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Daniel Bailey at 11:34 AM on 6 July 2013There is no consensus
I've cobbled the following list together from a variety of sources and persons. Apologies, but it's been too long to remember whom they were for proper attribution:
The IPCC’s conclusion that most of the warming since 1950 is very likely due to human emissions of greenhouse gases and has been endorsed by this great cloud of witnesses:the National Academy of Sciences,
http://www.nap.edu/openbook.php?record_id=10139&page=1the National Aeronautics and Space Administration,
http://climate.nasa.gov/causes/the National Center for Atmospheric Research,
http://eo.ucar.edu/basics/cc_1.htmlthe National Oceanic and Atmospheric Administration,
http://www.ncdc.noaa.gov/oa/climate/globalwarming.htmlthe American Geophysical Union,
http://www.agu.org/sci_pol/positions/climate_change2008.shtmlthe American Institute of Physics,
http://www.aip.org/fyi/2004/042.html
http://www.aip.org/gov/policy12.htmlthe American Physical Society,
http://www.aps.org/policy/statements/07_1.cfmthe American Meteorological Society,
http://www.ametsoc.org/POLICY/climatechangeresearch_2003.html
http://www.ametsoc.org/policy/2007climatechange.html
http://www.ametsoc.org/policy/2012climatechange.htmlthe American Statistical Association,
http://www.amstat.org/news/climatechange.cfmthe American Association for the Advancement of Science,
http://www.aaas.org/news/press_room/climate_change/the Federation of American Scientists,
http://www.fas.org/press/statements/_docs/08grand_challenges.htmlthe American Quaternary Association,
http://www.inqua.org/documents/QP%2016-2.pdf
http://www.agu.org/fora/eos/pdfs/2006EO360008.pdfthe American Society of Agronomy,
https://www.soils.org/files/science-policy/asa-cssa-sssa-climate-change-policy-statement.pdfthe Crop Science Society of America,
https://www.soils.org/files/science-policy/asa-cssa-sssa-climate-change-policy-statement.pdfthe Soil Science Society of America,
https://www.soils.org/files/science-policy/asa-cssa-sssa-climate-change-policy-statement.pdfthe American Astronomical Society,
http://aas.org/governance/resolutions.php%23climate#climatethe American Chemical Society,
http://portal.acs.org/portal/fileFetch/C/WPCP_011538/pdf/WPCP_011538.pdfthe Geological Society of America,
http://www.geosociety.org/positions/position10.htmthe American Institute of Biological Sciences,
http://www.nationalacademies.org/includes/G8+5energy-climate09.pdfthe American Society for Microbiology,
http://www.asm.org/images/docfilename/0000006005/globalwarming%5B1%5D.pdfthe Society of American Foresters,
http://www.safnet.org/fp/documents/climate_change_expires12-8-2013.pdf
http://www.safnet.org/publications/jof/jof_cctf.pdfthe Australian Institute of Physics,
http://www.aip.org.au/scipolicy/Science%20Policy.pdfthe Australian Meteorological and Oceanographic Society,
http://www.amos.org.au/documents/item/26the Australian Bureau of Meteorology and the CSIRO,
http://www.csiro.au/files/files/pvfo.pdfthe Geological Society of Australia,
the Federation of Australian Scientific and Technological Societies,
http://www.fasts.org/images/policy-discussion/statement-climate-change.pdfthe Australian Coral Reef Society,
http://www.australiancoralreefsociety.org/c/document_library/get_file?uuid=5d093a51-a77e-4ae0-bd9f-67e459d57ac1&groupId=10136the Royal Meteorological Society,
http://www.rmets.org/news/detail.php?ID=332the British Antarctic Survey,
http://www.antarctica.ac.uk/bas_research/science/climate/position-statement.phpthe Geological Society of London,
http://www.geolsoc.org.uk/gsl/views/policy_statements/page7426.htmlthe Society of Biology (UK),
http://www.societyofbiology.org/policy/policy-issues/climate-changethe Canadian Foundation for Climate and Atmospheric Sciences,
the Canadian Meteorological and Oceanographic Society,
http://www.cmos.ca/climatechangepole.htmlthe Royal Society of New Zealand,
http://www.royalsociety.org.nz/organisation/panels/climate/climate-change-statement/the Polish Academy of Sciences,
the European Science Foundation,
the European Geosciences Union,
http://www.egu.eu/statements/position-statement-of-the-divisions-of-atmospheric-and-climate-sciences-7-july-2005.html
http://www.egu.eu/statements/egu-position-statement-on-ocean-acidification.htmlthe European Physical Society,
http://nuclear.epsdivisions.org/Reports/eps-position-paper-energy-for-the-futurethe European Federation of Geologists,
the Network of African Science Academies,
http://www.interacademies.net/File.aspx?id=4825the International Union for Quaternary Research,
http://www.inqua.org/documents/iscc.pdfthe International Union of Geodesy and Geophysics,
http://www.iugg.org/resolutions/perugia07.pdfthe Wildlife Society (International),
http://joomla.wildlife.org/documents/positionstatements/35-Global%20Climate%20Change%20and%20Wildlife.pdfand the World Meteorological Organization.
http://www.wmo.ch/pages/mediacentre/statann/documents/SG21_2006_E.pdfThere aren’t any national or international scientific societies disputing the conclusion that most of the warming since 1950 is very likely to be due to human emissions of greenhouse gases, though a few are non-committal.
The last organization to oppose this conclusion was the American Association of Petroleum Geologists (AAPG). They changed their position statement in 2007 to a non-committal position because they recognized that AAPG doesn’t have experience or credibility in the field of climate change and wisely said “… as a group we have no particular claim to knowledge of global atmospheric geophysics through either our education or our daily professional work.”
http://en.wikipedia.org/wiki/Scientific_opinion_on_climate_change#Non-committal_statements
http://dpa.aapg.org/gac/statements/climatechange.pdf
http://64.207.34.58/StaticContent/3/TPGs/2010_TPGMarApr.pdfThere are people maintaining lists of these orgainzations, but I'll have to try and dig up the links. Been about 3 years since I lasted looked at them...
The now-defunct LogicalScience.com website maintained a seemingly-complete listing, but it has gone into the great Internet Twilight zone. However, the most recent archive of the site can be found:
http://web.archive.org/web/20111130013640
Moderator Response:[RH] Fixed the few super long URL's that were breaking the page formatting.
