1) the planet is warmer…
Fair Summary.

2) the data for ancient temperatures…
Some of it is, but some of it is based on tree ring data that is quite controversial. I would reference you to climateaudit.org where you can have a look at a critical look at the Mann et al work.

3) temperature data from more recent history…
It is very difficult to reconcile this data. Past (and present) data is adjusted and no one can say for sure that it has been done properly.. It is even more difficult to reconcile this data with paleo data. Climate operates on a millennial time scale and we have a 10% or less sample of an unknown chunk of a single cycle that is of dubious quality.

4) There seems to be consensus that a “long term” (since the little ice age) heating trend has accelerated over the time…
I would take issue with that statement. Temperature rise has been pretty constant.

Anecdotal evidence …
Anecdotal evidence is exactly that and has little place in science. Moreover, the specific examples you site are unlikely to be related to atmospheric temperatures. Also, the data we have is on such a short time scale that it is pretty meaningless at this point. Glaciers have been thinning since the end of the ice age. The northwest passage has been navigated before. No one knows how often ice shelves collapse or for that matter the long term mechanism that causes it.
It is clearly warmer. As per your #1 above.

5) Ice core data …
It might be important to point out that ice core data has very low resolution. I.e., it cannot say much about a specific year or even decade. Climate operates at the century and millennial time scale.

6) Carbon dioxide levels are trending higher. It is relatively easy to estimate the amount of “carbon” that has been reased from underground “storage” though fossil fuel use.

This might be an excellent exercise. Estimate the annual contribution of man-made CO2 to the atmosphere and compare that to natural oceanic outgassing and/or a Mt St. Helens event. In addition, talk obout equilibrium. See my comments below about Henry’s law. I.e., what happens to the carbon once it is released. What is the carbon cycle?

7) In addition to the fact that use of fossil fuel seems to coincide with increased CO2 levels. Radiological anaysis of oxygen isotopes found in CO2 suggest that the added carbon dioxide is of paleo- origin. So the increase in CO2 can be termed anthropogenic

CO2 does not necessarily coincide with fossil fuel use. It has been much higher in the past. Paleo-origin is not a slam dunk for man-made. Natural outgassing from the oceans could well be paleo – especially if it is from methane-hydrates.

This might be a good segue to talk about Henry’s law and equilibrium. Perhaps it is even possible for your students to estimate the Henry’s law constant for CO2 and seawater over a small change in concentration and temperature (it will be approximately constant for a small delta).

8) The idea that carbon dioxide traps heat…
That is pretty much undisputed. What is disputed is the relative sensitivity for a doubling of CO2. Also controversial is the direction and magnitude of any feedback mechanisms.

9) Tempertures on earth have fluctuated wildly…
Good enough

10 ) So to my mind the debate surounding climate change is one whcih centers on the issues of human causality vs pure coincidence

I think: Human causality, extent, beneficial or not? Also, it is not climate change. It is the proposition that Man’s use of fossile fuels is catastrophically warming the planet. What are the scientific principles that must be met for a proposition to be elevated to a theory?

1) It seems that a one yr (month jan) jog in a 100 yr trend line up or down is hardly a basis for confirmation or refutiation of a hypothesis. Why the big deal over a single datum?

For me, it is the lack of transparency in the manner that the data is collected and adjusted. Some of the adjustments seem to fly in the face of reason for example, a measurement in 2008 affecting the adjustment of data from decades prior.

But I agree. A single data point is just weather. If you are a regular at WUWT you know that Anthony has done a great deal of work regarding the quality of the surface station measurements. It is interesting to see how individual data points stack up for stations vs satellite. I believe that that does give some insight into the quality of the data gathering and adjustments.

2) To my eye it does not appear that a one hundred year increase was earased in one season. It also seems that a single data point would have to be well outside the extremes of the data set to signifcantly alter a running mean. Wouldn’t the temperature trend in a more thermally stable medium such as the oceans be more valid and aren’t these temperatures increasing?

No. The oceans appear to be cooling at least in the short term. The 100 years of warming you speak of did not happen in a straight line. PDO cycles are roughly 60 years in duration, 30 warming and 30 cooling. I believe that much of the data watching is because some believe that we have flipped to another 30 year cooling trend. But the bottom line is that no one knows much at all about the oceans.

3) Solar activity is advanced as an alternate expalnation for a warming trend and with the occurance of the onset to the next solar cycle “delayed” there seems to be a rush to atribute the falttening of temperature rise to solar activity. I seem to recall that the correlation between solar cycle and temperature fluctuation was relatively weak?

