Stark warning over climate change

[bascule]

http://news.bbc.co.uk/1/hi/sci/tech/4660938.stm

 

This article deals largely with the melting of the Arctic ice sheet. Throughout the entirety of the article, the cause is attributed to global warming. This is one of innumerable stories which have been published throughout the past few years drawing the connection between global warming and melting Arctic ice.

 

But wait a second, what about Antarctic ice? If global warming is the problem, why don't we hear anything about that? The answer is because there is no progressive trend in summer ice coverage in the Antarctic, only aimless fluctuation.

 

Now, ask yourself: if global warming is the problem, why is the ice sheet of one pole melting while the other one stays more or less the same? Shouldn't we see symmetric effects in how the different hemispheres of earth are affected, if the problem is truly the result of changes in the global climate system, ostensibly the result of greenhouse gasses (which is the point the linked article tries to drive into the ground)

 

My reaction? This is a correlation vs. causation fallacy. There is a regional warming effect occuring in the northern hemisphere which is not occuring in the southern hemisphere. This is not a global problem. It is a regional problem, and should be dealt with as such. Something like Kyoto will not have an impact on the melting of the Arctic ice sheet.

[Sisyphus]

I don't know much about meteorology, but isn't the northern hemisphere somewhat isolated from the southern, as far as weather patterns are concerned? And if so, you wouldn't really expect the effects of, say, manmade emmisions in the northern hemisphere to have an equal effect in the southern, would you? At least not in the same time frame?

[john5746]

I need to educate myself on the subject further, but:

 

1) The Antarctic ice is primarily on land, Arctic is on water. If the ice is melting due to warmer water, I would expect the Arctice to thaw first.

 

2) Weather is complex. I wouldn't expect the whole earth to warm everywhere at the same time.

[m4rc]

Global warming is melting as much ice in the south as in the north. The reason there are more news reports about the arctic ice is that more people live near the north pole.

I do remember reading several articles about the ice shelf in antarctica melting as well. For example http://www.newscientist.com/channel/earth/dn8173 states that "The edges of the Antarctic ice sheets are slipping into the ocean at an unprecedented rate" (oct 2005). I also remember news stories about extreamly large sections of the antarctic ice shelf collapsing.

 

So it is the news reporting that is biased to repporting events in the northern hemisphere.

[Airmid]

But wait a second' date=' what about Antarctic ice? If global warming is the problem, why don't we hear anything about that? The answer is because there is no progressive trend in summer ice coverage in the Antarctic, only aimless fluctuation.[/quote']

Average temperatures worldwide are rising. (Temperature record) As to the temperatures for Antarctica, a considerable debate is going on. Probably the best conclusion is that parts of Antarctica are heating up, while other parts are cooling down.

Now' date=' ask yourself: if [i']global[/i] warming is the problem, why is the ice sheet of one pole melting while the other one stays more or less the same? Shouldn't we see symmetric effects in how the different hemispheres of earth are affected,

We would only see symmetric effects if earth would be a perfectly symmetric system. But it isn't, if only because the northern hemisphere contains much more land mass than the southern hemisphere. As a result, ocean currents, which have a major influence on local climate, are completely different in the northern and southern hemisphere. There even are climate models that predict that the northern hemisphere will cool down as a result of global warming. That said, I should also say that current climate models are far from perfect.

This is not a global problem. It is a regional problem' date=' and should be dealt with as such. Something like Kyoto will [i']not[/i] have an impact on the melting of the Arctic ice sheet.

I think you focus too much on the word problem here. In this sense, one could say that global warming isn't a problem at all, because we're not experiencing any adverse effects at the moment. But the point is that we are most probably going to feel the effects if we continue to pollute the air at the rate we are doing it now. What the effects will be, and what their magnitude will be remains unclear at the moment. But by the time we have figured this out, I don't want to run the risk we have entered a road of no return.

 

Airmid.

[bascule]

I don't know much about meteorology, but isn't the northern hemisphere somewhat isolated from the southern, as far as weather patterns are concerned?

 

Global warming research is concerned with climate forcings which are global in extent. This desperately needs to be contrasted with regional warming effects, to which far too litte attention is paid. A regional focus is needed to address these problems. "Regional warming" just doesn't have the alarmist ring to it that "global warming" has.

 

And if so, you wouldn't really expect the effects of, say, manmade emmisions in the northern hemisphere to have an equal effect in the southern, would you? At least not in the same time frame?

 

Obviously not, but that's how the media wants to paint it. They're unable to seperate effects which are global in extent (i.e. the greenhouse effect) from regional scale effects. This is a major issue in climate science reporting.

 

Global warming is melting as much ice in the south as in the north. The reason there are more news reports about the arctic ice is that more people live near the north pole.

 

That isn't true at all. Sources:

 

National Snow and Ice Data Center

 

There is no progressive trend observable in these graphs, only aimless fluctuation. To quote American Association of State Climatologists director Dr. Roger Pielke Sr (who happens to be the head of my research group):

 

Trend analyses to near the current time of Antarctic sea ice area and extent anomalies are available from The National Snow and Ice Data Center’s website . In their data, a continued increase in the areal coverage of Antarctic sea ice is evident!

