Interesting point of view (global warming debate)

[Jenksismyhero]

Hey Balta-

 

You seem to be the guy in the know with this (thanks for the earlier post btw, very informative). What causes natural rises in C02, like in the graphs posted above? Natural disasters (specifically volcanoes I'm thinking) or meteors or something?

[Balance]

Great posts, Balta!

 

I would encourage you all to watch "An Inconvenient Truth," regardless of what you think of Al Gore, politics, tree-huggers, and so on. It really explains this issue well. It really clarified and explained the issue for me.

[bmags]

science question...

 

is the water making up the ice caps ... different.

[Balta1701]

Hey Balta-

 

You seem to be the guy in the know with this (thanks for the earlier post btw, very informative). What causes natural rises in C02, like in the graphs posted above? Natural disasters (specifically volcanoes I'm thinking) or meteors or something?

All of those things can, to some extent, cause CO2 excursions, yes. Like many things that are worth time in science though, it is in fact a very complex matter, perhaps entertainingly so.

 

Meteors is probably the most obscure of those, so i'll just sort of touch upon that a little; it would take a really odd event to change the global CO2 budget, because they're such short lived things. Even if you burn every forest in the world, which may have happened in the Cretaceous impact, you only stick a transient pulse of CO2 into the atmosphere. So it's not really a big contributor to that.

 

Volcanic activity though appears to be able to have major effects on the earth's climate, in multiple ways, including CO2. There is in fact an average flux of CO2 from the mantle to the Earth's surface from volcanoes every year, and in fact, ever day. However, the Earth's system has adapted to this. Thanks to biologic systems and other feedbacks, it takes an awful lot of volcanism for volcanic CO2 to have a major impact on the climate in terms of warming, and even more importantly, volcanic activity spews more than just CO2 into the atmosphere. Single eruptions produce ash, high concentrations of sulfur, aerosol particles, and other things, which actually can go in the opposite direction of CO2. So, while an eruption like Tambora in 1815 almost certainly spat out a ton of CO2, the earth wound up having "The year without a summer" because of all the other junk that it spat out into the atmosphere.

 

If, however, you were to go through a massive, and I'm talking absolutely massive period of sustained volcanic activity, you might be able to jack up the CO2 enough to do some serious damage to life (especially considering all the other catastrophic things, like acid rain, that other volcanic gases can do). This may have happened roughly 2 or 3 times in the past 500 million years, specifically with the Siberian Traps and Deccan traps volcanic provinces which formed 250 and 65 million years ago, respectively. Both of them do correlate with mass extinction events, but we see nothing even close to their size active in the modern system (think about an amount of magma roughly 25 to 50 times the size of Hawaii being erupted in 1 million years or less).

 

But, neither of those really put a controlling effect on the graphs you're seeing above. They're very interesting geologically, but I'm getting sidetracked again.

 

The things that create that graph you see above, the ice-core (and other proxies) atmospheric CO2 record are things that operate on much shorter timescales and with much larger volumes of CO2 change. Specifically, we're talking about things that react to small climatic forcings; for example, the oceans, weathering, and vegetation.

 

There's another little issue I haven't brought up yet about that ice core variation record. Specifically, it seems to be controlled by atmospheric variations. If you do a fourier analysis on it and analyze the dominant frequencies controlling the variation over the last million years or so, a lot of them are close matches to orbital forcings. The eccentricity of the earth's orbit cycles on a 100,000 year timescale or so, the earth's axis wobbles on a 20,000 year timescale, and so on. These are the same numbers that we see in the climate system. But, if you do the simple "how much does the energy hitting the earth change with these cycles" calculation, the changes are no where near big enough to cause the starting and ending of large glaciations like we see.

 

What is actually happening though is that the much smaller shifts in energy wind up causing much larger shifts in the earth's climate because of feedbacks. This is where the CO2 comes in, along with a number of other issues. By shifting the amounts of solar radiation, the orbital forcings are able to shift the locations and sizes of things like the Gulf stream current, or the location and size of deserts, the amount of rainfall, etc. This can have enormous impacts on other systems.

