Tuesday, November 06, 2012

My Interview with a VERY Well Known Climate Scientist - Q and A

Another post on climate change...

Oh Lord! Here we go!  Bells are going off in your head. I can hear it.

You've already made up your mind on what this is about.  Your opinion is made. The conversation is now off of the rails with no hope of resuscitation. End of discussion.  Your done...

Please, allow me to finish.

A few months ago after reading some climate articles posted on Twitter, I tracked down the author--a well known climate scientist--on Facebook. I had read many of this individuals posts before and wanted to ask the scientist a few follow up questions.

Before I show our question and answer exchange, Remember several things about me.  1) I hate politics.  2) I love science and weather and 3) I strive to better understand the cognitive biases that govern my thinking.  In a nutshell, no politics here; all science (I do have my own personal scientific views on this subject). Yet my goal of this exercise is to present the science as objectively as possible with compelling scientific arguments filtered through a lens that washes out my own potential cognitive biases so as to promote a civilized scientific discussion. A tall order for anyone to do. Humility is tough to chew.

In an attempt to diminish any preconceived notions you might have. the scientist's identity will stay concealed. I will refer to this scientist as "Pat". Laugh if you must.


Question 1:

When we look at the length of the droughts of the 1930s, they were much longer and more severe according to the PDSI (Palmer Drought Severity Index) data. Once again playing devils advocate, why is this year's drought different? 

Hi Scott--as I understand it, we set all time records for the % of the country (>60%) in drought this past month. By several metrics, this summer's drought exceeded what has been seen for any other single year. The issue of persistence of drought (i.e. how many years in a row a given state is in drought) is something else, that takes several years to evaluate. While the drought of the 1930s already likely had an anthropogenic component (soils were warmer, and evaporation was greater, than it would have been prior to anthropogenic warming), this year's drought likely had a much greater anthropogenic component, as many regions broke all-time temperatures that were set in the Dust Bowl years.

Question 2:

Is there a way to determine whether or not the NAO (North Atlantic Oscillation), AO (Arctic Oscillation), ENSO (El Nino or La Nina), etc plays more of a part in a specific weather episode (extreme warmth, etc) than AGW? Can the models do this considering that the NAO, for example, is more random in its behavior than say ENSO? Doesn't the PDO and AMO have impacts as well or are they mitigated due to the AGW (Anthropogenic Global Warming) signature?

Well the problem is that anthropogenic climate change may have a projection onto each of these modes, so the separation isn't clean. However, this is where the science gets considerably more uncertain, not the least of which because signal-to-noise ratios are quite a bit lower (the internal variability noise is very large). However, its probably fair to consider the distribution of weather regimes as basically stationary. i.e. we had large positive AO/NAO excursions, etc. in the past, and there is nothing clearly extraordinary about the atmospheric circulation patterns we are seeing, the only thing that appears extraordinary is both the scale and magnitude of the warmth. But I don't don't that we'll see a fair bit of attention paid to these questions over the next few months and climate scientists perform a scientific 'autopsy' on the anomalous 2012 North American summer warmth...

Question 2B:

Thank you so much. Would it be a safe assumption to say that the +++AO/NAO last winter was more a random fluctation? Is the behavior of the AO linked to arctic ice lose/gain?

Scott--that is a great question, to which I wish I knew the answer. There are theoretical arguments that have been made for a tendency for both a more positive AO/NAO and a more negative AO/NAO. The sea ice impacts are more speculative and
not currently well represented in the models, and so its hard to put too much confidence in the model projections w.r.t. this issue. But the absence of evidence is not the evidence of absence, and if I were a betting man, I would suspect that sea ice melt did play
a role in the anomalous AO/NAO state last winter and *could* be a harbinger of what is to come...

Question 3:

One other question (there is always another :) Doesn't the negative PDO and the warm pool in the central Pacific drive the western trough and thus the continental ridge creating an upper level environment that is more conducive for sustained heat/Texas drought in 2011? I believe you addresses this last week in another response but is the AGW signal embedded within the overall upper level pattern? Finally, does an increase in CO2 in the oceans alter the PDO, AMO cycles. Is seems as if they are fairly consistent...Sorry, that was 3 questions :) Thanks, Scott

Scott-no question the anomalous atmospheric circulation, which in part is set up by large-scale SST patterns ("PDO" is a bit of a pet peeve--itis just an imperfect characterization of changing North Pacific SST patterns that contain both anthropogenic and natural variability contributions) has something to do with the North American drought. But without dispute, the drought has been worsened by record-breaking heat, that leads to greater loss of moisture from soil via evaporation and evapotranspiration.

Question 4:

Concerning the AMO, I have read some draw a causal relationship between the +AMO (Atlantic Multidecadal Oscillation) and arctic ice cap growth/melting. Could the +AMO cause or enhance the rate of melting? Thanks Scott

Hey Scott. In the study discussed by Appell in the link, the AMO (a coin I actually termed--as I discuss in my book) is estimated as being responsible for at most 30% of observed melt. My guess is that its less than that--30% is just an upper-bound estimate.

Question 5:

In order for AGW to directly cause the heat waves like current one in the US, would the increase in temp need to be caused by an increasingly stronger continental ridge cause by a change in the wave pattern around the globe? In other words, is AGW causing the wave pattern to change? Is this a correct supposition?

Scott--fair question. But no, you can't explain the record-breaking warmth by atmospheric circulation alone. We've had very similar circulation anomalies in mid-summer in the past, and they didn't lead to the same level of warmth. So while anomalous circulation (i.e. an unusually pronounced ridge) is certainly contributing to the pattern of unusual warmth it is not, alone, an adequate explanation for record-breaking heat. That's the key point here...

