Global warming

[iNow]

Folks should be careful about their haphazard use of the term "cycle." Just because climate varies does not mean it cycles.

 

Chris had a nice post on these issues just yesterday. He says it much better than I can:

 

 

http://chriscolose.wordpress.com/2009/07/02/cycles-projections-and-other-lingo/

 

1) Cycles: This follows the traditional “we’re in a cycle” line of thought. The justification was essentially that warmer and colder times happened before, and the co-worker reminded me of the ice core bubbles showing ups and downs in the past. I’m pretty sure she was talking about Milankovitch variations over the last million years. The term “cycles” in thrown around very loosely in these kind of discussions. So a few pointers:

 

• The term “cycle” has a precise statistical meaning. Just because climate changed before doesn’t mean “it’s a cycle.” The sun has a very clear cycle of roughly 11 years corresponding to changes in solar output, day-night variations is a cycle, there is a seasonal cycle, but in fact true cycles which affect the climate of the planet are not very common. Milankovitch are probably quasi-cyclical, but also not relevant for modern global change.
  
  
• Cycles are real physical phenomena, and thus if they change the Earth’s climate they did it in some real way, which needs to be defined. Seasons for instance are caused by the tilt of the Earth and the motion around the sun, while day-night changes are caused by the Earth’s rotation. Just saying “it’s a cycle” is not very useful: does this cycle happen to deliver the Earth more solar output, how long is the cycle, etc?
  
  
• Humans are a new part of the equation. Life can influence the climate. Plants and other organisms took an entire deoxygenerated atmsophere and put oxygen in it making it suitable for the life we know today. There should be nothing mystical about humans being able to change the climate, particularly as it’s easy to monitor changes in atmsopheric chemistry throughpretty emissions.
  
  
• Timescale matters: Milankovitch cycles influence climate on timescales of thousands to hundreds of thousands of years. Day-night cycles influence people on timescales of many hours, while seasonal variations influence people on timescales of months.
  
  
• Forcings on climate need to be added, not replaced. Different things can change the climate. If multiple things are changing, then you need to add them up, not pick which ones you like. If the sun is going up and CO2 is going up, you can’t just say “it’s the sun” because “it’s natural” or you don’t like humans or you like big yellow balls of fire, or whatever else. The influence of CO2 is very well defined and can be calculated with high accuracy (for the technical folk I’m just talking about the RF here, not the feedback component), and thus no physical justification exists for blaming it solely on “cycles” when cycles could only be adding or subtracting from the human-induced part of it, not replacing what CO2 does.
  
  

 

There are several other nice points at the link.

[bascule]

All respect to Dr. Mitchell K. Hobish, but I think he is being misleading at best.

 

You then go on to cite Steven Milloy... *facepalm*

 

Firstly it gives the impression that previous climate changes were slow and spread over thousands of years. This is totally false and frankly he should know that.

 

What? No, he's citing a case instance, and the same one you're trying to use to make a point.

 

Also since we now have a 30 year record from the satellites, it might be worth seeing what they say.

http://www.junkscience.com/MSU_Temps/UAHMSUglobe-m.html

 

Sorry, these graphs just suck, and I have to bring this up every time you post them. There is no legitimate reason not to include a five year mean, other than you want the noise to make the graph harder to read. I don't know whether to attribute this to incompetence or a malicious intent to deceive. How about a freaking trend line? Could I get that?

 

Seriously, there's no excuse. Here, about about you smooth the data out and provide a trend line:

 

 

Much better.

 

Would you say that the UAH MSU is showing "unprecedented" warming over the last 30 years? For that matter, would you say that they show even "unusual" warming?

 

In terms of what? Human history? Sure.

[JohnB]

What? No, he's citing a case instance, and the same one you're trying to use to make a point.