 

Why is this not also reported by the media? In terms of a global warming effect, is the area reduction in the Arctic sea ice compensated by an area increase of sea ice in Antarctica?

 

The positive trend in the Antarctic, in contrast to the Arctic, raises questions about the causes of the sea ice trend. If it were a “global warming” signal (i.e., “global in extent”), we should expect similar behavior in both hemispheres. However, if warming is the reason for the reduction the area coverage of Arctic sea ice, it is a regional warming effect.

 

Also, NASA reported in 2002 that Antarctic sea ice cover is increasing

 

I do remember reading several articles about the ice shelf in antarctica melting as well. For example http://www.newscientist.com/channel/earth/dn8173 states that "The edges of the Antarctic ice sheets are slipping into the ocean at an unprecedented rate" (oct 2005).

 

According to Dr. Pielke Sr:

 

The obvious question is what is the source of their data?

 

Their conclusion about antarctic sea melting clearly conflicts with the NSIDC data http://nsidc.org/data/smmr_ssmi_ancillary/regions/total_antarctic.html#nsidc, as well as tropospheric temperature trends at the high latitudes in the southern hemisphere (see http://www.cdc.noaa.gov/cgi-bin/Timeseries/timeseries.pl?ntype=1&var=Geopotential+Height&level=500&lat1=-70&lat2=-90&lon1=-180&lon2=%2B180&iseas=0&mon1=0&mon2=0&iarea=1&typeout=2&Submit=Create+Timeseries, which show long term cooling (using the 500 hPa heights for 70S to 90S).

 

He concludes the way these studies are reported by the media are an obvious example of cherrypicking.

 

Average temperatures worldwide are rising.

 

Nobody is debating that the climate system isn't warming (if they are, they're a crackpot). However, Dr. Pielke Sr. addresses this issue as well:

 

"Global warming" requires that the climate system accumulate Joules. An average global temperature is not an effective procedure to evaluate this warming, even if we could agree on what is actually meant by a “global average temperature”. If Joules accumulate in one region, but are lost elsewhere, it is the sum that represents the heat content changes of the Earth’s climate system as I discuss in Pielke Sr., R.A., 2003: Heat storage within the Earth system. Bull. Amer. Meteor. Soc., 84, 331-335 http://blue.atmos.colostate.edu/publications/pdf/R-247.pdf.

 

As to the temperatures for Antarctica, a considerable debate is going on. Probably the best conclusion is that parts of Antarctica are heating up, while other parts are cooling down.

 

I refer you to the NCEP Reanalysis data I linked above. There's an overall cooling trend in the higher latitudes of the southern hemisphere.

[Airmid]

Back to basics: what's the point you're trying to make, bascule?

[bascule]

Looking at an article which addresses the paper's conclusions more specifically, it appears my concerns were addressed:

 

http://news.bbc.co.uk/1/hi/sci/tech/4661830.stm

 

The original article makes it sound as if the study claimed global warming is causing increased meting of Arctic sea ice. The above article makes it clear that the study was predicting that in the future, global warming could increase the rate at which Arctic sea ice was melting because increased CO₂ would compound the regional warming effect.

 

Thermal expansion of water is already believed to be raising sea levels by around 1.8cm per decade; but the extent of that rise would be considerably greater if the Earth's major ice sheets, in Greenland and Antarctica, were to melt.

 

Global warming is most certainly causing rising ocean levels through thermal expansion (and the melting of glaciers) but I've seen no substantive paper tying the melting of Arctic ice sheets to rising sea levels. Unfortunately the article mentions nothing about who authored the paper. Perhaps tomorrow I'll try to dig it up.

[Sisyphus]

Global warming research is concerned with climate forcings which are global in extent. This desperately needs to be contrasted with regional warming effects' date=' to which far too litte attention is paid. A regional focus is needed to address these problems. "Regional warming" just doesn't have the alarmist ring to it that "global warming" has.

 

Obviously not, but that's how the media wants to paint it. They're unable to seperate effects which are global in extent (i.e. the greenhouse effect) from regional scale effects. This is a major issue in climate science reporting.

[/quote']

 

But wait. This kind of seems like a straw man. I don't think anybody is claiming that the effects of global warming will be exactly the same everywhere. Obviously an overall increase in temperature would have very different effects in different regions. Is it not a regional-specific manifestation of a global problem? I mean, it's not like the Arctic Ocean is producing a lot of greenhouse gases...

[bascule]

Global climate forcings are, by definition, global in extent. If we see one trend in one hemisphere and the opposite trend in the other hemisphere, then the cause of these trends cannot be global in extent.

[Sisyphus]

Why not? The geography isn't symmetrical and neither are the sources of greenhouse gases. It seems like you're defining "global warming" in such a way that it couldn't possibly happen.

[bascule]

Please reread my previous post again.

 

If climate forcings are global in extent then we should see trends symmetrically reflected in both hemispheres.