Thanks for answering my comment. Much appreciated.

Question 6:

How does a temp increase on the global scale cause spot increases in the regional areas (i.e. Central US)? Are there other intermediate steps that have to occur in the atmosphere (cause and effect) in order for these heat waves to happen? How can I use atmospheric physics to describe what is happening (AGW = regional heat waves) Thanks for your time!

Sure thing Scott, happy to do so. In short, the warming is not uniform in space or time, there is much variability and much noise. In any given year, ENSO, the NAO, and other factors will make certain places warmer than they otherwise would have been, and other places colder. But over time nearly everyplace warms up, and the pattern of warming from greenhouse gases isn't uniform. You get more warming over continental interiors and more warming in the Arctic owing to ice-related feedback mechanisms (both are actually evident in the pattern we've seen this year).

There is a great animation based on the NCAR CCM climate model projections that shows all of this very nicely (sorry its about 37 MB): 


Question 7:

How much CO2 is absorbed into the oceans?

Thus far about 30% of CO2 appears to have been taken up by the ocean, and about 15% by the terrestrial biosphere, so that the "airborn" fraction, i.e. the CO2 that is remaining in the atmosphere is about half of what we've emitted. One of the worries is that these carbon "sinks" become saturated and the CO2 begins to build up even faster.

Question 7A:

Does an increase in CO2 in the oceans change the thermocline circulation over time? Thanks again...Scott

I don't know of any direct influence on the CO2 itself, per se, on the thermohaline circulation, but the *warming* is predicted to influence the circulation (e.g. through the freshening of the upper ocean due to high-latitude melting ice).

Question 7B:
Are these carbon sinks re-radiated back into the atmosphere or do they stay in the ocean? If so, at what rate?  

The carbon sinks can eventually lose their ability to take up carbon, in which case they might even become sources--and in that sense, yes they can actually even lose some of the previously stored carbon to the atmosphere. there is one of the concerns, for example, of the melting of the permafrost and potential release of methane that had been stored there for many thousands of years.

 Question 7C:

Why are surface temps used to measure global temps and not satellite UAH numbers?

Both are used, but satellite temps are an integrated measure of lower atmosphere not surface. And unfortunately, UAH record has been compromised by so many errors over the years (sign error and algebraic error that led to an incorrect conclusion regarding the *sign* of the warming trend---I discuss this in my book) that nobody uses it. There are other estimates (e.g. RSS) based on same satellite data (now that UAH finally released a few years ago), and these reaffirm the surface record indicating that surface and lower atmosphere both warming. The instrumental record is of course much longer, and hence more useful for assessing long-term trends...

Monday, November 05, 2012

Sick of Politics? Need To Vent? This is the Place To Do It!

Earlier today, I placed a moratorium on political opinions on my Facebook Fanpage. I directed people to comment only objectively about facts, data and, if they chose, the psychology of political ads. Here was my initial post:

"I'm venting here. Why is it that when anyone writes the name of a candidate for President on a post IN ANY CONTEXT, people think that the post is designed to elicit a political response. I realize that we are 24 hours from Election Day and we are all fired up about what we believe. Frankly, you're political beliefs are your own. I personally deal in analysis, data and try to remove myself from the politics. Remember, we all have cognitive biases which unfortunately surface with an accelerated vigor during an election year that make us react impulsively to words like "Obama" and "Romney". So if I write an update tomorrow that shows the Electoral College count, note that it is not an endorsement of a candidate but a look at the numbers. Nothing more. Nothing less. Sigh. Time for a snack."
I continued sometime later with this...
I like to analyze the psychology of campaign ads. They only give you the pieces of information that are just enough to validate their claim on a specific topic and, at the same time, that information is pushed into your psyche at that fundamental level which forces your cognitive bias to win over your rational, objective side. These ads cater to your political leanings by weighting the argument to fit your preconceived notions therefore cementing your decision through repetition on tv. This happens over time. They focus on words like: China, Taxes, Government, Stimulus, Corporations, Middle Class, Wealthy, The Rich, etc. I bet if we looked up political ads from 30 years ago, they probably aren't much different.
After a hour or two, several people started to go down the "comment road" that I frowned upon earlier. Namely, the road which is riddled with political opinions.
JOHN:  I don't endorse anyone, go Romney. Just saying
then Mary said
MARY: "lol ok if John can endorse Romney.. I'm just saying.. lets go with the right choice.. Obama.... 4 more years..... lets give him time to finish what he started... forward... not backward..."
So I responded with....
John and Mary, here we go. This is how comment threats deteriorate. I can feel this going down a road a political road that can only lead to negativity. See my blog post on comment threads http://sabolscience.blogspot.com/2012/09/the-evolution-and-devolution-of.html
Then it hit me I'm going about this all wrong. On the eve of the election, people are at their wit's end. We are sick and tired of the same old commercials. We are sick of the coverage. We are so sick and tired that most have become apathetic. Our everyday existence has been plowed over with political rhetoric. We are an overly stimulated society The general populous has become recalcitrant. We simply don't care anymore and we want this display of one-upsmanship to end. Our torpid minds need a bleeder valve. Something to take the pressure off of the relentless pounding we've taken for 18+ months. My Facebook Fanpage is that bleeder value. Head on over to it and voice your displeasure, your political opinions, your disdain, your frustration, your dislike for the weather, your apathy for the Browns...as long as its clean. This offer will only be extended until midnight tonight.

So have at it. Let the catharsis begin.