 

First and foremost, the ocean itself responds dramatically to temperature changes. In fact, right now, with what we're doing to the atmosphere, the oceans are our biggest friend. Something like 1/2 of the CO2 man has actually released has been taken up by the oceans, because adding CO2 to the atmosphere can drive up dissolution of CO2 into the oceans. But, changes in global temperature can drive this cycle also; if you jack up the earth's temperature, you drive CO2 back out of the oceans and into the atmosphere (eventually, we do expect this cycle to catch up with the CO2 we've pumped into the oceans in the past 50 years, which is why climatologists will always say that there is more warming built into the system now even if we totally stop releasing CO2 right now).

 

Beyond that, changes in the atmosphere feed back strongly into plants and the terrestrial ecosystem as well. If, for example, you start making subtle changes in the climate, you can move vegetation north or south to areas that are larger or smaller, and therefore either lock up or release CO2 in that way. The Sahara desert, for example, towards the last glacial maximum, was much wetter than it is today, to the point that significant amounts of plant life thrived there. It has since dried up.

 

On top of that, the temperature and humidity of the atmosphere have profound impacts on the weathering of organic carbon. If you start to increase the temperature and therefore the humidity, you make it easier for the environment to degrade organic carbon and turn it into CO2, while in a lower temperature system it is easier to bury and sequester that same carbon, keeping it out of the atmosphere.

 

At least most of the evidence i've seen suggests that these sorts of feedbacks have been the dominant controls of CO2 content in the atmosphere over the last set of glacial cycles. There are a few other ways to change things (change production in the ocean, change ocean circulation patterns, change the earth's albedo by adding ice cover, change rock weathering rates, etc.) but those 2 are key, and it would take me forever to talk about all of them.

 

The one other issue you might notice I've sidestepped a little bit is that in both of those examples I gave, CO2 forcing was only accomplished in response to something else; you heat the oceans, then you get more CO2 out, or you change the temperature pattern and then you change CO2. But here we have a chicken-and-egg problem which I'm not sure has been resolved yet.

 

Because increasing atmospheric CO2 causes the earth to warm up, but warming up the earth can also increase atmospheric CO2, it's worth asking which one of them came first. The fact is, to some extent it is probably both. The small nudges that the orbital system produces pumps enough energy change (warming?) into the system to begin driving CO2 upwards for one of the many possible reasons, and the driving upwards of CO2 starts a feedback that keeps the planet warming until it finds some sort of new stable equilibrium after the glacial system falls apart.

 

However, what is happening right now thanks to man is, as far as we can tell, unprecedented within the last few million years. Not only have we increased CO2 to levels not seen anywhere in the last few million years, we have also jumped CO2 by over 30% within a period of a few decades, which may very well be an unprecedented change in earth history.

 

science question...

 

is the water making up the ice caps ... different.

In some ways, yes, it is quite different from what we see in the ocean. Specifically, isotopically it is very light. Through a process we call Rayleigh distillation, the snow that falls at the poles has a much lower concentration of heavy isotopes of hydrogen and oxygen in it than the rain that falls at the equator or the water in the oceans.

 

When ice caps form, this water locked up at the poles is actually so different isotopically that the isotopic composition of the normal ocean water changes in the opposite direction (The ice caps are very light, and as they get bigger, the ocean itself gets heavier). This produces one of the signals we see in the ice cores; as the isotopic composition of the oceans varies, the isotopic composition of the snow falling at the poles also is changed, and we can use these trends in the ice cores to track the waxing and waning of the ice caps. We can also confirm these signals with a variety of other proxies (none of which give the nearly annual resolution of ice cores), but anything which interacts with water and produces a preservable signal may well also show a similar pattern (a good example is microfossils that form from life in the ocean...you can take cores of oceanic sediments and see the same patterns you see in the ice cores. In fact, that is how the glacial cycles were identified before the ice cores were available.)