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Alpinist at 08:55 AM on 6 July 2013Two Expert — and Diverging — Views on Arctic’s Impact on Weather ‘Whiplash’
Jeff Masters site has had several recent posts on this as well including this: http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2452 from just a couple days ago.
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Chris G at 05:44 AM on 6 July 2013Two Expert — and Diverging — Views on Arctic’s Impact on Weather ‘Whiplash’
Not an expert, but I could follow both arguments; I also found Dr. Francis' to be more compelling.
As I understand it: The jet stream(s) are not driving forces; they are a product of the large circulation patterns for polar, intertropical, and Hadley cellss; they exist where the circulation patterns meet. Physics predicts, and we have observed, that warming anamolies increase toward the poles. The waves in the jet stream are largely a result of the different speeds of the larger circulation patterns. When air (or any fluid) flows past other air, turbulence is created. For less deltas, the turbulence has larger, slower waves. I suppose an analogy could be that shorter frequency waves have higher energy than longer frequency waves; and in this case the energy in the wave is a product of the energy differences between the air masses in the different circulation patterns.
If someone has a better understanding, I'd be glad to hear it.
So, if this is by-and-large correct, then we would expect to see changes in the jet stream waves (amplitude, frequency, and location) with any lessoning of temperature gradient between equator and pole. The Arctic ice is particularly interesting if you think of it as an temperature buffer. There is a fair amount of energy delta between several million cubic meters of ice and the same mass of water, at the same temperature. So, I think that there would be a change in the jet stream pattern regardless of if the Arctic were land or sea, but I suspect that the difference is enhanced by the larger differences we are seeing being ice minimum and ice maximum.
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citizenschallenge at 01:11 AM on 6 July 2013Two Expert — and Diverging — Views on Arctic’s Impact on Weather ‘Whiplash’
Fascinating article, thanks for printing it.
And thanks chriskoz for voicing my thought:
"Note how (Trenbirth) says "there might be influence somewhere in Europe, for example, but not over entire NH". To which I may reply: well, the same jetstream flies over Canada US and in Europe, why do you think America is "immune" to it?
==============
And sorry for doing this, but it is only slightly off topic considering how science skeptics love pointing out the 1920/30s arctic warming (where they fail to mention the warming was rather localized, originating around Spitsbergen) trying to imply that there is nothing unusual about current events.
I've been reading: "The Arctic Warming 1919 to 1939" by: Arnd Bernaerts
http://www.arctic-heats-up.com/pdf/chapter_8.pdf
Which has introduced me to the notion that intense navel activity caused a great deal of ocean mixing, disrupting the thermohaline current, and leading to the freak warming event that started off Spitsbergen and spread outward from there:
" a long barrage between the Orkney Islands and Norway ... (USA and UK mines laid) 73.000 mines __about 5,000 exploded prematurely soon after laying __20,000 mines were disposed of while the work was in progress __from the remaining ca. 50,000 mines __more than 30,000 mines were already ‘gone’ in spring 1919, either drifted away, or exploded during winter storms; __rest 20,000 were swept in 1919." {ch.8 p.94}
In all something like 200,000 mines were laid in various North Atlantic locations.
~ ~ ~
As for ships and U-boats:
"The situation became dramatic when U-boats destroyed more ships than Britain could build in early 1917. In April 1917, the same total rate of the previous annual rate of 1916, ca. 850,000 tons, was destroyed by U-boats. In April 1917, Britain together with the Allies lost 10 vessels every day. During the year of 1917, U-boats alone sank 6,200,000 tons, which means more than 3000 ships, and, during the war months of 1918, another 2,500,000 ship tonnage. The total loss of the Allies ship tonnage during WWI is of about 12,000,000 tons, namely 5,200 vessels. The total loss of the Allies together with the Axis naval vessels (battle ships, cruisers, destroyers, sub-marines, and other naval ships) amounted to 650, respectively 1,200,000 tons." {ch.8 p.88}
~ ~ ~ ~ ~ ~ ~
It's one of those thoughts that at first blush is way out there, but then on reflection and considering the new found appreciation for the amount of deep ocean churning whales and other sea creatures produce as they dive to deep depths then return to surface (http://www.biogeosciences-discuss.net/9/8387/2012/bgd-9-8387-2012.html) - it doesn't seem so far fetched.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I'm curious how has the scientific community reacted to Bernaerts' hypothesis?
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DSL at 23:32 PM on 5 July 2013Nils-Axel Mörner is Wrong About Sea Level Rise
Klaus, perhaps after Morner has addressed his integrity here, he can go to Open Mind and address this.
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Boswarm at 22:42 PM on 5 July 2013Peak Water, Peak Oil…Now, Peak Soil?
Stephen Leahy,
I did not infer or imply you made this stuff up?
Read my comment again. It's the bits left out that got to me. Then you say:
"Iceland has not recovered, it remains Europe's largest desert despite the amazing efforts of the soil cons service. "
It has recovered and adapting to the new soil conditions, and as it warms, the position will improve. The statistics prove this. See the references in my previous coment especially www.bondi.is
"FYI It is a 1000 word article, not a transcript of 3 days of talks" - I know what you wrote, I have all the transcripts from the conference, yet so much was omitted in the true story of Iceland farming.
- Fertilizer usage reduced since 1981
- Barley 15,000 tonnes per year for zero in 1970
- Beef cattle increase to 2011
- Horse breeding doubled
- Pigs increase X 6
- Laying Hens plus 50,000 since 1970.
What these figures exhibit is a shift from dairy and sheep to other forms.
It's called adapting, not peak soil. Iceland is becoming one of the most unique farming communities in the world with now less than 6.5% of the population producing more agricultural and pastoral product than 77% of the population did in 1901. Change and adaption is what Iceland farmers are great at. If you visited the Westfjords you would have seen a great change from an old farming practices to the new.
Have a look at the constant change between agriculture and pastoral - it's called adaption.
Your article was a correct representation of the conference, but needed a lot of information regarding the true nature of the industry in Iceland to create balance.
I am sorry if I have upset you in my comments above and here. I have seen Iceland over many years, and it is improving greatly, except for the fact that the good farmers, agricultualists and pastoralists are aging and not been replaced. It should be retiltled - PEAK FARMER.
