Anthropogenic Global Warming (AGW)/ "Climate Change"

[IndieHibby]

This is my first thread, so apologies if formatting is a mess:wink:

Q: "To what extent do man-made CO2 emissions influence the temperature of Earth?"

This question is designed to bring out people's opinions on the (media?) frenzy that is "Climate Change" a.k.a. 'Global Warming' and hopefully some of you may be able to contribute with some scientific basis for your arguments.

As is customary, I should state my opinion now;

As it stands, the extent to which recent trends in temperature can be explained by the added CO2 produced since the Industrial Revolution, is, IMO, limited.

I feel there is a great deal of correlation and little causation to back it up. There are other theories (sunspot activity, fluctuations in magnetic field strength/orientation), which seem more plausible, yet as they do not 'blame' something that can be controlled and taxed, have not taken the same signficance as AGW.

From what I can gather, the feedback mechanisms between CO2 and temperature seem to be slightly negative, which would suggest that temperature and CO2, although causally linked in theory, may have a more complicated relationship.

I ask as, among my peer group, I seem to be in the minority. I am interested in testing my opinion against hibs.netters, as, from what I have read, there are many posters here who take the time to have informed opinions.

So, am I suffering from a confirmation-bias induced blind spot over the 'evidence' behind 'climate change'? Or are my friends idiots?:devil:

[Woody1985]

I was watching TV last night and flicking channels. I watched 5/10 mins of something regarding the ice caps and there are scientists there who have been continually monitoring the melting and have testing of the oldest parts of the ice.

They've said that the changes they are seeing are so dramatic that if we don't act now we're basically ****ed.

The ice now melts 10 miles more inwards per annum than it did only a decade ago.

Rising sea levels etc and the effects of less land, less resources, food sources, increased populations etc will cause chaos in decades to come.

I watched something else a while back that the co2 levels in the sea were causing it to kill reefs where lots of sea life live. However, the planet appears to have a mechanism for cleaning itself (although probably not fast enough) by increased tornados out in the sea. The tornados suck up lots of water that then traps co2 from the air into the water.

Not sure exactly how it works but maybe someone can shed more light on it....

[Petrie's Tache]

I think that there was evidence of something like this happening in the world in the 1700's as doucumented in Captain Cooks logs whilst at sea. Showing a continuing trend in temperature increase. As at the time they wouldn't have coallated data from the polar ice caps then we can show no corolation to this, however that dosen't mean it didn't happen.

We need to look also at all the areas collectively as to where the temperatures are being taken and factor in for the increase in urbinisation as this itself will generate heat local to some of the temperature readings, thus "an increase in temperature".

My gut feeling and that is all it is. Is as we tend to see things in nature as cyclic events, this cycle has happened in the past and will happen again at some time in the future, whilst at no way do I discount the theory of CO2 emmissions are linked in some context I don't believe they are solely to blame.

At one point the emmission of CFC's was a major concern due to Cl- depletion of the ozone layer resulting in less protection from the suns radiation. Chemistry has shown, that the interaction of a Cl partical would breakdown the ozone compound (IIRC), again this could lead to a temperature increase within our atmosphere.

I feel alot of this is (and some may not like my views) propoganda generated by the US in order to stop the world using Oil as a major feedstock thus devaluing it as, TBH, they do not have the Lions share of the worlds largest currency and the stockpiles they have will be depleted in the near future (hence why the invasion of Iraq) therefore they need the buy in of the rest of the world in order to do so. What better way than scare the **** out of them? Al gore receiving the world peace prize is just another tool in this propoganda machine as many scientists have come out and spoken against this.

Long winded and probably not conforming with what most believe but at the end of the day that it s why it IMHO.

PS This only global warming, I will address the other theories by handing them over to Scotty.

[Twa Cairpets]

Good topic.

Whilst not having a defintive view on it, I think there are two or specific factors that suggest that climate change (which is a real and empirically measurable fact - the climate is changing) is a result of natural cycles being helped along by man.

The only two examples I can think of off hand are:

1) Cairn Toul, a mountain in the Cairngorms and the fourth highest in Britain, had a glacier (albeit a small one) at least into the seventeenth century. It now struggles to hold any snow through the summer. This little fact alone suggests to me that global warming (as opposed to climate change) is a natural phenomenon, but
2) I am sure I read (but cant find a link to back it up) that the hole in the Ozone layer has started to get smaller, and that there is strong evidence to suggest that this is linked to global reduction of CFC's in aerosols, fridges etc. This would suggest that changing mankinds behaviour can have a positive effect on atmospheric conditions.

