being used in the economic analysis- that sort of misleading thing is all too common these days sadly.

Re. Gray Wolf's post on ice albedo feedbacks. It is likely that we'll see more melting in the Arctic causing continued warming of that region, but we also have to consider the possibility of cooling oceans nearby due to mixing with icebergs. And it is unlikely that we'll see any significant melting in the Antarctic- any rises in temperature will probably come together with increased precipitation, and the interior would need to warm by several degrees to make any major difference. And if polar ice cap melting caused runaway warming- how did we get ice ages start when there was hardly any ice cover at all?

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Posted
  • Location: Coventry,Warwickshire
  • Location: Coventry,Warwickshire

Firstly you need to be careful about mixing up climate processes and carbon cycle processes. Since most of the details mentioned so far are about climate processes lets just summarize some of these.

1) Melting polar ice reduces planetary albedo (light/heat reflected away from the earth) (Positive feedback)

2) Increase in desert conditions increases planetary albedo (negative feedback)

3) More low level cloud in the sub tropics increase planetary albedo (negative feedback)

4) More thunderstorms in the tropics causes heat to be absorbed (positive feedback)

5) QBO process (negative feedback). I am not entirely happy about including this not because the idea is substantially wrong, but the interaction between CO2 and Ozone in the stratosphere has not been properly explored.

Now I will include a few possible mechanisms not mentioned yet.

6) The boundaries of the Hadley and walker cells are shifted, changing the potential for mountain torque to change global angular momentum. It will also change the type and location of cloud cover.

7) Sun activity causes oscillations in the ionosphere which changes the reflectivity of boundaries lower down, which can affect the strength of the stratospheric polar vortex.

8) CO2 affects the amount of ozone.

9) Black soot deposited on ice reduces albedo.

10) Ocean transports slow or decline (deep water formation points change) this changes the distribution of heat in the sea, perhaps even melting sea ice.

11) There have been no recent major volcano eruptions.

Separate from climate is the very finely balanced carbon cycle. Just because we have tipped the balance one way does not mean there are feedback mechanisms which can either reduce or increase CO2 as a result. Some of these are listed below.

1) Warmer water shifts plankton production northwards where the oceans are narrower. Some argue that most of the increase in CO2 in recent decades may actually be due to this.

2) Plants are more vigorous in warmer conditions, absorbing more CO2.

3) Forest clearance reduces CO2 absorbance.

4) Acid rain changes plant and sea life so that less CO2 is absorbed.

5) Despite recent forest fires, forestry is much better managed these days and so there has been a reduction in fires.

Just a few ideas to mull over.

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Posted
  • Location: Worthing West Sussex
  • Location: Worthing West Sussex
Firstly you need to be careful about mixing up climate processes and carbon cycle processes. Since most of the details mentioned so far are about climate processes lets just summarize some of these.

1) Melting polar ice reduces planetary albedo (light/heat reflected away from the earth) (Positive feedback)

2) Increase in desert conditions increases planetary albedo (negative feedback)

3) More low level cloud in the sub tropics increase planetary albedo (negative feedback)

4) More thunderstorms in the tropics causes heat to be absorbed (positive feedback)

5) QBO process (negative feedback). I am not entirely happy about including this not because the idea is substantially wrong, but the interaction between CO2 and Ozone in the stratosphere has not been properly explored.

Now I will include a few possible mechanisms not mentioned yet.

6) The boundaries of the Hadley and walker cells are shifted, changing the potential for mountain torque to change global angular momentum. It will also change the type and location of cloud cover.

7) Sun activity causes oscillations in the ionosphere which changes the reflectivity of boundaries lower down, which can affect the strength of the stratospheric polar vortex.

:( CO2 affects the amount of ozone.

9) Black soot deposited on ice reduces albedo.

10) Ocean transports slow or decline (deep water formation points change) this changes the distribution of heat in the sea, perhaps even melting sea ice.

11) There have been no recent major volcano eruptions.

Separate from climate is the very finely balanced carbon cycle. Just because we have tipped the balance one way does not mean there are feedback mechanisms which can either reduce or increase CO2 as a result. Some of these are listed below.

