John Christy is an atmospheric scientist and Professor of same at the University of Alabama in Huntsville, and winner of achievement awards from NASA and the American Meteorological Society. He was a lead author of the IPCC's 2001 Assessment Report, but in 2007 was quoted in the Wall Street Journal as saying, "I'm sure the majority (but not all) of my IPCC colleagues cringe when I say this, but I see neither the developing catastrophe nor the smoking gun proving that human activity is to blame for most of the warming we see."
The awards he received were for his work in helping develop a temperature dataset based on satellite measurements, and one of the major datasets used in climate science is just known as UAH. He is commonly perceived as a skeptic, but as has been the case with every interview I've done in this sector, the truth is far more nuanced. Professor Christy was kind enough to respond to my request for an interview very quickly, so without further ado...
Examiner: You are commonly labeled as a 'skeptical' scientist who does not agree with the IPCC consensus regarding human contributions to climate change. How accurate is that, and how would you describe your own beliefs regarding this?
J.C. I am mainly skeptical about those who claim to be so confident in understanding the climate system that they know what it is going to do in the next 100 years. This is my main complaint - overconfidence. We of all professions should be the most humble because there is so much about the climate system that we simply do not know. See my testimony given to the Inter Academy Council in June concerning these ideas - I think you will appreciate it.
(In his June testimony to the Inter Academy Council, Christy testifed that he felt the IPCC's overconfidence in climate models was not justified. He also said: "The first objection I raised regarding the Third Assessment was that the fabled Hockey Stick was oversold as an indicator of past climate change. This was well before the critical work of the Wegman Report, National Academy of Sciences, McIntyre’s papers and the East Anglia emails. Indeed, I urge you in the strongest terms to engage Stephen McIntyre in your deliberations at a high level as he has accurately documented specific failures in the IPCC process, some of which I can attest to, as I was there.")
Examiner: What unresolved issue or issues should the scientific community be focussing its gaze on with regards to climate change in 2010? Atmospheric sensitivity to a doubling of CO2?
J.C. Evidence is building that the sensitivity is less than models assume.
Examiner: The role of the oceans in exchange of CO2 and heat?
J.C. This relates to sensitivity.
Examiner: The role of the clouds?
J.C. This is directly related to sensitivity, i.e. how do the reflective clouds respond to an impulse of warming - evidence indicates they expand (reflecting more sunlight) and counteract the warming. This has also been shown for cooling events, i.e. that clouds contract when a global cool spell occurs to let in more sun and warm the planet.
Examiner: The accuracy of the historical records?
J.C. This is an ongoing effort - to build an archive of raw observations in which all parties have confidence.
Examiner: What are you personally focussing on in your work?
J.C. Measurements of all types. I just recently had a paper on snowfall in the southern Sierra published showing no trend in the last 94 years which indicates natural water resources in the San Joaquin Valley are fine, so that shortages are clearly a function of management and law (see attached). I am still building temperature datasets of the surface and upper air to document the response (temperature is a good response variable to forcing) of the atmosphere to forcings of all types.
Examiner: What are your beliefs about what is happening to the Earth's climate?
J.C. Natural variability is still the major driver of the climate changes that create challenges for society. The one confident conclusion we can make about added CO2 is that the biosphere has clearly been invigorated - plants love what we do with carbon-based energy because its by-product is CO2 - plant food. (I can hear the shrieks of horror all the way here in Alabama from California, my home state.)
Examiner: What do you think governments and their citizens should be doing to protect our environment and our future?
J.C. In my experience, the wealthier the country is, the better is its environment (mainly because energy in wealthy societies is produced in high density processes like power plants rather than gathering of wood and biomass which destroys habitats.) Policies that allow human wealth and security to be enhanced are policies that can sell. The wealthier a society is, the greater emphasis it can put on protecting natural habitats, cleaning the air and water, and protecting its citizens from threats of all kinds (i.e. disease, weather disasters, etc.) This wealth building occurs best in democratically accountable societies which establish human rights for all citizens, including women and children.