And if vrooomie had any manners like you have Stephen, he would have asked similar questions. We have to keep fighting to reduce the carbon pollution or we will all be at peak END.
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chriskoz at 21:23 PM on 5 July 20132001-2010, A Decade of Climate Extremes
Cornelius@7,
"dramatic music" is for large, poorly educated audience. Like most TV shows, they must add some "drama" to entice audience. Otherwise they would go out of business if they'd left with viewers like you & me only.
I think it is getting better: not so long ago they used to entice audience by falsely pretending the existence of "debate": i.e. showing Monckton, Bob Carter and even Tony Abbott arguing this science is "crap". No need to say that none of those characters (with the exception of Bob Carter) are even worth mentioning along the names of the scientists, let alone give then any air time. In case of Bob Carter, if giving him any time, it is mandatory to mention his personal bias due to regular payments from The Heartland Institute in appreciation for his scientific opinion. Otherwise his apearance is misleading for poorly educatred audience.
But not a hint of any "skepticism" in this program. Let's hope this change is for good, at least in Catalyst.
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chriskoz at 20:38 PM on 5 July 2013Two Expert — and Diverging — Views on Arctic’s Impact on Weather ‘Whiplash’
I don't think Kevin's & Jennifer's views are diverging by much. Kevin does not contradict the theory of meandering jetstream's signifficance on NH weather, he's just a bit skeptic (in a good sense) and is looking for more evidence. Note how he sais "there might be influence somewhere in Europe, for example, but not over entire NH". To which I may reply: well, the same jetstream flies over Canada US and in Europe, why do you think America is "immune" to it?
Personally, I give more edge to Jennifer's view because she's more knowledgeable expert in this particular topic. And some evidence confirming meandering jetstream's theory at work in America (e.g. tropical cyclone Sandy) do exist to back her.
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Cornelius Breadbasket at 18:03 PM on 5 July 20132001-2010, A Decade of Climate Extremes
mikeh1 @ 5
I'll share this one. I'd prefer it without the dramatic music - but it is a very well put together documentary. Thank you!
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johncl at 17:58 PM on 5 July 2013Climate change science: what’s in a name?
I do believe the next glacial period is estimated to be around 50000 years from now if the natural forcings (Milankovitch cycles) are the main driver. The question remains though whether the new state of the biosphere with a substantial higher CO2 concentration (so far 40% over what it should be) will even allow the planet to cool down enough for serious glaciation. Most likely it will cool down though as the tilt surely must have a substantial effect on the amount of energy absorbed (but I am really only guessing here). Our CO2 emissions will most likely not go down much in the coming decades and every year really reduces the chance for these natural forcings to overcome the artificial injection of insulation in the atmosphere. But they will still come "on top", including the weather patterns, so I wonder how the next major El Niño will affect us. No doubt another round of high scores.
About the terms, I still think AGW is the correct term as its our deliberate warming of the planet which is of essence here, climate change is just one effect of this. And as villabolo say here the effect it has on food production is probably the immediate one we will notice, partially also because there are so many of us on the planet now. Add a bit of energy crisis due to oil shortage and the "green revolution" goes *poof*, and we are back to being more relient on whatever energy the soil and the sun gives our crops. Some freak weather incidents on top (due to e.g. a messed up jetstream) will then add the little extra challenge. I say we live in interesting times...
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skymccain at 16:34 PM on 5 July 2013Climate change science: what’s in a name?
Thank you KR.
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Bert from Eltham at 12:31 PM on 5 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
Bear with me.
The mindless universe started with inflation.
Soon after cooling enough atoms of H, and He and a bit of Li formed.
Some of these atoms some time later gravitationally collapsed into stars.
These early stars were responsible for nucleosynthesis of heavier nuclei.
It was only supernovae that actually produced nuclei above Iron 56.
All this newly formed matter that was strewn everywhere then finally at some cool places formed new stars and planets.
The third stone from the Sun was geologically active with ordinary chemistry to make a near habitable planet. The above is very good article.
Early mono cellular life transformed the oceans and atmosphere and forever changed the simple chemistry that was in effect up till then and it took four billion years!
Finally multi cellular life evolved. Until we came along. We are all trashing our only home because of greed.
Worth a look.
http://www.youtube.com/watch?v=9nnwvoH-4XI
Bert
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mikeh1 at 09:18 AM on 5 July 20132001-2010, A Decade of Climate Extremes
Moderator - the following may be a better link to the Catalyst story. The mp4 works well on a tablet but not so well on a desktop.
http://www.abc.net.au/catalyst/stories/3796205.htm
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mikeh1 at 09:15 AM on 5 July 20132001-2010, A Decade of Climate Extremes
The following is a link to last night's excellent Australian ABC Catalyst science program on extreme weather.
http://mpegmedia.abc.net.au/tv/catalyst/catalyst_14_11_wildweather.mp4
It includes interviews with the following climate scientists.
Dr Erich Fischer, Institute for Atmospheric and Climate Science, ETH
Dr Karl Braganza, Australian Bureau of Meteorology
Dr Lisa Alexander, Climate Change Research Centre, UNSW
Dr Susan Wijffels, Marine and Atmospheric Research, CSIRO
Professor Jennifer Francis, Institute of Marine and Coastal Sciences, Rutgers University -
KR at 09:01 AM on 5 July 2013Climate change science: what’s in a name?
skymccain - "...why we have not entered the cooling part of this glacial/interglacial cycle yet."
We were starting the cooling portion of this cycle, with Holocene temperatures starting to decline, until the Industrial Revolution. Now, apparently, Milankovitch cycle cooling is off the table for many thousands of years.
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skymccain at 08:23 AM on 5 July 2013Climate change science: what’s in a name?
I especially like this post. The comments remind me that I would like to read more about why we have not entered the cooling part of this glacial/interglacial cycle yet. There has been so much written on why the warming. That's important, don't get me wrong, but it may also help to identify the factors that in the past triggered a cooling trend. I won't play completely ignorant as I have studied the Berger insolation data and have formed my own opinion. However, I am not a professional and have no standing so would like to hear professionals explain when we might look forward to the trip toward another ice age. What do you think?