1) Warmer water shifts plankton production northwards where the oceans are narrower. Some argue that most of the increase in CO2 in recent decades may actually be due to this.

2) Plants are more vigorous in warmer conditions, absorbing more CO2.

3) Forest clearance reduces CO2 absorbance.

4) Acid rain changes plant and sea life so that less CO2 is absorbed.

5) Despite recent forest fires, forestry is much better managed these days and so there has been a reduction in fires.

Just a few ideas to mull over.

I am extremely dubious about point 1, BF. Sea ice cover in the Arctic dramatically reduces at the end of the Arctic summer, when the sun has least chance to warm the open Arctic Ocean (c.f. June and July). The Arctic Ocean area uncovered by recent summer melts was briefly an anomaly of 3 million sq kM in 2007, about 2 million last year, both followed by somewhat remarkable recoveries, compared to the anomalies recorded since 2003. The total area of Arctic sea ice in any case is trivial as a reflector of solar radiation, compared even to temperate cloud cover, or continental European, Asian and American winter snowfields at lower latitudes.

Rather than a positive feedback, the open Arctic ocean of the last 2 years, radiating heat to space during the fading Arctic summer, probably represents a negative feedback in balance with more heat lost from warmer ocean compared to sea ice than the heat absorbed and not reflected by ice.

Similarly point 4. "causes heat to be absorbed"?? Tropical thunderstorms have high albedo, reach much higher above the surface than temperate or polar clouds, and represent a transport of surface heat into the upper troposphere, where there is much less chance of the heat being reradiated downwards. So not only does solar shortwave get reflected away at higher levels, heat transported from the surface is statistically transported into the upper parts of the atmosphere above the clouds as the top of the clouds spread and evaporate to the north or south of the tropics as mentioned in point 6. So this too is a negative feedback, rather than positive.

I also cannot agree with the statement "finely balanced Carbon cycle". Poorly understood maybe, because the accounts do not stand up to scrutiny - the role of winter ice on land in the northern hemisphere, and in the annual carbon cycle is not taken into account, neither are the areas of Arctic and Antarctic sea ice, which prevent large areas of cold water from absorbing atmospheric carbon dioxide. The so called "carbon cycle" is purely a computer model of the flow of carbon dioxide, with many flaws, basically little better than guesswork. Carbon sinks are apparently missing, or unknown, yet it is absolutely clear where atmospheric CO2 goes - it is precipitated together with rain, which is why rain has a normal pH of about 6.5, instead of a pH of 7.0 if it were pure water. In fact most temperate region rain is saturated with CO2, which destroys the myth that CO2 is a well-mixed gas - It may have a similar concentration 11,000 ft up a mountain to that measured by balloons and areoplanes, but it just gets mopped up by low clouds where they exist, and where the clouds aren't, like desert regions, the concentration builds at higher levels in the air, as many images from the AIRS satellites show. So annoying is this inconvenient fact to those who want to show that anthropogenic carbon dioxide is "polluting" the lower levels of the atmosphere, that they attempted to launch the Orbiting Carbon Observatory to image carbon dioxide nearer the surface than AIRS can. Sadly, the launch was a write-off.

If there is no evidence of a balance, there is no evidence of any tipping - it is a myth.

Another myth is ocean acidification, and coral bleaching due to carbon dioxide. Compared to the output of the odd volcano (of which you mention are not many majorly active at the moment) like the brief outburst by Kashatochi last year which released in a single explosion up to 10% as much SO2 as Pinatubo and a measurable quantity of bromine as the monoxide (rather bad for Ozone), and nearby Mt Redoubt which is still releasing large quantities of SO2 as it continues to erupt, 100 ppm increase of CO2/century on the acidity of seawater, is a drop in the ocean, literally. It is the carbonate and bicarbonate (i.e. dissolved CO2), together with divalent cations such as calcium and magnesium in sea water that keep the seawater buffered at an alkaline pH of about 8.1-8.2, despite strongly acidic anion moieties such as sulphite, sulphate, nitrate and chloride ions being constantly absorbed by the ocean from natural sources via the atmosphere.

