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Abrupt climate change

One part of a recent survey caught my attention:

The strongest correlate of opinion on climate change is partisan affiliation. Two-thirds of Republicans (67%) say either that the Earth is getting warmer mostly because of natural changes in the atmosphere (43%) or that there is no solid evidence the Earth is getting warmer (24%). By contrast, most Democrats (64%) say the Earth is getting warmer mostly because of human activity. … The divide is even larger when party and ideology are both taken into consideration. Just 21% of conservative Republicans say the Earth is warming due to human activity, compared with nearly three-quarters (74%) of liberal Democrats. [Pew Research Center] (Skip to videos, data, index.)

In other words, most of the general public appears to believe that the existence of abrupt climate change A large-scale change in the climate system that takes place over a few decades or less, persists (or is anticipated to persist) for at least a few decades, and causes substantial disruptions in human and natural systems. (formerly known as anthropogenic ‘Human-caused’ global warming) is a question of politics rather than science. They’re not looking at evidence published in peer-reviewed science journals before adopting a position. Instead, they seem to decide that their political party’s position on climate change is “X,” so they believe “X.” Finally, this explains why some people who watch a documentary that exaggerates the science end up imitating that smug politician’s You have to realize that I view ‘politician’ as a VERY dirty word in order to get the full effect of this sentence. alarmism. I run into hordes of them on campus, and I always rebuff their attempts to guilt me out of driving by saying “Why worry about the Earth when we’ve got 7 planets R.I.P. Pluto, 1930-2006 to spare?!

Keep in mind that I’m only saying the existence of abrupt climate change is a purely scientific question. I realize that our response to climate change is a legitimate political question. But let’s set that question aside to contemplate the existence of abrupt climate change. Instead of lining up behind politicians, let’s take the road less traveled by examining some evidence given to us by modern science.

To begin with, it’s indisputable that the Earth’s climate has varied wildly in the past. Vostok ice core data confirm that for nearly half a million years, the climate has changed cyclically. In all that time, the maximum CO2 concentration never went above 300 ppm parts per million . It’s hit higher levels millions of years ago, but usually Heinrich and Dansgaard-Oeschger events (among other examples of natural abrupt climate change) show that the natural climate is only fairly stable in the long run. These events show that the climate can quickly move from one stable “attractor” to another. I should stress, however, that results like Meehl 2004 show that today’s changes aren’t natural. in gradual ways. Plus, the Earth was essentially a different planet back then, with a different biosphere basking under the light of a very slightly The Sun was only barely fainter tens of millions of years ago, but high CO2 concentrations hundreds of millions of years ago or more were partially compensated for by the lower solar luminosity. Also, the continents shift on these timescales which affects the climate too. dimmer Sun so comparisons across that much time are tricky at best.

Vostok ice core data

Natural variations are evident in the data, of course. The most prominent cycles over geological time are governed by (among other effects) Milankovitch cycles which are caused by periodic variations in the Earth’s orbit.

Bizarrely, the CO2 concentration is at 380 ppm parts per million today. That’s ~26% higher than it’s been in the last half million years. Notice that the current CO2 concentration is off the scale of the Vostok data graph. If this is due to natural variability alone, it’s quite a coincidence that it’s happening right after we started burning enough oil to fuel ~800 million cars, and burning coal by the gigaton to supply ~50% of our electricity.

Furthermore, it seems like the CO2 at Vostok typically increased centuries after the temperature started to increase. (Ice core data are difficult to analyze in this manner, though.) At least, that’s the way it used to work. Right now, the CO2 concentration is at an unprecedented level but the temperature is barely above normal. Again, this implies that we’re not experiencing natural climate variability because what’s happening today doesn’t match the behavior of the ancient climate.

According to physics that was firmly established decades before I was born, CO2 warms the planet by absorbing infrared radiation from the ground better than it absorbs visible radiation from the Sun. So this rapidly increasing CO2 should cause a rapid temperature increase:

Multiple independent temperature reconstructions over the past 1000 years

The above graphs are quite busy, so here’s an overview of each one:

  1. The top graph shows temperatures over the last 300 years, as recorded by instruments. Notice that several independent instruments are telling us that the temperature has increased dramatically in recent decades.
  2. The middle graph shows temperatures over the last 1000 years as reconstructed from various proxies such as ice cores, tree rings, boreholes, glacier retreat, etc. The different curves are based on different data and algorithms, and were derived by scientists from all over the world. Note that all of them show an abrupt temperature increase in the last few decades. See Table 6.1 for more details.
  3. The bottom graph shows a “most likely” temperature reconstruction over the last 1000 years. This estimate uses all the previous curves, weighted according to their statistical uncertainties. The shading represents the combined uncertainty; darker areas are more confidently known.