Best wishes, Sky
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Dikran Marsupial at 06:30 AM on 5 July 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
KK Tung wrote " While Dikran may disagree with my summary, I think he has failed to come up with an example where our procedure fails to yield the right answer within the 95% confidence interval (CI) most of the time. "
This is simply incorrect. In the example here, the linear trend due to the anthropogenic component is estimated by the MLR procedure to be 0.0019 +/- 0.00039, the true value is 0.003, which is not in the 95% confidence interval. In this example, the MLR procedure underestimetes the anthropogenic component and the difference is statistically significant. Sadly there seems little point in continuing the discussion if this cannot be acknowledged and accepted, so I will leave it at that, so as not to distract from Prof. Tung's discussion with Dumb Scientist.
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Cornelius Breadbasket at 05:47 AM on 5 July 20132001-2010, A Decade of Climate Extremes
shoymore @ 3
You are right. On the BBC there is rarely a mention of CO2 or human influence - whether it is the changing of the jet-stream, the melting of the Arctic or extreme weather (a notable exception being the piece I linked to). I feel that this is because so many contrarians have made life difficult for good journalists like Richard Black (who was solidly under attack by 'climate sceptics' and has now left the BBC) that they are terrified of being victimised in a similar way. Apologies if this is off topic.
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shoyemore at 05:05 AM on 5 July 20132001-2010, A Decade of Climate Extremes
BBC did do a good news report last night on their national evening bulletin, with a reporter speaking about the extreme heat in Death Valley.
However, CO2 was not mentioned. The reporter also said "Global temperature rise has stalled, but it is the extremes that matter, and they will continue."
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John Hartz at 04:36 AM on 5 July 2013Climate change science: what’s in a name?
What's missing from the OP and the discussion thread to date is a basic understanding of how climate scientists define the Earth's "climate system."
Per the SkS Glosary and the IPCC, "climate system" is defined to be:
The climate system is the highly complex system consisting of five major components: the atmosphere, the hydrosphere, the cryosphere, the land surface and the biosphere, and the interactions between them. The climate system evolves in time under the influence of its own internal dynamics and because of external forcings such as volcanic eruptions, solar variations and anthropogenic forcings such as the changing composition of the atmosphere and land use change.
Definition courtesy of IPCC AR4.
The above is a working definition that we all should adhere to.
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villabolo at 04:26 AM on 5 July 2013Climate change science: what’s in a name?
Johncl @7
"What I often feel is missing from the terms is the effect beside climate change. There is no doubt the chance of a major "biosphere change" - not not only climate. I believe many people dont consider a bit more wind in their hair now and then a problem".
Unfortunately the general public will consider the term "biosphere change" as too abstract and scientific sounding. Also, most people are inured to hearing words like environment and nature.
The only way to get their attention is to mention the destructive effect of global warming on crops and food prices. That is the only "nature" that most of the general public will be concerned about.
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grindupBaker at 03:03 AM on 5 July 2013Climate change science: what’s in a name?
I suggest not messing around with the basic phrase in the terminology because Anthropogenic Global Warming is complete enough and accurate enough. The issue is in explaining clearly what happens, has happened, will happen. Messing around with phrases at some point becomes treating other people like children (or, even worse, like consumers). Adopt supplemental detail phrases if necessary and provided they are clear, correct & concise. If you can make a case that significant potential energy or kinetic energy increase has occurred then maybe. I gave it a quick rough shot with sea level rise & more water in air (potential) and tried to find ocean current info (kinetic) but it's negligible. So why "energy" ? Pedantic nonsense.
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Smith at 02:52 AM on 5 July 2013Climate change science: what’s in a name?
I’m cautious about introducing novel terms, because it can be counter-productive, making things even more confusing despite good intentions.
In light of this remark, is the use of the term "Climate Change Science" a deliberate departure from the more traditional and common term "Climate Science"? If so, could you please illustrate the distinction?
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John Hartz at 02:27 AM on 5 July 20132001-2010, A Decade of Climate Extremes
Cornelius Breadbasket #1:
As should be the case with a report of this importance, MSM outlets throughout the world are publishing/posting articles about the findings contained in the WMO report, The Global Climate 2001-2010, A Decade of Climate Extremes.
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KK Tung at 02:21 AM on 5 July 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
On the “thermodynamics argument”: Dumb Scientist has repeatedly touted the thermodynamic argument as putting an upper limit on internal variability:
"Again, attribution is really a thermodynamics problem that needs to be calculated in terms of energy, not curve-fitting temperature timeseries. Your curve-fitting claim that ~40% of the surface warming over the last 50 years can be attributed to a single mode of internal variability contradicts Isaac Held and Huber and Knutti 2012 who used thermodynamics to conclude that all modes of internal variability couldn't be responsible for more than about 25% of this surface warming."
First, attribution is not necessarily a thermodynamics problem. The method adopted by IPCC AR4, the “optimal fingerprint detection and attribution method”. “is based on a regression of the observation onto model simulated patterns and relies on the spatio-temporal response patterns from different forcings being clearly distinct…..The global energy budget is not necessarily conserved and observed changes in the energy budget are not considered”. This quote came from Huber and Knutti, 2012.
Secondly, none of the published work could put such a tight upper bond on the contribution by internal variability. Huber and Knutti (2010) in Nature Geoscience, mainly used a zonal mean energy balance model of intermediate complexity, meaning a model without ocean dynamics. I believe this model has a diffusive ocean and therefore is not possible to have internal variability beyond a few months: “The energy balance model has no natural interannual variability but is able to reproduce the observed global trend of past temperature and ocean heat uptake”. The model’s ocean heat uptake is constrained using observation in the upper 700 meters: “Ocean heat uptake for 3000 m depth is also larger, but the model is only constrained using data to 700 m depth”. Given these uncertainties, which the authors acknowledged to be large, I would take the results to be a consistency test of models that have simulated the observed warming as almost entirely a response to forcing.
Towards the end of the paper, the authors compared the 50-year linear trends derived from unforced control runs in the CMIP3 models with the observed 50-year trends. These models do have internal ocean variability. ( DS, please note, this part is not based on a thermodynamic argument, but the result was what you referred to as from a thermodynamic argument.) The authors concluded “For global surface temperature it is extremely unlikely (<5% probability) that internal variability contributed more than 26+/-12% and 18+/-9% to the observed trends over the last 50 and 100 years, respectively”. So the “upper bound” is 38% for the last 50 years and 27% for the past 100 years, respectively. Given the uncertainty in the model’s oceans, I do not think these upper bounds rule out our ~40% and ~0% contribution of internal variability to the 50-year and 100-year trends, respectively.