[bmags]

In some ways, yes, it is quite different from what we see in the ocean. Specifically, isotopically it is very light. Through a process we call Rayleigh distillation, the snow that falls at the poles has a much lower concentration of heavy isotopes of hydrogen and oxygen in it than the rain that falls at the equator or the water in the oceans.

 

When ice caps form, this water locked up at the poles is actually so different isotopically that the isotopic composition of the normal ocean water changes in the opposite direction (The ice caps are very light, and as they get bigger, the ocean itself gets heavier). This produces one of the signals we see in the ice cores; as the isotopic composition of the oceans varies, the isotopic composition of the snow falling at the poles also is changed, and we can use these trends in the ice cores to track the waxing and waning of the ice caps. We can also confirm these signals with a variety of other proxies (none of which give the nearly annual resolution of ice cores), but anything which interacts with water and produces a preservable signal may well also show a similar pattern (a good example is microfossils that form from life in the ocean...you can take cores of oceanic sediments and see the same patterns you see in the ice cores. In fact, that is how the glacial cycles were identified before the ice cores were available.)

 

danke.

[KipWellsFan]

canadafreepress.com... Universally recognized as a joke in Canada.

 

 

Denying climate change is like arguing that we were doing the blacks a favour by enslaving them.

[Texsox]

I think the debate isn't as much if there has been a climate change, we can prove that empirically. It is the cause and effect and what to do about it that is part of the debate and what makes science so interesting.

[Balta1701]

I think the debate isn't as much if there has been a climate change, we can prove that empirically. It is the cause and effect and what to do about it that is part of the debate and what makes science so interesting.

Scientifically, there's very little actual debate left right now about the cause part of that. We think we've got that part down pretty well. The questions now are the magnitudes of the impacts on all of the systems that interact with the climate, and yes, what if anything can and should be done.

[knightni]

Actually, Methane is another potentially severe greenhouse gas, possibly even more severe than CO2 because there's so little methane in the atmosphere right now.

 

Think of the environment, cork your ass.

[mr_genius]

Scientifically, there's very little actual debate left right now about the cause part of that. We think we've got that part down pretty well. The questions now are the magnitudes of the impacts on all of the systems that interact with the climate, and yes, what if anything can and should be done.

 

The big question, which is hard to answer, is how much of the temperature change is a natural cycle and how much is man made.

 

i think reasonable dissent in this, as any scientific debate, is good. any honest, competent, scientist will tell you the same.

[Balta1701]

The big question, which is hard to answer, is how much of the temperature change is a natural cycle and how much is man made.

 

i think reasonable dissent in this, as any scientific debate, is good. any honest, competent, scientist will tell you the same.

First of all, no, that is not the big question any more. That may have been the big question for science 15 years ago. For all practical purposes within the community that actually works on this process, the question is settled; the late 20th century warming trend is almost entirely a man-made phenomenon, and even the perturbations in it like the 1960's are due to specific actions by humanity.

 

I'm going to steal a few paragraphs from the recently released summary for policymakers of the 2007 IPCC report (keep in mind, this is a summary for policy makers, so every word here has specific, legalistic meaning, including the "Likelies"). Full report.

Most of the observed increase in globally averaged temperatures since the mid-20th century is very

likely due to the observed increase in anthropogenic greenhouse gas concentrations12. This is an advance since the TAR’s conclusion that “most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations”. Discernible human influences now extend to other aspects of climate, including ocean warming, continental-average temperatures, temperature extremes and wind patterns (see Figure SPM-4 and Table SPM-2). {9.4, 9.5}

 

It is likely that increases in greenhouse gas concentrations alone would have caused more warming than observed because volcanic and anthropogenic aerosols have offset some warming that would otherwise have taken place. {2.9, 7.5, 9.4}

 

The observed widespread warming of the atmosphere and ocean, together with ice mass loss, support the

conclusion that it is extremely unlikely that global climate change of the past fifty years can be explained without external forcing, and very likely that it is not due to known natural causes alone. {4.8, 5.2, 9.4, 9.5,

9.7}

 

Warming of the climate system has been detected in changes of surface and atmospheric temperatures,

temperatures in the upper several hundred metres of the ocean and in contributions to sea level rise. Attribution studies have established anthropogenic contributions to all of these changes. The observed pattern of tropospheric warming and stratospheric cooling is very likely due to the combined influences of greenhouse gas increases and stratospheric ozone depletion.