He's talking about 50 million years ago, which as I showed must have had vastly different circulation patterns and forcings compared to today. The thrust of his comment was to imply that natural climate changes only occur slowly over long time periods. This is false. Climate can change very rapidly over short time spans from purely natural forcings. "I don't know whether to attribute this to incompetence or a malicious intent to deceive."

 

Sorry, these graphs just suck, and I have to bring this up every time you post them. There is no legitimate reason not to include a five year mean, other than you want the noise to make the graph harder to read. I don't know whether to attribute this to incompetence or a malicious intent to deceive. How about a freaking trend line? Could I get that?

Okay, I'll give you that. I think that the graph is script generated from the MSU data, that's why I have to link to the page rather than the graph itself. Frankly, (not knowing scripts) I don't know if a 5 year smoothing and trend line can be added, but I would have thought that it could be done.

 

What did you think of my comments re internal forcings causing large scale changes? It's something I've been pondering on and would like your opinion.

 

Take your time. I'll be out of town for the next few days and not able to log on until about Friday, so there's no rush.

 

PS. I'd also like your thoughts on the UHI thread.

 

Cheers.

[bascule]

He's talking about 50 million years ago, which as I showed must have had vastly different circulation patterns and forcings compared to today. The thrust of his comment was to imply that natural climate changes only occur slowly over long time periods. This is false. Climate can change very rapidly over short time spans from purely natural forcings. "I don't know whether to attribute this to incompetence or a malicious intent to deceive."

 

Can you provide a case instance of comparably drastic climate change in the historical record? And I'm not talking about wild swings due to feedback loops which came from forcings manifesting over several centuries/millenia. I'm talking about when the earth was practically in an ice age and then swung into a rapid warming trend such as the one we're seeing in the course of a few hundred years.

 

What did you think of my comments re internal forcings causing large scale changes? It's something I've been pondering on and would like your opinion.

 

I don't know what you mean by "internal forcings"

 

Take your time. I'll be out of town for the next few days and not able to log on until about Friday, so there's no rush.

 

PS. I'd also like your thoughts on the UHI thread.

 

I'll check it out

[pioneer]

This past june in New England was one of the coldest on record, with the least number of sunny days since 1903. The reason this was so was because of constant clouds and rain.

 

Global warming will increase the amount of water in the atmosphere, since more water can dissolve into the atmosphere if surface temperature is higher. This leads to more clouds and less sunshine. Clouds are a good solar reflector keeping NE in the low 60's all June.

 

Is it possible the relationship between higher surface temperature and higher water content (more clouds) will make global warming self regulating? If there had been less water in the atmosphere over NE this past June, it would have been sunnier/warmer and more in par with the global warming predictions.

 

What was interesting, all this cool wet weather in NE, really made everything wild grow like weeds. It appears to have increased the surface area for CO2 absorption. Even algae, which is not normal on houses and roofs, during sunnier weather, is helping to collect CO2.

[bascule]

pioneer:

 

We're going through something similar, with extreme excesses of rain. It feels like we're living in Seattle. It's raining something like 6 days a week. We got more rain this June than the past 10 combined.

[bascule]

Sydney Australia has had a fair bit of rain this year as well, La Nina?

 

It's possible, although I haven't seen any scientist claim that as the cause of the excessive rainfall here.

[wufwugy]

Hi all,

on Milancovitch cycles... check out this graphic designer's nice movies on Youtube, "Climate denier CROCK of the week".

 

He has a bunch of the most recent denialist myths that are circulating the net, and he DEMOLISHES them. While he's a designer (hence the nice visuals in his youtube pieces) he has also been an activist for 30 years and hangs out with some of the climatologists he quotes. Anyway, to judge the quality of his work try this piece on Milancovitch cycles in the Crock "Temperature leads Co2". I thought he did a really nice job! I've subscribed to his Youtube channel and am now referring many of my online debates to him (saves typing it all out again, I'm lazy).

 

 

Yes, this is one of the best channels I've found. Thanks to donexodus for getting the word out. Sinclair truly is criminally undersubscribed.