The solar correlation IIRC is at least an order of magnitude better than the CO2 correlation. But correlation does not prove causality. The climate is a chaotic system that is in constant adjustment to a multitude of factors, many of which I am sure we are still ignorant about. No one can say what factors are changing, how fast and by how much. No one knows what the hysteresis of the climate is. I.e., if you could hold everything constant and let the climate come to equilibrium and then make a step change how long will it take the planet to reach a new equilibrium.

I think it is a mistake to look for a “Cause” man-made or otherwise. Climate is the sum of an incredibly complex system that is not well understood at all.

4) Malkinovich cycles are also offered as a possible explanation. Again isn’t the correlation fairly weak or at least the currnet positions of the earth don’t fit the argument?
Dunno. Have to pass on that one.

5) ice core data, offered by http://www.grida.no/climate/vidal, shows a strong correlation bewteen repeated cycles connecting CO2 and temp over a 400,000 year period ( I can’t post the graphic) . Why wouldn’t we assign this kind of data a great deal of significance inteh debate over causality

Your link did not work for me. Ice core data clearly shows that CO2 trails temperature change. This is pretty much undisputed. .

6) isn’t weather generally viewed as short term variations and climate regarded as the longer term trend in temperature and moisture distribution.? Again why a knee jerk either way to a recent temperature event when the event seems to be a change in the weather not a change in the climate.

It depends on what you mean by short term. IMO anything less than a millennial is short term when it comes to climate. Even that can be considered short term. For example you could speak of the climate during the period entering a great ice age, the climate at the heart of a great ice age or the climate during an interglacial period. Climate is not static.

A more debatable subject would be the future extent of warming due to the cause. And even more open to debate is the effects of that warming, and the magnitude of those effects.

As time passes, and data is amassed, the above debates will settle down; as the future trend of warming becomes the past record and as some effects materialize and some don’t, the list of possible paths will become populated with materializing real ones. Over time, perhaps four or six decades, the real picture will emerge, and it will not be exactly any of the pictures painted by proponents and opponents of today, but a blend of them; perhaps worse than any, perhaps better than most.

If it is better than most, the people of 2080 or 2100 will read of today’s debate and shake their heads and smile and wonder about the ignorant people of 2010. If it is worse than any, the people of 2080 or 2100 will read of today’s debate and shake their heads and cry and curse the ignorance of the people of 2010.

They may ask why that, in 2010, inaction was chosen when action could have not only averted a catastrophe, but formed a base of an incredible technological revolution which replaced the inefficient IC engine and the pollution of fossil fuels with clean energy, reinvigorating the American, and global workforces, not only creating a global economic boom but, as a side benefit, insuring against the possibility that global climate change as caused by human activity would not happen? We of 2010 will not answer; we will be dust. Some say when we die we will be held accountable for both our actions and inactions. Believe that or don’t, the logic and the ethic of positive action seems unassailable.

http://www.huffingtonpost.com/joseph-romm/the-great-ice-age-of-2008_b_96409.html

I am skeptical but it is worth looking at.

GISS reports a increase for Feb and March of +0.26°C +0.67°C respectively.

Worth our consideration for sure.

http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts+dSST.txt

Hello

I’m an Advanced Placement Environmental Science Teacher in a suburban High School.

My first goal as a teacher is to make kids think, the second is not to give out any bad information as fact. Envi Sci runs the gammot of Science/political hot buttons from creation v evolution to climate change.

I am interested in opinions on the recent drop in temperature and the comments here seem to be focused enough to hope for some useful replies.

i intend to present the current theory/hypothesis as it is held by the “majority” and then present the dissention as best I can research it.

there seem to be some of each here on this forum. I do hope to share yoru thoughts with my students. Given some of the comments/suggestions mae by some angery contirbutors I will not be sending my studnets directly to the this forum ( I hate hostile parents) but I do hoep to use you as resources if you are willing. ( aka if you reply)

If I can summarize what I have as the base line data I’d appreicate some feed back.

1) the planet is warmer than it was at the end of the last ice age 15 – 20 thousand years ago. ( younger dryas) The planet is colder than it was a few thousand years ago during the medievel warm period and it is currently warmer than it was a few hundred years ago ( we’re coming out of the “little ice age)

2) the data for ancient temperatures is based on ice core analysis and geologic date including sealevel changes, fossilized palnt and animal records adn so forth. The methods reflect credible scientifc work and principles.