My thought then is that as a species, we should be trying to do things better, cleaner and more efficiently because that is the right thing to do for many, many reasons. To base the bulk of environmental policy on carbon reduction efforts is needlessly focusing on a politically expedient headline. How many people really understand what a carbon footprint is? Makes a damn fine marketing line, but does it actually improve the world in any meaningful way?

[Sylar]

Q: "To what extent do man-made CO2 emissions influence the temeperature of Earth?"

This question is designed to bring out people's opinions on the (media?) frenzy that is "Climate Change" a.k.a. 'Global Warming' and hopefully some of you may be able to contribute with some scientific basis for your arguments.

It's extremely hard to quantify an extent to which man-made CO2 emissions are influencing the current global trend of increasing temperatures. At the end of the 17th century, the global temperature was much cooler, as we found ourselves in the midst of "The Little Ice Age" (this was the era when fairs on the Thames were regular occurrences). This lasted until the latter part of the 19th century when temperatures started to increase as we moved from the end of the cooling period, into the natural cyclical reverse of a warming period. This happened to coincide with the initial onslaught of the Industrial Revolution, where CO2 emissions began to skyrocket as developed countries began to mechanise production. As such, it's difficult to separate the trend of increasing CO2/increasing temperature. To assess how important the CO2 emissions were, I recently finished work on a paper which assessed the climatic data in the developing world, where the Industrial Revolutions of the Western World weren't influential and without going full-on into the data and discussions, the long and short outcome was that temperatures were rising all over the globe, but 9% slower where heavy industry was absent. Since reaching the status quo, many parts of the world have since, undergone heavy industrialisation, particularly India and China. At this point, it's hard to ignore the exponential increase in CO2 levels since the late 19th century and the consequential warming effect currently being experienced. I think your question is a tad misleading though, as CO2 is only a very small part of the puzzle - many other emissions are far more damaging in terms of their GW impact potential.

There's also the other side of the argument to consider, which is deforestation. Basic science tells you that plants absorb CO2 and prevent its exit into the atmosphere. We're actually doing an equal amount of damage by clearing vast areas of land, as we are in burning fossil fuels/using incomplete combustion during industrial processes. There's a strong correlation (pardon me, but I don't have the graph to hand) which illustrates the trend between CO2 levels, deforestation rates and global temperatures, which is hard to refute (I don't have the time to look, but if you go to the National Oceanic and Atmospheric Administration (www.noaa.gov) website, you'll find a good variety of data to support the argument.


As is customary, I should state my opinion now;

As it stands, the extent to which recent trends in temperature can be explained by the added CO2 produced since the Industrial Revolution, is, IMO, limited.

I feel there is a great deal of correlation and little causation to back it up. There are other theories (sunspot activity, fluctuations in magnetic field strength/orientation), which seem more plausible, yet as they do not 'blame' something that can be controlled and taxed, have not taken the same signficance as AGW

I think I tackled the first part of your opinion in the previous paragraph, so I won't repeat here. As for the other theories, yes, they are equally plausible, but don't have the regularity to account for the incremental increases we experience. Sunspot Activity can influence our global temperature (as well as our climate) but the level of activity needed to affect the entire global system with uniform impact is still unknown. The sun is more active now than it has been in the last 60 years, so the theory isn't entirely implausible. However, to refute it ever so slightly, in the 1970's, there was a disappearance in the previously understood correlation between solar activity and thermal properties, where solar activity remained constant, yet temperatures continued to rise. A paper by Solanki (2004) addresses the correlation between solar activity, volcanic activity and global temperatures much more eloquently than I can, if you're so inclined.

The geomagnetic/climate theory is a bit more complex. There is strong evidence to suggest that external magnetic signals are heavily correlated to significant climatic events (there was a rapid shift prior to Katrina for example), but this isn't a theory I personally subscribe to in any great detail. I do however, acknowledge that both geomagnetic variations and sunspots will impact on our climate, which is a very complex system, and not easily altered by one factor alone.




From what I can gather, the feedback mechanisms between CO2 and temperature seem to be slightly negative, which would suggest that temperature and CO2, although causally linked in theory, may have a more complicated relationship.



A picture is worth a thousand words I guess (see attachment):

This was a graph I include in my thesis, which addressed feedback mechanisms. Although there are anomalies in the data where annual feedback data does indeed suggest a negative correlation, for the most-part, the trend is very positive!