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He's talking about 50 million years ago, which as I showed must have had vastly different circulation patterns and forcings compared to today. The thrust of his comment was to imply that natural climate changes only occur slowly over long time periods. This is false. Climate can change very rapidly over short time spans from purely natural forcings. "I don't know whether to attribute this to incompetence or a malicious intent to deceive."

 

I really want to see evidence and explanation for this. My impression to date has been that the current warming is several magnitudes more rapid that any natural trends found throughout geologic time

[iNow]

so.... what's up with the skeptics deniers?

 

There. Fixed.

[iNow]

It's late, and I can't think of anything off the top of my head, but my first search of the literature would surround these questions:

 

1) There is a greater population in the northern hem than the southern, so is it that CO2 is more concentrated over more densely populated areas? How quickly do the CO2 contributions find "equilibrium" and disperse evenly across the globe? Does the rate of this dispersion outweigh the rate at which we add new CO2 over populated areas?

 

2) Axial tilt... is the Northern hemisphere tilted more toward the sun than the southern?

 

3) What are the differences in northern hemisphere ocean currents and southern hemisphere currents, and what are their respective impacts (and the magnitude of that impact) on hemispheric temperature averages?

 

 

Chances are good that the answer to your question lies in the answer to one of mine. Enjoy your night, friend.

[wufwugy]

I really want to see evidence and explanation for this. My impression to date has been that the current warming is several magnitudes more rapid that any natural trends found throughout geologic time

 

Does anybody have a response to this? This is important because if it's true that the current warming is substantially faster than any other 'natural' warmings throughout history, then we have our smoking gun for AGW.

 

Well, there's a lot of smoking guns for AGW, but this would be a big one

[swansont]

Does anybody have a response to this? This is important because if it's true that the current warming is substantially faster than any other 'natural' warmings throughout history, then we have our smoking gun for AGW.

 

Well, there's a lot of smoking guns for AGW, but this would be a big one

 

This suffers from the same shortcoming as the "it's been warmer in the past" argument, though. Just because (if) it hasn't happened before isn't sufficient. It's not a smoking gun if there's a mechanism which would account for he warming.

 

But there doesn't appear to be any mechanism other than CO2, as far as I am aware.

[Baby Astronaut]

Anyone into physics help me with the following then? (I've lost the original thread where I asked these questions about Co2 physics, sorry.)

Might be in either of the following posts by you.

 

http://www.scienceforums.net/forum/showthread.php?p=368897&highlight=Co2+physics#post368897

 

http://www.scienceforums.net/forum/showthread.php?p=384198&highlight=Co2+physics#post384198

 

Cheers!

[alex folen]

it's a little warm today in Florida.

[wufwugy]

This suffers from the same shortcoming as the "it's been warmer in the past" argument, though. Just because (if) it hasn't happened before isn't sufficient. It's not a smoking gun if there's a mechanism which would account for he warming.

 

But there doesn't appear to be any mechanism other than CO2, as far as I am aware.

 

Well yes, understanding the mechanism and proving warming in the first place is more important, and we do already have those.

 

If warming is dramatically faster now than ever before it is a very big deal though since the likelyhood of warming being anthropogenic shoots through the roof since pretty much the entire history of the planet is a control against current human activity.

[JohnB]

Sorry for the delay, but I've been away.

 

I don't know what you mean by "internal forcings"

I mean internal, rather than external forcings. Volcanic plumes, Solar changes and CO2 from fossil fuels classify as external forcings. Changes (for example) to cloud coverage due to the natural evolution of the planet would classify as internal. As the sea level rose after the last Ice Age, ocean circulation would have changed, thereby changing other factors. This is "internal" forcing.

 

And the climatologists know what forcings those trends were caused by, have accounted for them all (pretty much) and so.... what's up with the skeptics?

 

Sorry, but no. I'm aware of and have read papers outlining, 3 different theories for the Younger Dryas period. These all appear to be pretty much mutually exclusive, so the cause is still very much up in the air ATM.