Examiner: Paul Krugman recently took up a current argument that in the face of uncertainty our actions should be more vigorous, not less. How would you respond to this?
J.C. Will these actions advocated by Krugman cause economic decline, lower standard of living, etc? If so, they don't have a chance in a democratically accountable society. I think we are creating more certainty about the idea that the climate is less sensitive to CO2 than promoted in the past 2 decades. We are not all going to die on a roasting planet. The real challenge today is to prepare for the unquestionable continued rise in energy demand. Energy makes life much, much better in countless ways, so it's demand will only increase, especially in poorer countries. At some point, even carbon-based energy won't meet the demand, so new and voluminous sources of energy are needed ... and the sooner the better.
Examiner: Stephen Schneider recently co-authored a paper published in PNAS exploring the level of expertise found in scientists who support the consensus position on climate change compared to those who do not agree with the consensus. What is your reaction to this paper?
J.C. I was one of only three scientists who made both the "good guy" and the "bad guy" lists. Quite an honor I suppose. However, I think the study was pathetic. It basically says, "Those of us who agree with each other like to cite the work of our friends and not the other guys." Duh. (One of my fellow scientists calls this "tribalism" - an appropriately primitive description.) I think the more sinister motive was evident in that the paper chided the media, such at the SF Chronicle, to stop investigative-reporting and just "trust us" (the guys on the "good guys" list) when it comes to climate change. It really was an attempt to make a blacklist. In that sense, I guess I ended up being gray, which fits my hair color now.
Examiner: The IPCC accepts the submission of general circulation models from all participating countries. I think there are 23 or 24 of them right now. Is that a useful number of models to analyze?
J.C. What you want is a set of models that at least represent the real atmosphere (which none of these do faithfully relative to tests we've performed.) This does seem like a high (and expensive) number.
Examiner: Does an average derived from an ensemble of models tell us anything useful? If so, what? If not, what are the defects of looking at an ensemble of models.
J.C. Probably not. Cloud processes and responses are particularly off the mark (or at least widely varying). The question here addresses a fault with consensus - over time, individuals tend to drift toward consensus (a human foible) whether it is right or wrong. Many of the parameterizations in the models are very similar and could be very wrong, so agreement with each other is often a dangerous result as it confirms one's prejudices and gives one a false sense of success. I deal in the world of observations - i.e. what does the real world show. What we find is that models have a long way to go, which is a little ironic because they modelers have a legitimate reason to clamor for more funding to improve their poorly-performing models.
Examiner: Human emissions of CO2 declined 2.6% in 2009, although concentrations didn't change. How hopeful are you that our actions can reduce emissions further?
J.C. It is very clear that economic decline means less energy is used, and people are poorer as a result. So, one should congratulate those who created the recent economic collapse for the "good" news on emissions. However, I don't see economic decline as a long-term strategy for society to follow. The most useful option to slow the decline in emissions is to proceed on a massive construction initiative in nuclear power (which has other defensible reasons to back it up - not just alleged climate change.) In this way, gigawatts of power can be produced with little emissions. Alternatives (wind, solar, animal methane) will be just an expensive and unreliable blip on the world-wide scale of emissions growth.
Examiner: What is your best guess or opinion on what will happen to the Earth's climate over the coming decades?
J.C. The climate will throw some surprises at us and the interannual variations that we've always had will continue to cause the greatest developmental challenges. As I said 22 years ago my general rule of climate is: "If it happened before, it will happen again ... and probably worse." Are we prepared for the variations we have already experienced (i.e. 1930's, 1950's droughts, 1993 floods, any hurricane, freeze of 2007, snow of 2009-10, etc.?"). If we are prepared for those, anything induced by humans on top of the climate system's large natural variability will be manageable in my view.
Note to readers: I may go back to Professor Christy with a second round of questions. If you have your own, leave them in the comments.
Comments
Measure twice, cut once.
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Wonderful interview with a very articulate and balanced scientist. I would like to ask two questions.
1) What do you think is the solar activity contribution to our climate(considering recent papers by Scarfetta and by Lockwood)and what do you see as possible mechanisms if solar is a factor?