 

According to the NCEP reanalysis data I posted there has been a progressive cooling trend in the southern hemisphere. We see a progressive warming trend in the northern hemisphere.

 

If you disagree with this assertion, can you please tell me what climate change forcing which is global in extent could be responsible for heating in the northern hemisphere but have no effect in the southern hemisphere?

 

And no, the answer is not CO₂

[Sisyphus]

I don't know whether there's global warming, and I don't know what's causing it if there is. All I'm saying is that your assertion is that an impossible situation is not happening. If "global warming" is "symmetrical climate change in both hemispheres," then "global warming" cannot ever happen, because the two hemispheres are not symmetrical. Obviously, even something which affects the entire planet is not going to affect every region in the same way. That's all I meant by "a regional-specific manifestation of a global problem." Like the same illness affecting different body parts differently.

[bascule]

All I'm really saying is that global climate change forcings do not appear to be responsible for the melting of Arctic sea ice. Take that for what you will.

[Airmid]

Time to start talking about El Nino (El Nino and La Nina and El Nino/La Nina from space).

Disclaimer: I am aware that there is little indication that El Nino and global warming are directly interrelated. But I'd still like to talk about El Nino, because it represents a mechanism to explain some aspects of what is going on.

 

In short, the phenomenon is the build up of warm (El Nino) or cold (La Nina) water in the pacific area. The phenomenon is perfectly natural, and seasonal, and usually starts at the end of each year. Why one year would produce a El Nino while another year produces a La Nina, and yet other years neither of them, is unknown. But when it happens, it has a profound effect on climate worldwide. The reason for this is that it disrupts ocean and air currents.

 

I'm bringing up the subject in this conversation for a number of reasons:

First, to show that climate is a very complicated and interrrelated system. We have no idea why El Nino/La Nina occurs. But when it occurs, El Nino shows us that regional changes can have global effects, and that those effects are not uniform. This is why I find it so hard to understand why you are talking about "a regional problem".

 

Second, as an illustration of the distribution of heat around the globe. If the EL Nino information makes anything clear, it is that heat is not distributed evenly. If I was to make a simple model of earth climate, I would use the simile of a heat exchange engine, like a simple fridge. In this simple fridge, you'd have a circulation of cooling fluid, which absorbs heat from the inside of the fridge and releases the heat again to the outside. In my simple climate model, air currents and ocean currents behave in much the same way.

There is a connection with global warming there. If I increase the input of energy in my simple fridge, the inside will become cooler and the outside warmer. The change in temperature outside the fridge will be larger than the change inside, though, because some of the extra input of energy will be released as heat: the average temperature in my system is going up. So, my simple fridge model will explain possible heating up of the northern hemisphere and at the same time cooling down of the southern hemisphere as the result of global warming. Of course my model is far too simple, but it serves as a way to be not surprised when this is the case.

 

Third reason to bring up El Nino is that it causes fluctuations also in the climate of Antarctica. Because of that, I find it very hard to discuss whether Antarctica is heating up or cooling down. In the ideal case, we would need a model that calculates what the normal temperature of Antarctica should be, considering El Nino and other natural fluctuations. Only by comparing results from such a model with what we measure, can we make make out whether Antarctica has abnormal temperatures. I can't make out whether the graphs you presented us with make use of such a model.

 

All considered it's very hard to prove that global warming actually is happening, let alone what its effects would be. I couldn't agree more with Dr. Pielke, when he says that the total energy budget of earth should be considered. Tough job, but I think that's the only thing that will convince the unwilling Kyoto partners.

 

Airmid.

[john5746]

http://www.mri-jma.go.jp/Dep/cl/cl4/cl4.html

 

Some simulations

[gcol]

WARNING: This is satire....( I think).

 

Do some people really think that what happens in one hemisphere does not affect the other?

 

North warmer, south colder: Great trade opportunity here, export the excess down south, who cares about the penguins. If there is a temporary imbalance, the winds of change will stir things around and even it up.

 

Global warming is a myth? Go join the flat earthists.

 

The mechanism of global climate change is complex: cloud cover and dust, temperature down. carbon dioxide/methane, up. Depletion of the ozone layer, er.. pass. But it does, statistically, appear to be happening. Lets all sit around fiddling while Rome burns. A couple of mega volcanoes, a touch of axial tilt, seasoned with a hint of nuclear winter, and there will be something really meaty to theorise about.

 

"Seen from the moon, the earth looks very pretty and rather small. I wonder how long it will stay that way?"

[Prime-Evil]

My superficial guess is that carbon dioxide will distribute itself quite uniformly even if it is overproduced in the Northern Hemishere. Positive feedbacks like land use and snow and ice cover will vary North and South, but current carbon dioxide levels should indicate that climate change is a global problem, even if global warming advances more quickly in the Northern Hemisphere.

 

It raises an interesting question though. What might happen to critical equatorial regions like the Saharah and Indian Ocean if there is a change in the temperature gradient between Africa and Eurasia? Also ocean currents in the Pacific.