The data simply do not support in any way at present the suggestion that any significant amount of the recent, last 100 year warming trend is related to natural cycles. The science has moved well beyond that. The debate has now moved on to how big the impact of what man has done will be, not what fraction of it is due to man, because what man has done has already overwhelmed whatever natural variation could exist within the system.

 

Yes, Reasonable dissent is good. However, dissent for the sake of dissent, dissenting without solid evidence to back up one's case, accomplishes very little, especially in cases where politics get involved.

[mr_genius]

First of all, no, that is not the big question any more.

 

the article you have cited states it is a likely hood human emmissions are a main cause and that natural enviromental factors are not the only source. all true.

 

also, there have been huge climate changes on earth in the past and i've read of credible reports that state the main cause is probably due to human activity, but natural weather patterns cannot be ruled out. this may be difficult for you to accept, but it's a fact. suggestions that natural patterns may explain the weather changes should be tolerated.

 

having a debate with you on sceintific standards and respecting minority or oppsoing views on issues seems to be pointless.

 

the funny thing is we pretty agree on the global warming issue itself.

 

Yes, Reasonable dissent is good. However, dissent for the sake of dissent, dissenting without solid evidence to back up one's case, accomplishes very little, especially in cases where politics get involved.

 

 

politics is being played on both sides of this.

Edited February 8, 2007 by mr_genius

[Balta1701]

even the article you have cited states it is a likely hood human emmissions are a main cause and that natural enviromental factors are not the only source. all true. however, there have been huge climate changes on earth in the past and i've read a lot of credible reports that state the main cause is probably due to human activity, but natural weather patterns cannot be ruled out. this may be difficult for you to accept, but it's a fact.

Yes, the paper says it is "Very likely", but you didn't pay attention to what this report actually is; it is a summary for policymakers. In other words, it is not a scientific paper, nor is it a paper meant for public consumption without taking time to understand the language.

 

Saying that the things they have observed are "Very Likely" due to human activities is the strongest language they apply for anything in that paper other than it's predictions about future conditions, to which they apply the phrase "Virtually certain". This is language written by and for politicians to allow them to take action while still covering their bases. The SPM was actually vetted and to some extent rewriten by politicians from almost every country involved before it was released so that their governments would understand exactly the meaning of each word in it.

 

Yes, there have been huge climate shifts in the past. In the Cretaceous for example, atmospheric CO2 was something like 4 times the current values (which we could reach in a little under 200 years at current production rates). The climate was also on average roughly 8-15 degrees C hotter than it is today, as a consequence of the hightened CO2. Simply saying that there have been huge shifts in the past is not an argument that we have no ability to understand what caused those shifts, nor is it an argument that we have no ability to understand what our actions will have on the current climate. And most importantly, it is not an argument that rapidly changing OUR climate is not a bad thing. The earth can survive shifts of 15 degrees C. But that doesn't mean we as a civilization living on the earth want it to happen.

 

The fact is, we understand enough about the climate system to give you good estimates of the direction and magnitude of climatic shifts coming from rapidly dumping an additional 100 ppm of CO2 into the Atmosphere, and we are seeing the beginnings of exactly those effects showing up in the climate. This is the reality. The debate now in terms of the forcings is focusing on things like how much will specific areas warm up compared with others as the global average temperature increases, how much the total warming from the CO2 we have already released will be (that depends largely on cloud-feedbacks), what sort of impact it will have on ecosystems, why glaciers seem to be collapsing at much more rapid rates than we would expect from the current warming, and so on.