2) What additional areas of climate research should scientists be looking at (other than models, sensitivity and developement of reliable temperature databases) to more completely understand the primary and secondary determinants of our climate and ultimately,the drivers of ice ages?
Your colleague Dr. Roy Spencer has stated that weather makes the Earth habitably cool. The greenhouse effect in the absence of weather would drive surface temperatures to 140 F. Weather processes cool the surface to 59 F. Does this observation support a low climate sensitivity to changes in forcings such as CO2, and the existence of substantial, natural negative feedback mechanisms?
I would like get Dr. Christy thoughts on his own personal confidence levels in the ground temperature datasets (extant), including all the corrections made to them by HAD/CRU and NASA (corrected, adjusted, homogenized, "value added", etc.,), given the wide divergence over the past decade between these data and his satellite data sets. Is this controversial, or this a case of apples versus oranges?
Tom sez: "Human emissions of CO2 declined 2.6% in 2009, although concentrations didn't change."
Uh, Tom, the concentrations went UP. One of the largest annual rises ever. Which is just what we would expect if emissions declined 2.6%. You seem to have a mental block regarding concentrations and emissions.
Eminently sensible.
Basically, we have no reliable hard data (i.e. no scientifically useful data) on the past climate, models which do not accurately model real processes and no clue about the natural variability of the climate and how it affects the climate today.
As before, I second the notion that wealthier societies have cleaner environments. Wealthier societies are better able to cope with floods, plagues, earthquakes, hurricanes and any of the other myriad natural disasters that affect us.
Tom,
Thanks for getting time with JC and Dr Cristy thank you for taking the time to share insights from your important work.
Predictions of dangerous heating from man-made CO2 have so far proved overstated. Credible predictions based on observations of historic climatic patterns project that world climate is entering a cooling phase. If so, what will be the eventual impact on climate science, since the majority scientific consensus posits steady climatic heating leading to world-wide catastrophe?
Apoplectic says- "Uh, Tom, the concentrations went UP. One of the largest annual rises ever. Which is just what we would expect if emissions declined 2.6%."
Hmmm... If emissions decline but atmospheric concentrations go up a record amount, the conclusion is that atmospheric CO2 concentration depends on factors other than anthro CO2 emissions. Like oceanic processes.
Just what the alarmists would not expect.
While John Christy is a very intelligent scientist, it appears that physics is not his strong suite. The Issue of "greenhouse gas effect" is a question of physics- does the "Mann-back forcing exist? More and More physicists are publishing papers that prove that the ghg effect does not exist. The most recent is the work of Dr. Charles R. Anderson Ph.D physics. His paper can be found on his web-site An Objectivist Individualist On Some Flaws in Greenhouse Gas Global Warming.mht A small portion is included here:On Some Flaws in Greenhouse Gas Global Warming
I have just finished reading an excellent article by Alan Siddons called The Hidden Flaw in Greenhouse Theory on American Thinker from way back on 25 February 2010. The article is a little slow in developing, but finishes with a death blow to the usual theory put forth by catastrophic anthropogenic global warming advocates. I intend to explain more concisely what Siddons explained and to add comments of my own in this post *******
I have two questions for Dr. Christy. The first is regarding the official keepers of the temperature data sets and advocacy. Dr. Christy and Dr. Spencer are both skeptical of the IPCC and its overblown conclusions and they are keepers of the UAH data sets and I think have some responsibilities on the RSS sets as well. On the surface temperature side, you have Phil Jones and James Hansen. I see the the data sets as the score in the climate wars. Is it heathy to have advocates responsible for them? The second questions is related to the quiet sun. A couple of years ago the solar wind dropped to the lowest level ever measured and height of the atmosphere was found to be greatly reduced. Does this led to higher pressure over the poles and more cold air driven down to mid lattitudes like we had last winter?
Thanks Dr. Christy for some commonsense comments.