On Isaac Held’s blog#16 that DS refers to as providing an upper bound of 25% for the contribution of internal variability to the surface warming for the past 50 years: We need to recognize that Held is using a very simple two-box ocean model to illustrate the process of energy balance that can be used to constrain the contribution from internal variability. The exact figure of 25% as the upper bound should not be taken too seriously, and it could easily be 40%, given the fact that there is at least a factor of two variation in climate sensitivity in the IPCC models and he picked one particular value of climate sensitivity from one of the GFDL models for illustrative purpose. There were many other simplifying assumptions so that an analytic result could be obtained. One of them is the assumption that ξ, the fraction of temperature change that is forced, remains constant in time as anthropogenic forcing increases. This would have required an increasing magnitude of internal variability. With this assumption, he was able to obtain the following formula:
Ocean heat uptake per unit forcing=Ocean heat uptake per unit forcing as if the entire temperature change were forced - (1-ξ)/ξ.
The last term is due to internal variability. It is negative, because ocean is supplying heat to the atmosphere to be radiated to space. Held estimated a typical value for the first term on the right-hand side to be ~0.3, from which he estimated that if ξ is smaller than 0.75 then the total ocean heat uptake would become negative. So the fraction of warming contributed by internal variability, (1-ξ), cannot be greater than 25% during a period when the ocean heat uptake is positive. This number can easily become ~40% if the forced response is slightly more efficient in storing heat in the ocean. Recent evidence of finding more and more of the forced warming in deeper and deeper ocean layers may suggest that the ocean is more efficient in storing heat than previously thought. Changing 0.3 to 0.5 would yield close to 40% for this upper bound.
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Klaus Flemløse at 02:09 AM on 5 July 2013Nils-Axel Mörner is Wrong About Sea Level Rise
Many thanks to Tom Curtis, Micheal Sweet and DSL for their remarks. I appreciate them.
I have for a long time followed Professor Nils-Axel Mörners attacks against climate scientists and believes that he has gone far over the line of dignity. Prompted by Tom Curtis analysis of Mörner pictures, I have written to Nils-Axel Mörner to get his version of the images and how they should be interpreted. In addition, I asked Mörner to publish all the pictures from his trip so that all indications of fraud and scams can be swept away. He deserves a fair trial. Only by getting his version is possible.Prof Nils-Axel Mörner has informed me, that he was not aware of the discussion about him on Skeptical Sciences. He is now.
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KK Tung at 02:06 AM on 5 July 2013The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
Our exchanges on analysis procedures of a technical nature probably have left most of our readers confused. So let me summarize the major points under debate. Both Dumb Scientist (DS) and Dikran Marsupial have focused on the technical aspects of the Multiple Linear Regression analysis (MLR). This was one of the three data analysis methods that were used on the problem with the aim of deducing the secular trend after removing the oscillatory influence of Atlantic Multi-decadal Oscillation (AMO). Our PNAS paper used two methods, the MLR and the wavelet analysis, and obtained approximately the same result. Previously, Wu et al (2011, Climate Dynamics) used the method of Empirical Mode Decomposition (EMD) and obtained similar results. The EMD method was relatively new, and there were questions on whether other, more commonly used methods could yield the same result. Our PNAS paper was in part (though a small part) trying to reproduce their results using two other methods. The larger aim of our PNAS paper was to argue that the AMO is mostly natural.
Two technical aspects of the MLR have been debated here. Dikran chose to focus on our use of a linear regressor as a placeholder in an intermediate step of the MLR process. This issue was discussed in part 1 of my post, and shown that when the residual is added back as in the published papers (Foster and Rahmstorf (2011), Zhou and Tung (2013), Tung and Zhou (2013)), the sensitivity to the particular intermediate step is greatly reduced. While Dikran may disagree with my summary, I think he has failed to come up with an example where our procedure fails to yield the right answer within the 95% confidence interval (CI) most of the time. Please see my posts 171 and 172 for a summary.
Although I had originally thought that Dumb Scientist also focused on our use of linear regressor as the reason for his assertion that our argument was circular, he later clarified that his focus was on how the definition of the AMO index from the North Atlantic temperature affects the deduced anthropogenic trend. This is a more worthwhile challenge. My collaborator Dr. Zhou and I were interested to follow this debate to find out under what condition the MLR procedure would fail. After all, no empirical method is expected to work under all conditions. So we thank DS for his efforts.
His sequence of examples has evolved into the following: Consider a hypothetical example where we know what the true answer is, and make such an example as realistic as possible (with respect to the correlation between the global mean data and the N. Atlantic data, and the variances in each) so that if the MLR procedure fails in this hypothetical case it is likely to fail in the real case also. The observed temperature (HadCRUT4) warms at the rate of 0.17 C per decade after 1979. This was proposed previously by Foster and Rahmstorf (2011) as the “true anthropogenic trend”. Tung and Zhou (2013), on the other hand, argued that this observed rate of warming includes the rising half cycle of the AMO, which when removed, would yield an anthropogenic trend that is approximately half as large. So the question is, what if the true anthropogenic warming trend is actually 0.17 C per decade in a hypothetical example, will the MLR procedure erroneously say that it is smaller? While I have always maintained that such a theoretical possibility exists, it has been surprisingly difficult to actually come up with an example where MLR fails, and we collectively have gone through examples where the hypothesized anthropogenic warming goes from quadratic to a fifth order polynomial. The example that DS finally came up with consists of a 7th order polynomial for the anthropogenic trend (called human). It has the property that it is warming at 0.17 C per decade post 1979, but no warming before that. The latter fact is unrealistic but necessarily follows from the high order polynomial form assumed for this anthropogenic warming if one uses only analytic forms. There is in addition a 70-year oscillation, which is the AMO (called nature by DS). The global mean temperature is assumed to consist of human + nature + random noise. The N. Atlantic temperature that is used to define an AMO index also consists of these three components but in different proportions. The AMO Index is obtained by linearly detrending the N. Atlantic temperature. The idea is that because the anthopogenic trend is highly nonlinear, linearly detrending the N. Atlantic temperature yields an AMO contaminated by the nonlinear part of the anthropogenic trend. Therefore, if this “AMO” is removed by the MLR procedure, what remains is a more linear trend that is an underestimate of the true nonlinear anthropogenic trend. At least that is the aim of DS, as I understand it.