Perhaps this is a coincidence? All the evidence I’ve described so far just shows that CO2 and temperatures have both risen in an apparently artificial manner in the last few decades. But Meehl 2004 tested whether or not recent temperature observations could be explained by natural variations alone:

Meehl 2004 shows recent temperatures are caused by CO2

The black curve represents observations. The blue curve represents the result of a computer simulation that accounts for natural variations like volcanic eruptions and changes in the brightness of the Sun. The shaded blue area represents the uncertainty of that simulation. The red curve includes all the natural variations in the blue curve, but adds human emissions like CO2 and sulfate aerosols. Notice that after ~1970 the observed temperatures aren’t consistent with natural variations, but they are within the error bars of the prediction made by accounting for human emissions.

The Earth is so massive and ancient that we tend to instinctively believe ‘Don’t treat C02 as a pollutant’ in the Christian Science Monitor by Mark W. Hendrickson on June 23, 2009 wrongly says “And how do you propose to regulate Earth’s temperature when as much as three-quarters of the variability is due to variations in solar activity, with the remaining one-quarter due to changes in Earth’s orbit, axis, and albedo (reflectivity)? This truly is ‘mission impossible.’ Mankind can no more regulate Earth’s temperature than it can the tides. … 1. Human activity accounts for less than 4 percent of global CO2 emissions. 2. CO2 itself accounts for only 10 or 20 percent of the greenhouse effect. This discloses the capricious nature of the EPA’s decision to classify CO2 as a pollutant, for if CO2 is a pollutant because it is a greenhouse gas, then the most common greenhouse gas of all – water vapor, which accounts for more than three-quarters of the atmosphere’s greenhouse effect – should be regulated, too. The EPA isn’t going after water vapor, of course, because then everyone would realize how absurd climate-control regulation really is.” that humans aren’t powerful enough to affect the climate on this scale. For example, those awe-inspiring volcanic eruptions simply must dwarf anything we do, right? Surprisingly, humans emit ~100x more CO2 than volcanoes.

Even still, the Earth is a stable system, right? Won’t our changes to the atmosphere just provoke a natural response that cancels them out, preventing us from significantly altering the climate? Well… maybe. The natural climate certainly did appear fairly Heinrich and Dansgaard-Oeschger events (among other examples of natural abrupt climate change) show that the natural climate is only fairly stable in the long run. These events show that the climate can quickly move from one stable “attractor” to another. I should stress, however, that results like Meehl 2004 show that today’s changes aren’t natural. stable in our absence. However, a number of positive feedback effects present the disturbing possibility that the climate is only metastable:

  • Melting Arctic sea ice uncovers darker ocean water, so more heat is absorbed after the ice starts to melt, which speeds up the remaining melting…
  • Warmer oceans will evaporate more water vapor into the atmosphere, which is a more effective greenhouse gas than CO2.
  • Warmer deep ocean temperatures may destabilize methane hydrate deposits, releasing another more potent greenhouse gas.
  • Melting permafrost releases CO2 and methane.
  • Melting glaciers help to lubricate the slide of the glacier into the ocean, speeding up the loss of glaciers once the process starts.
  • Higher temperatures increase the risk of forest fires, which release CO2.
  • The dust caused by vegetation loss due to shifting precipitation patterns, fires and even other pollutants darkens snow, causing it to melt earlier.

There are also negative feedback effects, such as the fact that trees grow faster in higher CO2 and thus store carbon in their wood faster. [Update Thanks to Dr. Geoffrey A. Landis for his additions and corrections to this section and the faint young Sun caveat. by Dr. Landis: Also, the Stefan-Boltzmann equation says that hotter objects radiate more, and higher temperatures = more evaporation = more clouds = higher albedo.] But I worry that the abrupt spike in CO2 levels might cause positive feedback effects to dominate– at least temporarily. In other words, it seems likely that a little bit of warming will lead to more warming.

Bottom line: As far as I can tell there’s a mountain of scientific evidence showing that abrupt climate change A large-scale change in the climate system that takes place over a few decades or less, persists (or is anticipated to persist) for at least a few decades, and causes substantial disruptions in human and natural systems. is a matter of serious concern.