3) temperture data from more recent history is based on human record keeping with limited technology. While the most recent temp data is collected by ground based and satelite information ( high tech information)

4) There seems to be consensus that a “long term” (since the little ice age) heating trend has accelerated over the time period that corresponds to the industiral revolution ( last 100 yrs +/-). Anecdotal evidence such as retreating galciers, thining ice caps, collapsing ice shelves and open expanses of arctic ocean and a navigable northwest passage suggest that the climate is warmer now than it was hundreds of years ago

5) Ice core data also provides data on the composition of the atmosphere specifically Carbon Dioxide. Like the temp data I mentioned the method/techniques behind the data seems to be regarded as sound science.

6) Carbon dioxide levels are trending higher. It is relatively easy to estimate the amount of “carbon” that has been reased from underground “storage” though fossil fuel use.

7) In addition to the fact that use of fossil fuel seems to coincide with increased CO2 levels. Radiological anaysis of oxygen isotopes found in CO2 suggest that the added carbon dioxide is of paleo- origin. So the increase in CO2 can be termed anthropogenic

8) The idea that carbon dioxide traps heat within the atmosphere is an accepted phenomona. without a greenhouse effect earth’s climate would be substantially different.

9) Tempertures on earth have fluctuated wildly in the past, and compared to truly ancient climates the past two hundred year temperture profile is nearly flat

10 ) So to my mind the debate surounding climate change is one whcih centers on the issues of human causality vs pure coincidence

Here are some questions I am trying to form opinons on, and I want my students to form opinons about as well.

1) It seems that a one yr (month jan) jog in a 100 yr trend line up or down is hardly a basis for confirmation or refutiation of a hypothesis. Why the big deal over a single datum?

2) To my eye it does not appear that a one hundred year increase was earased in one season. It also seems that a single data point would have to be well outside the extremes of the data set to signifcantly alter a running mean. Wouldn’t the temperature trend in a more thermally stable medium such as the oceans be more valid and aren’t these temperatures increasing?

3) Solar activity is advanced as an alternate expalnation for a warming trend and with the occurance of the onset to the next solar cycle “delayed” there seems to be a rush to atribute the falttening of temperature rise to solar activity. I seem to recall that the correlation between solar cycle and temperature fluctuation was relatively weak?

4) Malkinovich cycles are also offered as a possible explanation. Again isn’t the correlation fairly weak or at least the currnet positions of the earth don’t fit the argument?

5) ice core data, offered by http://www.grida.no/climate/vidal, shows a strong correlation bewteen repeated cycles connecting CO2 and temp over a 400,000 year period ( I can’t post the graphic) . Why wouldn’t we assign this kind of data a great deal of significance inteh debate over causality.

6) isn’t weather generally viewed as short term variations and climate regarded as the longer term trend in temperature and moisture distribution.? Again why a knee jerk either way to a recent temperature event when the event seems to be a change in the weather not a change in the climate.

Sorry if the questions are too “elementary”. I hope you won’t scoff at my lack of facility in the dicer details. Before you fire back please be restrained if I’ve offened you I will share your ( editied) thoughts with 50 17 year old future citizens. fIf you care to share your credentials I do suggest my students consider the source) So make your best arguments for them not for me….

thanks

Nclark

( please forgive typos, i can spell but typing is a bother and this has already used up significant grading time) Off to the exams

http://mitgcm.org/pelican/online_documents

I gather from their discussion it is about as good as documentation gets along these lines but I cannot verify.

Having looked into their heuristics for nearly a year, I concur:

“If I’m at all understanding the general idea of what the GCM’s are doing, it would seem that they use simpler models of known physics and sprinkle in variables which ought to supply forcings and such, and then plot the trendline and call it a day.”

Really? A citation would be nice. There was an event thousands of years ago when a huge ice dam burst letting a reserve of fresh water, for which there exist no analog today, flowed into the ocean in a matter of days or weeks. This did affect the Gulf Stream salinity, probably. I would be interested in hard science which lists this as a possibility today, as opposed to speculation in the popular press or in Hollywood movies.

Also, the cold in the north would be balanced by warm to the south, as heat would be trapped in the tropics.

Sunspot cycles way foolishly overated, but has an effect but not enough to show up unless dramatice like a Dalton, Maunder or milankovitch.

it’s La Nina, increased baroclincity for current storm track etc.

http://data.giss.nasa.gov/gistemp/graphs/Fig.E.lrg.gif see La nina bottom blue and have fun