[Jack]

Something else that can be used as an excuse to tax people.

When I was at school in the 1960s I was told that by now, the early 22nd century, our climate in Scotland would be like the Mediterranean, I'm waiting ... sun tan lotion on. The reason given then was the worlds climate goes in cycles. There's no tax on cycles so the government had to think of another excuse.

The average temperature of the planet has been going up and down since it started spinning, taxing us to death in the nanofraction of the worlds existence we’re here isn’t going to stop that.

But it will raise important revenue keep a largely impotent armed forces* equipped and all the other things I really don’t need. (*With due reverence to the warriors themselves. If there's nothing they can do to defend me against random terrorists in central London, Glasgow and elsewhere with their mega million pound aircraft carriers or warplanes what's the point?)

While the major industrial countries around the world, India, China, Russia, USA continue to pump gazillions of everything into the planet, sea and air, anything the UK might do, to its less than 1% contribution, (including taxing me to death) will have absolutely no effect on climate change whatsoever.

But it will make me ever so cross at the muppets who say the end is nigh!

PS. I do recycle :greengrin

[Twa Cairpets]

It's extremely hard to quantify an extent to which man-made CO2 emissions are influencing the current global trend of increasing temperatures. At the end of the 17th century, the global temperature was much cooler, as we found ourselves in the midst of "The Little Ice Age" (this was the era when fairs on the Thames were regular occurrences). This lasted until the latter part of the 19th century when temperatures started to increase as we moved from the end of the cooling period, into the natural cyclical reverse of a warming period. This happened to coincide with the initial onslaught of the Industrial Revolution, where CO2 emissions began to skyrocket as developed countries began to mechanise production. As such, it's difficult to separate the trend of increasing CO2/increasing temperature. To assess how important the CO2 emissions were, I recently finished work on a paper which assessed the climatic data in the developing world, where the Industrial Revolutions of the Western World weren't influential and without going full-on into the data and discussions, the long and short outcome was that temperatures were rising all over the globe, but 9% slower where heavy industry was absent. Since reaching the status quo, many parts of the world have since, undergone heavy industrialisation, particularly India and China. At this point, it's hard to ignore the exponential increase in CO2 levels since the late 19th century and the consequential warming effect currently being experienced. I think your question is a tad misleading though, as CO2 is only a very small part of the puzzle - many other emissions are far more damaging in terms of their GW impact potential.

There's also the other side of the argument to consider, which is deforestation. Basic science tells you that plants absorb CO2 and prevent its exit into the atmosphere. We're actually doing an equal amount of damage by clearing vast areas of land, as we are in burning fossil fuels/using incomplete combustion during industrial processes. There's a strong correlation (pardon me, but I don't have the graph to hand) which illustrates the trend between CO2 levels, deforestation rates and global temperatures, which is hard to refute (I don't have the time to look, but if you go to the National Oceanic and Atmospheric Administration (www.noaa.gov) website, you'll find a good variety of data to support the argument.



I think I tackled the first part of your opinion in the previous paragraph, so I won't repeat here. As for the other theories, yes, they are equally plausible, but don't have the regularity to account for the incremental increases we experience. Sunspot Activity can influence our global temperature (as well as our climate) but the level of activity needed to affect the entire global system with uniform impact is still unknown. The sun is more active now than it has been in the last 60 years, so the theory isn't entirely implausible. However, to refute it ever so slightly, in the 1970's, there was a disappearance in the previously understood correlation between solar activity and thermal properties, where solar activity remained constant, yet temperatures continued to rise. A paper by Solanki (2004) addresses the correlation between solar activity, volcanic activity and global temperatures much more eloquently than I can, if you're so inclined.

The geomagnetic/climate theory is a bit more complex. There is strong evidence to suggest that external magnetic signals are heavily correlated to significant climatic events (there was a rapid shift prior to Katrina for example), but this isn't a theory I personally subscribe to in any great detail. I do however, acknowledge that both geomagnetic variations and sunspots will impact on our climate, which is a very complex system, and not easily altered by one factor alone.



A picture is worth a thousand words I guess (see attachment):

This was a graph I include in my thesis, which addressed feedback mechanisms. Although there are anomalies in the data where annual feedback data does indeed suggest a negative correlation, for the most-part, the trend is very positive!

:top marks Fantastic and clear response Scott. One question for you - if your thesis found that non-industrial countries had a smaller increase in temperature, does that suggest that industrial activity can have a local - as opposed to global - impact on temperature/climate.