 

And finally, no matter what you have read, if you are reading things that are claiming that the current shifts are natural and not man-made, then what you are reading is simply not any scholarly work that has been published in the last 10 years. There simply has not been any published scholarly work in the last 12 years challenging the consensus view I gave from the IPCC report (which went from saying likely to very likely between 2001 and 2007 btw). A paper in Science a couple years ago took a look at that question, and found that there had not been a single published, peer-reviewed work in the last 10 years that had challenged the conclusion of the IPCC that most of the late 20th century warming was due to anthropogenic emissions. The evidence simply is not out there. The people doing this work know what they're doing, and there is simply no evidence being produced on the "it's all natural variation" or even the "anthropogenic emissions aren't the controlling factor" side any more. The community has moved on to more specific questions, and they did so quite a while ago.

 

This is not a question of respecting minority views any more, it's a question of there not being any credible views on the side you're claiming is the minority. The minority right now are people who say that yes CO2 is a major factor, but we'll only get 1.5-2 degrees C of warming in the next 100 years because of aerosol emissions or cloud increases (which is an entirely plausible conclusion)

Edited February 8, 2007 by Balta1701

[mr_genius]

like i said, i agree with you the main issue of global warming. you don't need to convince me.

 

but you are entirely incorrect that suggestions of natural climate change are not worthy of study and could not be a possibility. i'm not trying to be arrogant, but i don't think you understand what you are suggesting.

Edited February 8, 2007 by mr_genius

[Balta1701]

like i said, i agree with you the main issue of global warming. you don't need to convince me.

 

but you are entirely incorrect that suggestions of natural climate change are not worthy of study and could not be a possibility. i'm not trying to be arrogant, but i don't think you understand what you are suggesting.

I'm not at all suggesting it is not worthy of study on principle, I'm suggesting that there's no one publishing the statement you want for a reason. There simply is no evidence backing up that assertion, and studies which would have been expected to produce that sort of evidence if it were the case are done all the time in the process of analyzing recent climate shifts. I'm not saying "oh don't do this work", I'm saying that work which could prove the contrarian position, analyzing all sorts of recent climatic shifts and the driving factors behind them is done all of the time, and no matter how much work is done, nothing significant has come out which promotes any sort of challenge to the opinion that anthropogenic emissions are driving a strong warming of the Earth.

 

There is an awful lot of money available right now for research into things like the Little Ice age, carbon sinks, ways that the earth will react to dumping CO2 into the oceans that might mitigate atmospheric shifts, the response of organisms to rapid CO2 shifts, etc. But even with all that, no research of any major quality has come out saying that the climate shifts we have seen in the past 50-100 years are mostly natural. The evidence simply isn't there, and it's not for a lack of effort.

Edited February 8, 2007 by Balta1701

[mr_genius]

you're missing the point.

[Rex Kickass]

So is everyone else here.

 

Your point: people don't study whether climate change is purely natural.

 

His point: people study that all the time, the evidence just doesn't point to it.

 

That's kinda hitting your point on the head.

[mr_genius]

Your point: people don't study whether climate change is purely natural.

 

His point: people study that all the time, the evidence just doesn't point to it.

 

That's kinda hitting your point on the head.

 

no, it really isn't. some people are reaching the conclusion that some of the climate change is due to natural causes. they are in the scientific minority. being in the scientific minority doesn't automatically mean you're wrong.

 

i'm done with this argument, it is going no where fast.

Edited February 9, 2007 by mr_genius

[NorthSideSox72]

I think its about time the debate moves past this argument, and moves on to the now more important and relevant topic - what do we do about it, exactly? There are of course lots of ideas out there, but let's start studying which ones have the biggest impact, which are the cheapest or most efficient changes from a value perspective (so that we don't completely bankrupt businesses and countries), etc. And, even if we reduce man-made effects dramatically, it won't be enough to stop this thing cold (probably), so let's also start asking ourselves what we can do in response to the consequences that are pretty much inevitable at this point.