We don't hear much about acid rain today, like we used to - the real threat was cleaned up by the oil companies, especially with regard to aviation fuel, where the aircraft released the SO2 directly into the troposphere. And when they had scrubbed the sulphur from the fuel, the temperatures went up. Positive feedback - less aerosols over the temperate NH, less cloud cover, lower albedo, temperatures increase. More flights, greater amounts of partially burnt long-chain hydrocarbons directly released into atmosphere, with much greater Greenhouse gas effects than even Methane, positive feedback, temperatures increase.

Currents shift to some extent due to the causes mentioned again in point 6, and are cyclical. The rate of spin of the earth is not constant, and not only does the length of day change, the rate of change alters too. Angular momentum must be conserved, because physics tells us so, and our fluid atmosphere, oceans and the earth's mantle react to these changes, in ways that geologists, oceanographers and atmospheric scientists are only just beginning to understand, and that climate modellers cannot yet dream of adding to their computer models. The cyclic fluctuations in plankton and thus the fish stocks, which have been recorded for centuries, and have little to do with recent fossil fuel use, but everything to do with Global Angular Momentum, cyclical variations in wind patterns, ocean current speeds and upwelling of fertile deep ocean waters from below the ocean thermocline, as well as the correlated climate pattern changes.

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Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk
Firstly you need to be careful about mixing up climate processes and carbon cycle processes. Since most of the details mentioned so far are about climate processes lets just summarize some of these.

1) Melting polar ice reduces planetary albedo (light/heat reflected away from the earth) (Positive feedback)

2) Increase in desert conditions increases planetary albedo (negative feedback)

3) More low level cloud in the sub tropics increase planetary albedo (negative feedback)

4) More thunderstorms in the tropics causes heat to be absorbed (positive feedback)

5) QBO process (negative feedback). I am not entirely happy about including this not because the idea is substantially wrong, but the interaction between CO2 and Ozone in the stratosphere has not been properly explored.

Now I will include a few possible mechanisms not mentioned yet.

6) The boundaries of the Hadley and walker cells are shifted, changing the potential for mountain torque to change global angular momentum. It will also change the type and location of cloud cover.

7) Sun activity causes oscillations in the ionosphere which changes the reflectivity of boundaries lower down, which can affect the strength of the stratospheric polar vortex.

:) CO2 affects the amount of ozone.

9) Black soot deposited on ice reduces albedo.

10) Ocean transports slow or decline (deep water formation points change) this changes the distribution of heat in the sea, perhaps even melting sea ice.

11) There have been no recent major volcano eruptions.

Separate from climate is the very finely balanced carbon cycle. Just because we have tipped the balance one way does not mean there are feedback mechanisms which can either reduce or increase CO2 as a result. Some of these are listed below.

1) Warmer water shifts plankton production northwards where the oceans are narrower. Some argue that most of the increase in CO2 in recent decades may actually be due to this.

2) Plants are more vigorous in warmer conditions, absorbing more CO2.

3) Forest clearance reduces CO2 absorbance.

4) Acid rain changes plant and sea life so that less CO2 is absorbed.

5) Despite recent forest fires, forestry is much better managed these days and so there has been a reduction in fires.

Just a few ideas to mull over.

brillant post just shows how complex our system is so it would be foolish to say artic ice will be gone in 10 20 years.

also foolish to dissregard a ice comeback either.

more time is needed but at the moment im just wondering how minimum the next couple of solar cycles will be,

this will be intresting times because i feel there is more to the gw than meets the eyes could go either way depending on what happens over the next 10 years or so,

and nobody knows the answer to this,

everything is just a prediction atm.

so doom for the arctic not yet although ofcoarse there be a couple that will dissagree.

but hey we see a slight fightback this year in regards to arctic ice.

and maybe where have record melts again this year,

but im sure its possible that it could return in the future. :)

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Posted
  • Location: Redhill, Surrey
  • Weather Preferences: Southerly tracking LPs, heavy snow. Also 25c and calm
  • Location: Redhill, Surrey

Perhaps we need to be careful not to be too fixed on a single sequence of feedbacks and have more of a branching tree?