[HibsMax]

Q: "To what extent do man-made CO2 emissions influence the temeperature of Earth?"

I think it's undeniable that man-made CO2 emissions have influenced climate change but to what extent, I don't know.

[Sylar]

:top marks Fantastic and clear response Scott. One question for you - if your thesis found that non-industrial countries had a smaller increase in temperature, does that suggest that industrial activity can have a local - as opposed to global - impact on temperature/climate.

I guess so, although this focussed on areas which were at significant distance to industrialised nations, not long after the onset of the Industrial Revolution. I think the easy answer is that any initial impact will be at a local scale, given time, will expand to regional and global, particularly if levels are not monitored or controlled.

There's always been a question as to how biased the global data is (as research is a luxury often only afforded to affluent countries who can afford it), but it does seem that given time, any impact with a consistent source will expand to larger scales.

[Petrie's Tache]

Scott is it conceivable that:


As non compressible particulates "solid buildings" obviuously these to have a compression co-efficient are built thus displacing the air particulates that once occupied that "compressible" air space. That if we look at the earths atmposphere as a "bubble" then there would be an increase of pressure globaly thus increasing the temperature based on the ideal gas law?

Wild I know and probably flawed beyond comprehension as it has been a long time.

[PeeJay]

Good topic.

1) Cairn Toul, a mountain in the Cairngorms and the fourth highest in Britain, had a glacier (albeit a small one) at least into the seventeenth century. It now struggles to hold any snow through the summer. This little fact alone suggests to me that global warming (as opposed to climate change) is a natural phenomenon, but ...

Interesting point about the Cairngorms TC. In the Alps the glaciers are also shrinking. Yet some studies suggest it's not only because of global warming, but because it snows less. Glaciers in the Alps recently studied, indicated that when they originally started to contract in the middle of the 19th century it was solely down to lack of snow in winter. (Geophysical Research Letters) (http://www.agu.org/journals/gl/ (mhtml:{E627484E-3699-42B0-852B-D59DCECE4A66}mid://00000306/!x-usc:http://www.agu.org/journals/gl/)). It wasn't until 50 years onwards that rising temperatures started to accelerate the shrinking process.
Although records show that the average temperatures in the Alps in the summers between 1760 and 1830 were warmer than the 20th century average - the glaciers did not shrink, in fact they actually expanded! The decades that followed however, saw the glaciers contract, despite summer temperatures dropping slightly. This problem is known as the paradox at the end of the Little Ice Age (http://en.wikipedia.org/wiki/Little_Ice_Age (mhtml:{E627484E-3699-42B0-852B-D59DCECE4A66}mid://00000306/!x-usc:http://en.wikipedia.org/wiki/Little_Ice_Age)) (1400 a.d. to 1850 a.d.) - during this period Europe generally experienced very hard winters. This phenomenon was examined in depth in the the French, Austrian and Swiss Alps by Christian Vincent and his colleagues at the Centre National de la Recherche Scientifique near Grenoble along with Switzerland's Martin Funk - they used winter poles dating fifty years back in time. These enabled them to draw conclusions on the changes in ice volumina. Old maps, aerial photographs and the location of end morain (http://en.wikipedia.org/wiki/Moraine#End_or_terminal_moraines (mhtml:{E627484E-3699-42B0-852B-D59DCECE4A66}mid://00000306/!x-usc:http://en.wikipedia.org/wiki/Moraine#End_or_terminal_moraines)) - i.e. ridges of unconsolidated debris deposited at the snout or end of the glacier - thus enabling the former dimensions of the glaciers to be accurately defined. The researchers compared the lengths of the ice flows with the temperature data and snow quantities for each year. Lack of precipitation details were compensated for by simulating glacial flows on the computer, whereupon they could then determine how much snow must have fallen for the ice flows to have occurred.

The researchers concluded that between 1760 and 1830 it snowed 25% more in winter than on average for the 20th century. From the middle of the 19th century onwards the glaciers started shrinkng again, because less snow fell in winter. They concluded finally that over the course of the past 100 years, global warming is the main contributor to glacial contraction.

[HibsMax]

Scott is it conceivable that:


As non compressible particulates "solid buildings" obviuously these to have a compression co-efficient are built thus displacing the air particulates that once occupied that "compressible" air space. That if we look at the earths atmposphere as a "bubble" then there would be an increase of pressure globaly thus increasing the temperature based on the ideal gas law?

Wild I know and probably flawed beyond comprehension as it has been a long time.