 

The cause(s) of the Dansgaard-Oeschger warming events that occur at 1470 year intervals is (are) also unknown. A rather interesting GRL paper on the topic by Stefan Rahmstorf is here. Nor do we know the cause(s) of the abrupt change circa 8.2 KBP or the cause(s) of the changes circa 5 KBP.

 

(Dr Karl's a generalist and lately more of a media liaison and science reporter).

 

Isn't his main "claim to fame" researching why belly button lint is blue? Or is that a different radio presenter?

 

You are aware that sea level rise is not a recent event, aren't you? Sea levels have risen some 150 metres since the end of the last Ice Age.

 

Actually, measuring Holocene sea level rise is another interesting topic. Between the isostatic rebound found near past glacial areas and actually working out the measurements, it's very complex. A fascinating subject. In some areas it goes up and in others it goes down.

 

Morner et al 2004 for example finds a sea level drop in the Maldives of nearly 30cm over the last 30 years or so. To be fair, Church et al 2006 finds no evidence of the drop. They do find though,

For 1993 to 2001, all the data show large rates of sea-level rise over the western Pacific and eastern Indian Ocean (approaching 30 mm yr− 1) and sea-level falls in the eastern Pacific and western Indian Ocean (approaching − 10 mm yr− 1).

Like I said, fascinating.

 

I really want to see evidence and explanation for this. My impression to date has been that the current warming is several magnitudes more rapid that any natural trends found throughout geologic time

Unfortunately for your "smoking gun" idea, the current warming is several magnitudes lower than some previous warmings and coolings.

 

The exit from the Youger Dryas period for example was a temp rise of around 15 degrees over a mere 50 odd years. Now that is from The GISP2 cores in Greenland so we can expect some high latitude amplification. However that would still mean some 3-5 degrees in lower latitudes. Somehow I think that 3-5 degrees over 50-70 years is a bit faster than the current .7 degrees over a century.

 

If you're interested in that period, papers by Dr. Richard B. Alley are a good start. He's involved in the GISP cores and his papers are very readable and clear. (Even to the untrained like me.)

 

wufwugy, part of the disagreement is that to believe that current warming is in some way "unprecedented", you have to deny the existence of of earlier periods of warming and cooling like the Little Ice Age, Roman Warm Period or the Medieval Warm Period. You have to believe that Bristle Cone Pines in California are good and true indicators of the planetary temperature.

 

It's hard to point with alarm at the shrinking Alpine Glaciers if you accept the scientific evidence that they have grown and shrunk something like 5 times in the last 2,000 years.

 

The only way to scare people with horror stories about what will happen in the future if temps rise another degree or so is to ignore the evidence that it was warmer in the historical past than it is now, and the world didn't end.

 

To quote from the abstract of Carlo Giraudis 2005 paper "Middle to Late Holocene glacial variations, periglacial processes and alluvial sedimentation on the higher Apennine massifs (Italy)"

 

Around 5740-5590, 1560-1370 and 1300-970 cal yr B.P., organic matter-rich soils formed on slopes currently subject to periglacial and glacial processes; the mean annual temperature must therefore have been higher than at present.

(Emphasis mine)

 

You may also like to read Mayewski et al 2004.

Examination of these records demonstrates that, although generally weaker in amplitude than the dramatic shifts of the last glacial cycle, Holocene climate variations have been larger and more frequent than is commonly recognized.

 

Climate changes, always has and always will. As I pointed out earlier in this thread, this interglacial is unusual, in that rather than peaking and dropping, the temps have bounced up and down by around 4 degrees for the last 10,000 years.

 

As to why the Northern Hemisphere warms faster than the Southern, I think iNow has probably got it with his questions.

 

Cheers.

[iNow]

I really want to see evidence and explanation for this. My impression to date has been that the current warming is several magnitudes more rapid that any natural trends found throughout geologic time.