MLR can fail if the two components that we try to separate (in this case, the AMO and the nonlinear anthropogenic trend) have approximately the same scale, about 35 years, as is the case with DS’s latest example with the high order polynomial. Although the MLR method still can yield the right answer within the 95% CI most of the time (see my posts 178 and 179), it is nevertheless showing symptoms of non-robustness, e.g. sensitivity to the choice of regressors (smoothed vs non smoothed), which neither DS nor we understand at the moment, and we don't have the time to investigate it deeper. In the real case considered in our papers, such sensitivity does not exist and we got approximately the same answer. However, this example is not relevant, despite efforts by DS to make it realistic in other aspects, because we know, based on our current understanding of greenhouse warming, that there has been a warming since 1900. So the time scale for the anthropogenic warming is not 35 years but over 100 years.
The following example remedies this one deficiency in the example by DS that makes his case study less relevant. That is, we still use the hypothesis, as DS did, that the true post-1979 warming is entirely anthropogenic, and so the true human warming rate is 0.17 C per decade. Before that time there is a gentler warming, which is equal to the smoothed secular trend in the observed warming from 1850 to 1979. Everything else remains the same as in DS’s example. We perform 10,000 Monte-Carlo simulations using his method for the MLR. (We think 10,000 is sufficient; there is no need for 100,000 Monte-Carlo simulations.) The MLR procedure obtains the correct answer, defined as within the 95% CI of 0.17 C per decade for the post 1979 trend, most of the time. Specifically, we obtain the correct answer 80% of the time if we use the linear regressor in the intermediate step, 95% of the time correct if we use the QCO2 as the regressor in the intermediate step, and 91% of the time correct if we use human as the regressor, as DS did. Therefore, regardless of the intermediate steps, the MLR is able to successfully separate the components to obtain the “true” answer. The reason that this time the MLR is able to separate the two components is because the anthropogenic warming and the AMO have different time scales, as they should in the real case.
Some details of how we came up with the hypothetical anthropogenic warming follow. As did DS, we tried to be consistent with observation. We start with the HadCRUT4 surface temperature data. We fit it with a 6th order polynomial over the entire period of 1850-2011, instead of just over the period 1979-2011 as DS did. This produces the observed 0.17 C per decade of warming after 1979, the same as in DS. But in contrast, the warming here exists over the entire period, not just after 1979. The polynomial is smoothed by a cubic spline so that the trend is monotonic before 1979. This anthropogenic component will be called human. It is denoted by the red curve in Figure a. To create the AMO the-above-obtained human is subtracted from HadRUT4 data. The difference is smoothed with a 50-90 year wavelet band pass filter. This is the AMO (note: not the AMO Index). This is called nature (denoted by the purple curve in Figure b) and is the counterpart to DS’s 70-year sinusoid.
The global data consists of these two components plus a random noise of standard deviation of 0.1. The AMO Index is created using the N. Atlantic temperature, linearly detrended. For the N. Atlantic temperature, we assume it is composed of an anthropogenic warming given by 0.8*human (since the observed long-term trend in the N. Atlantic is smaller than that in the global mean) and the natural component is 1.4*nature (since the AMO in the N. Atlantic is known to be larger than that in the global mean). The correlation coefficient between the global data and the N. Atlantic data in this synthetic example is 0.74+/-0.06, very close to the observed correlation of 0.79. There is in addition a random noise in the N. Atlantic with standard deviation of 0.15. The synthetic global variance is 0.071+/-0.008 and the synthetic N. Atlantic variance is 0.066+/-0.011, very close to the real variances of 0.07 and 0.05, respectively.
In conclusion, it has been surprisingly difficult to come up with a synthetic data where the MLR method fails to yield the right answer most of the time. The latest example by DS comes closest, but has an unrealistic deficiency. In all the cases considered, none has failed both of our methods, the MLR and the wavelet method. These debates have served the purpose of strengthening our confidence in using these methods, and in the technical correctness of the results that we obtained in our PNAS paper using the two methods, although we should always be on guard for the possible failures of any method we use. It should be pointed out however that none of these technical discussions concerns the larger picture: whether the AMO is forced or natural.
I hope with this summary we can conclude the technical discussion on the MLR procedure, and can now move on to the other threads, such as the “thermodynamic argument”, which supposedly sets an upper limit on how large natural internal variability can be.
Moderator Response:[RH] Fixed image width.
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PluviAL at 01:15 AM on 5 July 2013Climate change science: what’s in a name?
Wonderful observation. I am not use to the term "Energy" yet but it seems to gets at something that needs to be made clear at each step of any discussion. Greater "energy" will affect every weather event. It seems too much emphasis it put on saying any event is not the direct result of climate change. That is incorrect, I don't really know what people mean when they say that. It seems to mean that climate change is supposed to create different weather phenomenon, as in "bad" things. What must be the case is that energy always effects every weather event. I wish there was a way for teachers of weather reporters and reporters in general could make this understanding clear, so that they can disseminate it accordingly. Excellent perception, thanks.
As to preventing determined miss-information industry from misusing the term: maybe, but a liar can always figure a way to twist the mind in perverse ways.
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johncl at 00:42 AM on 5 July 2013Climate change science: what’s in a name?
What I often feel is missing from the terms is the effect beside climate change. There is no doubt the chance of a major "biosphere change" - not not only climate. I believe many people dont consider a bit more wind in their hair now and then a problem - but if the heat and acidification of the seas kill of a lot of oxygen producing phythoplankton then that might grab the attention. The focus on weather incidents is of course natural, but I do believe the general biological effect a warmer planet has on life in all forms is one of more concern.
I like to think if it like, there is a different between a major storm on a lifeless planet, and one on earth - we still have life here, but shouldnt take that for granted if the planet gets excessively hot in the coming centuries. Life is fragile, and climate change is just one of the things that will affect a global warming planet. I think AGW coins the term better than any as its warming (and all of its consequences, weather and biological), AND its caused by the burning of fossil fuels.
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DSL at 00:35 AM on 5 July 2013There is no consensus
participley, I've just gone through all of them. I can't find one that has issued a statement of disagreement. Did I miss one?
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participley at 00:05 AM on 5 July 2013There is no consensus
[-snip-]
Moderator Response:[RH] Your question has been responded to. Reposts of the same question have been deleted.