Anthony Watts has made an extensive survey of the thermomenter stations in the US and has found considerable discrepancies from specifications for the sites. Virtually all these discrepancies lead to an over reading of what the actual temperature is. Anthony indicates that almost 90% of stations have defects. Now if Anthony is correct, this means that temperature recordings for the US are overstated. The corollary to this is that the US has not warmed as much as claimed. If we have many questions about the US stations what are the rest of the world's stations like? It may well be that the claims of warming in the 20th century may be well overstated. We must remember that most of the warming that ocurred since the start of the industrial revolution happened before 1900.
Thank you very much Dr. Christie, yours is the voice of "reason", sadly, for the people of this planet, you are in the very small minority.
Guys, your comments are making my brain hurt (except Kim and Sean). Let's not talk about theories as fact.
Dr. Christy, wikipedia calls you an expert on paleoclimate. What is your opinion on the hockey stick? Actually, I would love to see an interview focusing just on the ramifications of his answer to that question as pertains to historical records, archeological inferences, supposed multi-decadal regional climate shifts, the relevance of 1000 years vs. 10,000 years, tree rings of different types vs. varves vs. ice cores.
Dr. Christy, how complete is the coverage in each of the global temperature datasets, and how much is interpolated? How much do the interpolated regions impact the overall numbers?
Dr. Christy, what is your best guess for the percent of global warming seen in the 20th century due to CO2 and aerosol emissions from humans?
Thanks for this great interview.. My question is more related to the our Govt's itchy trigger finger to regulate ever more based upon the so-called GHG "pollution".. Congress seems to feel the need to "do something" without fully understanding how far we have come in recent decades... Our cars and trucks are very clean. My belief is that the majority of Americans have no idea how clean we are already.. My question is; how can scientists explain to Congress that we aren't going to "flip a switch" overnight to a new fuel source for transportation and heating and that we need to continue as we have for 20th century moving away from wood and coal in your homes to a cleaner brighter future..... I simply feel politicians are fooling themselves while fooling us with the notion we are gonna "get off oil" now... Ain't gonna happen...
In terms of natural variability, I would be interested to hear Dr. Christy's thoughts on what appears to me to be one of the 800lb gorillas in the climate change room. One I suspect no one here has thought anything about. How long will the Holocene last? What will the end Holocene look like? The Holocene is the latest of the post Mid Pleistocene interglacials. Five of the last 6 such interglacials have each lasted about 10-12k years, or half a precessional cycle long. The Holocene is presently about 11,500 years old now. Proxy data confirms that the end interglacials are periods of rapid swings in climate as the system changes gears to a glacial. The end Eemain appears to have had at least two rapid thermal maxima and a 6 meter rise in sea level before it began to cycle into the Wisconsin ice age. This brings the argument to signal to noise. If the natural noise can produce rapid temperature and sea level changes (up to ~20 feet) how will we "see" an AGW "signal"?
I guess I see why Tom gets paid to write and I don't.
My post last night was incoherent, except where it was unintentionally insulting.
My apologies to Dr. Christy. What I meant to say was that I knew he was an expert on satellite temperature measurement, but I did not know he was also interested in paleoclimatology. I've read many things by him on the subject of UAH and RSS, not so much about the hockey stick. I would love to read his take on what I think is the most controversial subject in climate science.
Do you realise that if all the climate scientists approached their research in the manner of Dr. Christy and a number of others we would not be having these discussions. We would however be far better prepared for what ever the climate instead of being so distracted.
Thank you Dr.Christy for your integrity and your willingness to share your thoughts.
My concerns relate to the looming food shortages if the SC24 and SC25 prove to be as weak as many solar physicists predict. The effort wasted on demonizing carbon could have been better spent.
This was an excellent interview with a very reasonable expert. Over stating the results of "scientific studies" is the daily fare of the alarmists. I have read much on this topic and I cannot yet be even worried much less alarmed. The oceans seem to have a massive effect on our climate yet the study of oceans takes a back seat to the "study" of the atmosphere. Solar activity and sub-oceanic volcanic activity emit more warming force than is being measured or considered. All the heat generated by mankind since the beginning pales alongside these two sources. So far nothing noticable or alarming has occurred in my 66 years on planet earth. I look forward to the next decade or two without fear. I am glad Dr. Christy does too.