Unfortunately for your "smoking gun" idea, the current warming is several magnitudes lower[/b'] than some previous warmings and coolings.

 

Hey John - It seems to me that he was referring to the rate of warming, not the amount, which makes your reply off-point. Cheers, mate.

[wufwugy]

 

 

Unfortunately for your "smoking gun" idea, the current warming is several magnitudes lower than some previous warmings and coolings.

 

The exit from the Youger Dryas period for example was a temp rise of around 15 degrees over a mere 50 odd years. Now that is from The GISP2 cores in Greenland so we can expect some high latitude amplification. However that would still mean some 3-5 degrees in lower latitudes. Somehow I think that 3-5 degrees over 50-70 years is a bit faster than the current .7 degrees over a century.

 

If you're interested in that period, papers by Dr. Richard B. Alley are a good start. He's involved in the GISP cores and his papers are very readable and clear. (Even to the untrained like me.)

 

wufwugy, part of the disagreement is that to believe that current warming is in some way "unprecedented", you have to deny the existence of of earlier periods of warming and cooling like the Little Ice Age, Roman Warm Period or the Medieval Warm Period. You have to believe that Bristle Cone Pines in California are good and true indicators of the planetary temperature.

 

It's hard to point with alarm at the shrinking Alpine Glaciers if you accept the scientific evidence that they have grown and shrunk something like 5 times in the last 2,000 years.

 

The only way to scare people with horror stories about what will happen in the future if temps rise another degree or so is to ignore the evidence that it was warmer in the historical past than it is now, and the world didn't end.

 

To quote from the abstract of Carlo Giraudis 2005 paper "Middle to Late Holocene glacial variations, periglacial processes and alluvial sedimentation on the higher Apennine massifs (Italy)"

 

 

(Emphasis mine)

 

You may also like to read Mayewski et al 2004.

 

 

Climate changes, always has and always will. As I pointed out earlier in this thread, this interglacial is unusual, in that rather than peaking and dropping, the temps have bounced up and down by around 4 degrees for the last 10,000 years.

 

As to why the Northern Hemisphere warms faster than the Southern, I think iNow has probably got it with his questions.

 

Cheers.

Okay, glad to see your response. Now that I have your attention, I think I can further clarify my position.

 

It's not just about rate of change now verses any other time in history. It's about comparable circumstances. IOW, we cannot compare the rate of climate change on the Earth when it was either really hot or really cold or when from some obscure event to now due to the subjects simply just being different. It's like how we can't compare the medical condition of a healthy person to that of a diseased person. In order to study our current rate of warming we will need to compare to similar times in geologic history, as well as isolate causes. Times like the Younger Dryas are not that applicable due to being much different than current times. Also, I think it is thought that the Younger Dryas began long before rapid climate change happened.

 

I'm not willing to research this myself because it will take a TON of diligent study since the answer is predicated on much more elaborate understanding than I currently wield. What I am looking for is somebody who already knows what's up who can point to the results of studying rate of changes in climates and due to reasons comparable to current.

 

I'm not sure how well I'm getting my question across. Basically, it has to do with understanding the causes of climate change in times similar to our current Earth, and being able to compare the causes and rate of change to our current Earth. Understanding that would go a long way in determining exactly how much of an impact anthropogenic activity has on the our climate.

 

Anyways, I've realized that this topic is a very complicated one that would require doctorate levels of understanding in order to even begin clarifying. I'm just struck by the fact that we've only just begun burning fossil fuels, and yet have seen pretty dramatic warming. My ideas of climate change phases throughout history are that they are at least thousands of years in the making before real change begins to kick in. We're only in the introductory stages of changing oceanic and atmospheric GHG ratios, yet we're already seeing rapid change. That's what makes me think that this could be a smoking gun

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Hey John - It seems to me that he was referring to the rate of warming, not the amount, which makes your reply off-point. Cheers, mate.