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Tom Curtis at 23:43 PM on 4 July 2013Nils-Axel Mörner is Wrong About Sea Level Rise
DSL @65, the photo shown @62 is certainly not the "original" version of any part of the photoshoped photo. The rocks in the foreground are different, and the boats in the background are different, not to mention the missing house and tree in the middle distance on the right of the new photo that is absent from the photoshopped photo. It is possible, but not likely that it is a photo of the original tree whose folliage is shown in the photoshopped picture.
Klaus Flemlose @62 on rereading your post I note that you still believe that the tree whose foliage is shown in the photoshopped picture was "cut down". Axel-Morner's claim was that it was uprooted ("torn down") rather than that it was cut down. It is essential to his story that it was uprooted, for if it had been cut down, it would not have been possible to replant it.
The fact that his story requires that the tree be uprooted shows what a work of fiction that story is. Only if erosion has removed almost all soil from around the roots of a tree can it be uprooted without strenuous digging and (preferably) a tractor.
Further, Axel-Morner's account is as follows:
"You know what happened? There came an Australian sealevel team, which was for the IPCC and against me. Then the students pulled down the tree by hand! They destroyed the evidence. What kind of people are those? And we came to launch this film "Doomsday Called Off,” right after that, and the tree was still green. And I heard from the locals that they had seen the people who had pulled it down. So I put it up again, by hand, and made my TV program...."
So not only did these herculean and malicous Australians uproot the tree, but Axel-Morner replanted the tree and then, purportedly, to the photo (explicitly identified as the photoshopped photo in the caption). That being the case, the roots would still be loose in the photo and (given the freshness of the foliage) the marks of the Australians efforts in digging out the tree would still be evident. Neither is the case.
I believe the entire basis of the story of the uprooted tree is to be found in Axel-Morner's imagination. Not only does he find it useful to embellish the envidence via photoshopping, he finds it usefull to slander scientists with complete fictions.
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Non-Scientist at 23:29 PM on 4 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
For the denialists, you'll need to explain
how nearly all geologic records were created by one global flood
and
how all of this occurred within 6124 years.
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DSL at 22:58 PM on 4 July 2013Nils-Axel Mörner is Wrong About Sea Level Rise
Klaus, you say Nils sent you the original, and then you say the one he posted was a double exposure. Double exposure does not occur after the photo has been developed. A double exposure is an original. You should have said, "He sent me a different shot of the same tree, a shot that was not a double exposure." If you know enough to understand what a double exposure is--to the point of believing that it absolves Morner--then you should know that saying "Prof Nil-Axel Mörner has been so kind to e-mail me the original photo" doesn't make sense. You're either trying to play games, or you're incredibly naive, naive enough to trust Morner's "double exposure" explanation without knowing what a double exposure is.
Morner also did not send you the original. He sent you a scan of the developed original, unless he's lying about the double exposure. I seriously doubt that Morner, if he actually took the picture in question, used a film camera, the only type of camera able to create a double exposure (unless the digital camera has an extremely rare firmware error that just happens to occur intermittantly and just happened to occur with this particular, highly-controversial exposure). He's wealthy enough to be able to afford a digital camera capable of performing as well as a film camera.
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michael sweet at 22:15 PM on 4 July 2013Nils-Axel Mörner is Wrong About Sea Level Rise
Klaus,
A heads up to you. People who support obviously false explainations damage their own reputations. Why should I believe anything from someone who supported obviously false proposals? Consider the sourse of the information you present to others as accurate. Why do you believe such claptrap? Why have you been taken twice by the same fraudster? Why would you continue to believe the material on those websites that support this fraud?
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Cornelius Breadbasket at 20:22 PM on 4 July 20132001-2010, A Decade of Climate Extremes
The BBC have a nice little online article on this. However, it did not feature very highly in news broadcasts. I wonder if society is going through the five stages of greif? We've had denial, anger and bargaining and perhaps we are entering depression? After all, who wants to hear bad news? I'd like the zeitgeist to move onto acceptance. There may be ways we can help this.
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Tom Curtis at 20:16 PM on 4 July 2013Nils-Axel Mörner is Wrong About Sea Level Rise
Klaus Flemlose @62:
1) Regardless of the tale told by Nils Axel-Morner, the photo I discuss @55 above was not an double exposure. Double exposure is a technique of exposing the same frame of film twice (or more), thereby creating multiple overlaping images. Unless great care it taken, it will result in ghosting as in the photo below. It will not result in sharp demarcation lines as discussed above. Therefore, there remains no doubt that Nils Axel-Morner edited a photo of a tree by deleting portions of it and grafting sections of other photos to replace those portions that were deleted.
2) It is not possible to positively identify the tree in the new photo as that in either of the photos discussed in my 55 above. There are some similarities, but also some distinct differences. The differences may be because they are different trees, or because the pictures were taken from different angles, or at different times.
Based on the similarity of the background, the new photo probably does show the tree shown here in connection to Axel-Morner's claims. I was previously aware of the photo at the link, but did not previously discuss it as it was not directly claimed to be an identical tree, and was not attributed to Axel-Morner. Given the new claim by Axel-Morner, however, I will point out that the root base of this tree and that in the photoshopped picture are definitely distinct. This can be seen because:
a) The size of the rocks in the foreground are very disimilar;
b) The large flat rock on the left of frame and near the tree in both pictures is dissimilar in shape; and
c) The root base of the tree in the new photo is much thicker than that in the photoshopped picture.
3) It is easy to see why Axel-Morner has been using the photoshopped picture rather than the one he has just sent you. The picture he has sent you clearly shows an erosional face in the current tidal zone. It also shows the nearest tree to the one in the center of the photo to also have erosion undercutting its roots. Finally, it shows a slab of concrete lying partially within the tidal zone, and clearly undercut by wave action. All three are indications of rising sea levels at that location.
Until Nils Axel-Morner gives a clear account of how he photoshopped the picture @55, shows us all three pictures he used in doing so, and gives a clear account of why he did so, the only sensible thing to do is to treat this as an example of fraud, and to disregard any "evidence" on which we are reliant on Axel-Morner as our informant. Brushing of the incident with patently absurd claims (ie, that the photo resulted from double exposure) only calls into further question his trustworthiness.