Sorry, I'm not Scott, but I think I know what you're asking. Human structures are taking up space that was filled with air and now this air has been compressed resulting in an increase in temperature. I don't have facts or figures or anything to back this up with but I feel fairly certain that the dent humans have put into the available volume of our atmosphere is miniscule.....statistically irrelevant perhaps.

But I too would love to know what impact this has had. Interesting point.

[ScottB]

I think to suggest the vast amount of gases we pour into the atmosphere has little or no effect on the planet is daft frankly. It's like saying pouring water into a glass won't fill it up.

The planet may be entering a natural warming cycle, and it has been through many such cycles before, the point is that our activities our amplifying the issue and making it happen at an increased speed.


In any case, we need to wean ourselves off of fossil fuels, if the fear of climate change is what does it, then so be it.

[Sylar]

Sorry, I'm not Scott, but I think I know what you're asking. Human structures are taking up space that was filled with air and now this air has been compressed resulting in an increase in temperature. I don't have facts or figures or anything to back this up with but I feel fairly certain that the dent humans have put into the available volume of our atmosphere is miniscule.....statistically irrelevant perhaps.

But I too would love to know what impact this has had. Interesting point.

I don't have any figures at all to verify or denounce this theory, but I'd be willing to assume that you're correct.

It's not something I've come across in any of my own research truth be told...

[HibsMax]

I don't have any figures at all to verify or denounce this theory, but I'd be willing to assume that you're correct.

It's not something I've come across in any of my own research truth be told...

I would imagine that things such as rising sea levels, mountain ranges rising and falling, etc. would have a greater impact.

The trouble as I see it is that humans are basically too selfish. Climate change is a growing concern but I believe that too many people think, "Oooo, that's bad.........but it's not going to be a problem in my lifetime, so whatever." (that's given me an idea for a poll). The danger is not imminent so therefor there is no urgency. I'm not saying everyone feels that way but when you have manufacturing plants around the world pumping tons of toxins into the atmosphere, you have to wonder. The number of people driving hybrid cars over here is increasing but it's still very slow. I am toying with the idea myself but (1) they are more expensive than petrol cars (booo!) and, (2) I am one payment away from actually owning my current car and I want to enjoy some time WITHOUT car payments.

It's kinda funny how we worry about such things. I think that we do have a little say in our own destiny but there's really not much we can do to alter the course that much. By "much" I mean in the grand scheme of things i.e., compared to the 4.5 billion years of earth's existence. Sure, we might screw things up a few centuries before they would have been screwed up anyway but what's a few hundred years between friends? ;)

I just hope that we learn enough important lessons on this planet so that when it's time for us to move somewhere else, we don't screw that place up too. Because like it or not, IF humans are going to continue as a species indefinitely, we're gonna need to find a new home sooner or later.

[Petrie's Tache]

Sorry, I'm not Scott, but I think I know what you're asking. Human structures are taking up space that was filled with air and now this air has been compressed resulting in an increase in temperature. I don't have facts or figures or anything to back this up with but I feel fairly certain that the dent humans have put into the available volume of our atmosphere is miniscule.....statistically irrelevant perhaps.

But I too would love to know what impact this has had. Interesting point.

As would I! However I feel it may be insignificant.

[da-robster]

I think climate change definately exists and humans are definately influencing it. I'm not sure by how much but we are and that needs to be changed quickly if we're not going to kill ourselves and others.

As for the government yes there taxing heavily but don't they always, if it wasn't climate change it would be something else.Although I bet most of that tax isn't going on climate change more likely on moats.

[BEEJ]

There's also the other side of the argument to consider, which is deforestation.

Basic science tells you that plants absorb CO2 and prevent its exit into the atmosphere. We're actually doing an equal amount of damage by clearing vast areas of land, as we are in burning fossil fuels/using incomplete combustion during industrial processes. There's a strong correlation (pardon me, but I don't have the graph to hand) which illustrates the trend between CO2 levels, deforestation rates and global temperatures, which is hard to refute

(I don't have the time to look, but if you go to the National Oceanic and Atmospheric Administration (www.noaa.gov) website, you'll find a good variety of data to support the argument.
For me, that's the most critical environmental issue for the world to deal with and has been for some time. The lungs of the planet are being systematically destroyed but the governments of the world seem incapable to act together to do something about it.

Far easier to lecture individual consumers about how best to calculate the CO2 consequences of buying that tin of pineapple chunks in Tesco's. :greengrin