 

Naw, he understands that as shown by his Younger Dryas analogy. I just suspect that its a misunderstood analogy

[JohnB]

Hey John - It seems to me that he was referring to the rate of warming, not the amount, which makes your reply off-point.

So you don't think that warming 3 degrees in 50 years is a faster rate of warming than .7 degrees in 100 years? How on earth do you do your taxes?

 

wufwugy, if you are not willing to go and read the links, then you won't learn anything. The Younger Dryas did not begin "long before rapid climate change happened", it is defined as a period of rapid climate change.

 

The problem is that you can't define what you mean by "times similar to our current Earth." Is 5,000 years ago too long? We're talking about change during the Holocene, the time since the end of the last Ice Age.

 

Do you mean times when the temps were similar to what they are now? Since the temps have gone up and down, do you want a period when they were about the same as now and going up? Or about the same as now but going down?

 

My ideas of climate change phases throughout history are that they are at least thousands of years in the making before real change begins to kick in.

Then your ideas are wrong. Period. If you aren't willing to read the links and find that out, you will not find the answers to your questions. It really is that simple.

 

I'm just struck by the fact that we've only just begun burning fossil fuels, and yet have seen pretty dramatic warming.

Yet when we look at the climate record, "pretty dramatic" describes many of the changes. The current warming is, either by rate of change or amount of change not unusual by any standard.

 

We're only in the introductory stages of changing oceanic and atmospheric GHG ratios, yet we're already seeing rapid change.

Since rapid change occurs very often in the record, it would be unusual for there not to be a change associated with something mankind does. Correlation does not imply causation.

 

Put it another way. Shortly after the introduction of gunpowder into Europe, the temps dropped the Earth into the Little Ice Age. Would you argue that the increased smoke from gunpowder weapons caused the Little Ice Age?

 

We also know that there was a major shift in around 3,100 BC causing the Saharan oases to dry quickly, leading to those people migrating to the Nile region to become the Pharonic Egyptians. This is less than 200 years after the invention of the wheel. Did the invention of the wheel cause rapid climate change?

 

Naw, he understands that as shown by his Younger Dryas analogy. I just suspect that its a misunderstood analogy

I guarantee I understand more about the YD period than you do. Analogy my foot. You asked for times when the rate of change was similar to or greater than todays and I gave you one. The entry and exit from the YD were greater in both magnitude and rate than the paltry changes seen today.

 

This is true for all the DO events outlined in the linked to Rahmstorf paper. If you bothered to actually look at the evidence provided you would know that.

 

Do you want facts or cherry pie?

[wufwugy]

Thanks for the response. I too guarantee that you understand this stuff more than I do. Also, I read the link, as well as the wiki on Younger Dryas, I just don't comprehend them that well.

[JohnB]

Actually, the YD event is very interesting in it's own right. Each of the competing theories fit some but not all of the observed facts. I'm sure we'll puzzle out the cause one day, but what that cause will be, I think your guess is as good as mine.

[hemantc007]

hey..........sustainabilit ...i have a video in which they showed that due to global warming ,ice has started melting ,due to which polar bear don't get a land form to hunt and survive .........they have to take risk of hunting other animal which are dangerous and many time they die or starve to death

((this sucks,... people are not bothering about this, animals are also living they are alive and we do not have any right to kill them, wake up man.........this is disgusting ))

...........it is quite sad that still people are not bothering about this,..........this efect our eco-system ,thus effecting every one on this planet ........if there will be more ice melting in future then the level of sea will rise to a hight that million of people will die , many island will be submerged in sea ....there will be disaster all around but it will be slow but indeed affective ....................i try my best for conservation of fuel,water . prevent pollution as much as possible and also spreading inf amoung people...........

wakeup don;t be so dum do some thing or at least don't do such things which indirectly affect the nature............and life.!!!!!!!!!!!!

[insane_alien]

can you type like a normal person please. your posts are very difficult to read like that.