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Klaus Flemløse at 15:20 PM on 4 July 2013Nils-Axel Mörner is Wrong About Sea Level Rise
Prof Nil-Axel Mörner has been so kind to e-mail me the original photo. The photo shown in post #55 was a double exposure, not a photo shop picture.
It is very unfortunate, that prof Nils-Axel Mörner published a double-exposed image, thereby creating a myth about fraud and deception.
The only way to remove any doubt is to publish as much as possible of the documentation before and after the tree have been cut down.
Moderator Response:[DB] Adjusted image width
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DSL at 12:20 PM on 4 July 2013Climate change science: what’s in a name?
I often explain it thusly:
"'Global warming' refers to temperature increase, but climate is much more than temperature. It's also wind, rain, snow, ocean currents, etc. Climate change is change in all of those elements as a result of increased temperature. It's not that everything stays the same but gets hotter. Everything changes--it gets hotter, winds change, the jet stream changes, precipitation changes, ocean currents change: climate changes."
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villabolo at 10:52 AM on 4 July 2013Climate change science: what’s in a name?
Some short answers and talking points that could be understood at a High School level:
In order to explain the difference between Global Warming and Climate Change we can say:
"Global Warming is the cause, Climate Change is the result."
In order to give the shortest answer possible to the issue of our erratic weather we can say:
"The Earth is 1.4 degrees Fahrenheit higher than before while the Arctic is 3-5F and up to 10-18F above normal at certain times and places. This creates a chain reaction of events that give us cold winters and hot summers. However the heat records exceed the cold records."
In order to grab people's attention to the results of Global Warming we can say:
"When the Arctic Ocean loses its ice we start to lose our crops due to severe weather."
In order to explain the leveling off of temperatures we can say:
"Temperatures rose in 1978 and then leveled off followed by another rise in 1998 which also leveled off even though the sun started cooling off in 2002 and went low in 2010. Now that the sun is getting back up to normal we're going to get even higher temperatures."
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Chris G at 09:26 AM on 4 July 2013Climate change science: what’s in a name?
Using the word 'energy' instead of 'heat': Yes, the tradeoff between energy not being as salient as heat (to the layman) and heat not really capturing the meaning correctly is most often worth it.
I also agree that a fair percentage of the contrarian arguments I see are a result of the person believing that the simple explanation implies something it does not. Possibly they are motivated to find flaws with the explanation and so interpret an ambiguous, simple explanation in the least favorable way.
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Rob Honeycutt at 08:00 AM on 4 July 2013There is no consensus
participley... The wiki page on the scientific opinion on climate change they have this statement regarding dissenting opinions:
"As of 2007, when the American Association of Petroleum Geologists released a revised statement,[11] no scientific body of national or international standing rejected the findings of human-induced effects on climate change.[10][12]"
If anyone can find a legitimately recognised scientific body that rejects climate change, I think everyone here would be interested to know about it.
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DSL at 07:23 AM on 4 July 2013There is no consensus
I should also point out that it's unlikely that any organization of professional scientists would actually issue a statement rejecting the theory. Such a move would require evidence, and no such evidence exists.
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DSL at 07:19 AM on 4 July 2013There is no consensus
Participley, as far as I know, no one has published a complete list of scientific organizations' positions on AGW. However, the professional denial industry hasn't located any organizations that disagree, and they'd be the ones most anxious to find such an organization. Perhaps you can locate one?
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william5331 at 06:29 AM on 4 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
Our decendants a few thousand years from now will be grateful for the geological carbon sink but we need to encourage and preserve carbon sinks that act a tad quicker if we are to live to leave such decendants. Fabulous article.
http://mtkass.blogspot.co.nz/2012/02/carbon-sinks.html
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Rob Painting at 06:10 AM on 4 July 20134 Hiroshima bombs worth of heat per second
arncliffe - the thin cool-skin layer of the ocean already is an insulating barrier. Warming the atmosphere, through additonal greenhouse gas emissions, simply increases the efficiency of that insulating barrier.
Reduced equatorial cloud cover during La Nina (due to the cooler sea surface temperature), combined with the strong upwelling (Ekman suction) in the eastern equatorial Pacific, does indeed lead to greater warming of the ocean - because it's bringing cool subsurface water to the surface, where it can be heated by the sun. I briefly touched on that in this post: Search For 'Missing Heat' Confirms More Global Warming 'In The Pipeline'.
Once the posts explaining the wind-driven ocean circulation and deep ocean warming are completed, it will be definitely worthwhile explaining how all the pieces of the puzzle fit together. Many readers overlook the obvious implications.
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participley at 05:47 AM on 4 July 2013There is no consensus
"There are no national or major scientific institutions anywhere in the world that dispute the theory of anthropogenic climate change. Not one."
Is there a reference for this statement ?
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rockytom at 05:32 AM on 4 July 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
Absolutely a fine article, John. A great deal of the information will aid me in updating the Ph.D. I received in 1968, although I did use Turner and Verhoogan as a textbook in "Igneous and Metamorphic Petrology." I look forward to your next post. BTW, in the next version of the excellent illustration beginningthe article could you show a more obviously continuous and recently uplifted mountain range and label it as such? This would possibly have more significance to incipient geologists and emphasize the importance of exposing newly elevated rock to the weathing (re: rock) cycle.
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David Kirtley at 04:29 AM on 4 July 2013Climate change science: what’s in a name?
Contrarian cries that us alarmists are trying to change "global warming" to a new name in 1, 2, 3...
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BillEverett at 03:34 AM on 4 July 2013Climate change science: what’s in a name?
"To the public it can appear that there is less warming, because the rate of temperature increase at the Earth’s surface has slowed down in the last decade."
According to the World Meteorolgical Organization, "The decadal rate of increase in the global temperature accelerated between 1971 and 2010. The global temperature increased at an average estimated rate of 0.17°C per decade during that period, compared with 0.062°C per decade for the entire 1880-2010 period. The average 2001-2010 decadal temperature was 0.21°C warmer than 1991–2000, which in turn was +0.14°C warmer than 1981-1990."
Moderator Response:Sure, but sceptics look at short term data, preferably picking a really hot outlier like 1998 as the baseline. The Escalator shows the how the trick works...but anyway:
"The planet has continued to accumulate heat since 1998 - global warming is still happening. Nevertheless, surface temperatures show much internal variability due to heat exchange between the ocean and atmosphere. 1998 was an unusually hot year due to a strong El Nino."
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