Hi Dr. Christy
One point I would like to make and to my knowledge this point has not been addressed. The temperature/CO2 record show that a CO2 rise follows a temperature rise. Thus, CO2 levels are a function of temperature.
The correlation is that CO2 rises follow temperature rises by 800-1200 years. Could it be that the CO2 changes we are seeing at the moment are a result of the Mediaeval Warm Period (MWP)? The MWP was about 1,000 years ago.
Dr Christy's complete presentation to the IAC may be read at:
pielkeclimatesci.files.wordpress.com/2010/06/christyjr_iac_100615.pdf
and Roger Pielke's comments are at:
pielkeclimatesci.wordpress.com/2010/06/18/john-christy-presentation-on-the-ipcc-assessment-process/
This is a very good question that students have asked me: "Could it be that the CO2 changes we are seeing at the moment are a result of the Mediaeval Warm Period (MWP)?"
I hope Dr. Christe answers.
See our Climate Scientists Register at tinyurl[dot]com/2es3rqx
Tom Harris
ICSC - Canada
Examiner: How hopeful are you that our actions can reduce emissions further? Tom, Why would we care about CO2 emissions. I know that is what you are talking about. You still feel we need to reduce CO2 emissions. CO2 is plantfood.
Tom Harris and John Westman:
The CO2 rise observed now is not related to the Medieval Warm Period or the Little Ice Age. There are several complementary ways to show conclusively that the increase in CO2 is primarily due to fossil fuel energy production. The Suess effect, the congruence of the Keeling curve and simple estimates of fossil fuel use (www.skepticalscience.com/co2-coming-from-ocean.htm), and the fact that the oceans are absorbing CO2 (www.skepticalscience.com/warming-co2-rise.htm) are some ways to demonstrate this.
Dr. Christy: your satellite data analysis provides a decadal trend that is consistent with other analyses of satellite LT and surface data. This trend is on the order of 0.15 - 0.2 deg C
per decade, which would be 1.5 to 2 C per century (if it does not accelerate).
1. Is this trend real or illusory?
2. If real, is the primary cause natural variability, or an environmental forcing?
3. Should the global community consider the causes and effects of this trend in planning for the Earth's environmental future?
4. If the primary cause of the trend is eventually ascribed with unassailable certainty to human activities*, should these activities be altered significantly?
*rather than the current extensive compendium of scientific data indicating this cause-and-effect with provisional strong certainty
questions for the next interview: 1) How would you change gov. funding for climate research? 2) What current data gathering projects are likely toshed the greatest insights for climate science. 3) What new projects would you propose to increase climate data? 4) What is your view of the solar-wind cosmic ray theory and what results from the CERN tests would influence your view one way or another?
My question for Dr. Christy is, why do we not see short-term projections from GCMs? Given the amount of historical data on record, it should be fairly simple to start a run 50 years ago and extrapolate 5 or 10 or 15 years into the future. It seems a shame that the models can't be evaluated in this way.
Re Oakden Wolf about the MWP and CO2:
I have one other question to put out there--do we know what would be happening to current CO2 levels if humans were not putting out so much CO2? I know that the oceans are currently absorbing about half of the CO2 we put into the air, but what if the reason they are only absorbing half is that the proposed MWP-related CO2 release is pushing in the other direction? I don't even know if finding that out is possible, but it seems an interesting question.
Bill Stolzfus:
Sorry for replying slowly, I don't check here everyday. Virtually all the carbon cycle inventories I've ever seen indicate that were it not for anthropogenic CO2 emissions, atmospheric CO2 would be decreasing (i.e., fluxes into sinks are greater than fluxes out of sources). This is particularly true of the oceans, which are well-characterized; the oceans are a net sink. Thus, there is no MWP-related CO2 flux to the atmosphere "pushing in the other direction", as you phrased it. That's partly provable by seeing the difference in the Pacific CO2 flux in El Nino and La Nina years -- bigger changes there than anything a supposed MWP "recovery" could cause.
Have you been contacted by the Australian Government Climate Committee in 2011 so that your balanced opinion has been taken into consideration.
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