The wine growing belt increases as temps remain warm. In turn more wine is produced and much of the demand is for white and rose, as temps soar so chilled wine is consumed in vast quantities. Fridges are turned to colder temps thus busting out more CO2, thus temps rise further and more wine is produced and......+ve feedback.

I'm off to the pub :doh:

Sorry I'll post sensibly next time Pete :D as it is a good thread to develop.

BFTP

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  • 1 month later...
Posted
  • Location: Dorset
  • Location: Dorset

I think this is the best place to put this.

http://news.bbc.co.uk/1/hi/sci/tech/8165223.stm

A few snipets below. I agree that clouds are an uncertainty but research like this really adds to the worry that the uncertainty has a good chance of falling down onto the "bad side" of predictions.

"Clouds over the North-East Pacific dissipate as the ocean warms, according to a study in the journal Science.

Researchers have described this as a "vicious cycle" of warming, as reduced cloud cover allows more of the Sun's rays to heat the Earth.

They say warming could gradually reduce the low-level cloud cover that is thought to help cool the globe.

But the team stressed that it was not yet possible to quantify how much this might impact on global temperatures.

They said that accurate simulations of these cloud effects would improve the models scientists use to predict future climate change patterns.

The accuracy of these models has been hampered by the uncertain influence of clouds on the global climate system.

The authors then tested leading climate models and found that only one - a model designed by scientists at the UK Met Office's Hadley Centre - reproduced this cloud effect.

This particular model predicts one of the more pessimistic climate change scenarios, with temperature increases at the high end of the range of forecasts. "

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Posted
  • Location: South of Glasgow 55.778, -4.086, 86m
  • Location: South of Glasgow 55.778, -4.086, 86m

A pretty poor report, constantly jumping back and forward from hypothesis to qualification of knowledge base.

"Basically, our approach was to take imperfect but independent data sets and add them together," – but does that make the science twice as reliable, or twice as unreliable?

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  • Location: Dorset
  • Location: Dorset

I can't see a problem with it personally. Any examples of why it's poor.

It's been peer reviewed, written by experts within their spheres, is a combination of visual and sat data etc etc.

"Because of inconsistencies in historical observations, trends in cloudiness have been difficult to identify. The team broke through this cloud conundrum by removing errors from cloud records and using multiple data sources for the northeast Pacific Ocean, one of the most well-studied areas of low-level stratiform clouds in the world. The result of their analysis was a surprising degree of agreement between two multi-decade datasets that were not only independent of each other, but that employed fundamentally different measurement methods. One set consisted of collected visual observations from ships over the last 50 years, and the other was based on data collected from weather satellites.

"The agreement we found between the surface-based observations and the satellite data was almost shocking," said Clement, a professor of meteorology and physical oceanography at the University of Miami, and winner of the American Geophysical Union's 2007 Macelwane Award for her groundbreaking work on climate change. "These are subtle changes that take place over decades. It is extremely encouraging that a satellite passing miles above the earth would document the same thing as sailors looking up at a cloudy sky from the deck of a ship.""

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

A pretty poor report, constantly jumping back and forward from hypothesis to qualification of knowledge base.

"Basically, our approach was to take imperfect but independent data sets and add them together," – but does that make the science twice as reliable, or twice as unreliable?

On the face of it, Penguin, it looks like a metastudy?

Surely, if all the previous reports were wrong (unless sytematically) mere addition of data would result in near-random scatter? That sensible results are yielded suggests, to me anyway, that said results are probably valid; open to scrutuniy and further testing yes, but valid nonetheless? :cc_confused:

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Posted
  • Location: Worthing West Sussex
  • Location: Worthing West Sussex

I think it's both hence why its a positive feedback mechanism :(

Then 'something' must stop the process from running away - since it doesn't get hotter and hotter, each time there is less cloud and a warmer ocean, what is it that stops the positive feedback?

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  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

Then 'something' must stop the process from running away - since it doesn't get hotter and hotter, each time there is less cloud and a warmer ocean, what is it that stops the positive feedback?

But, we're talking about one putative feedback out of many, Chris. And therin lies a problem: how do they interact. How, even assuming we ever isolate them, can we ever hope to untangle them?

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