On a completely different note, as an ordinary American I think we should do something about this matter. We’re still the most To my foreign colleagues and friends: You wanna fight about it? :) technologically advanced nation in the world, with one of the largest, best educated workforces in history. Our economy is very capitalistic, which makes us highly adaptable compared to more socialist countries that are mired in bureaucracy. If any country can solve this problem, it’s us.

The legislation currently in the Senate needs to be passed. This bill has already been weakened in the House and it’s only the first step, but it’s the least we can do to convince the world that the United States is ready to lead once again.

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Update: Here are some related videos:

  • The GRACE satellites observe ice mass loss in Greenland and West Antarctica, and observe global water storage.
  • Here’s a brief history of CO2, and a NOAA animation of daily CO2 concentrations during 2008.
  • This interactive graph and this short video compare emissions from different countries over the last few centuries.
  • This animation shows the importance of looking at long-term climate trends rather than short-term weather noise.
  • Dr. Marshall Shepherd promotes climate literacy and slays zombie theories.
  • David Attenborough has a short conversation with Peter Cox about how scientists attribute the recent global temperature rise to human activities.
  • National Geographic asks “Could just 1°C change the world?” What about 2°C, 3°C, 4°C, 5°C, or 6°C?
  • Greg Craven made a short video about risk management.
  • A 10 minute video summarizes the end-Permian extinction; a longer version goes into more detail.
  • A 5 minute video introduces ocean acidification.
  • Earth: The Operators’ Manual tells the story of Earth’s climate history and our relationship with fossil fuels. Here are short clips of Richard Alley discussing ice core climate records, and explaining that clean energy costs about as much as modern plumbing.
  • The UK forum on “Climate Change: Values, National Security, and Free Enterprise” featured Dr. Katharine Hayhoe, Brig. Gen. (Ret.) Steve Anderson and Republican Bob Inglis.
  • David Archer made a series of video lectures called Global Warming: Understanding the Forecast.
  • Naomi Oreskes talks briefly about the implications of climate change, and gives a longer presentation based on Merchants of Doubt.
  • A series of short videos examines claims made by Anthony Watts regarding his surfacestations.org project, and the Oregon “Petition Project”.
  • An episode of Horizon called “Science Under Attack” discusses “climategate” and climate change contrarians.
  • A BBC special called “Meet the Climate Sceptics” examines some of Lord Christopher Monckton’s many claims. Peter Sinclair also did this, as well as John Abraham and Peter Hadfield (followup).
  • Barry Bickmore gives a talk about his own former skepticism.
  • Stephen Schneider faced 52 “climate sceptics” in an episode of Insight called The Sceptics (also available at YouTube). He also gave a more technical lecture and discussed the boundary between politics and science.
  • Richard Alley gave a technical 2009 presentation called “The Biggest Control Knob: Carbon Dioxide in Earth’s Climate History.”
  • Jerry Mitrovica gave a technical 2011 presentation regarding accelerating sea level rise.
  • Here are videos from the 2012 AGU and other AGU videos.
  • Bob Watson gave a technical 2012 presentation summarizing climate change.
  • Ray Pierrehumbert gave a technical 2012 presentation summarizing successful predictions in climate science.
  • Richard Alley gave a technical 2013 presentation called “Slip Slidin’ Away – Ice sheets and sea level in a warming world.”
  • Jennifer Francis gave a technical 2013 presentation called “Climate Change and Extreme Weather.” Here’s a related 2 minute video.
  • Andrew Dickson gave a technical 2009 presentation called “Acidic Oceans: Why Should We Care?”
  • A series of panels at the 2011 AGU discussed declining reef health and tipping points.
  • Ken Caldeira gave a technical 2012 presentation called “Ocean Acidification: Adaptive Challenge or Extinction Threat?”

Further reading:

  • Global climate models have made many successful predictions.
  • In 2005, 11 national science academies urged world leaders to “acknowledge that the threat of climate change is clear and increasing.”
  • In 2009, 13 national science academies told world leaders that “the need for urgent action to address climate change is now indisputable.”
  • Climate change statements from world religions and Young Evangelicals.
  • NASA tracks vital signs of the planet at JPL’s Global Climate Change website. Don’t miss interactives like Eyes on the Earth.
  • Skeptical Science has a wide variety of informative articles with versions ranging from “basic” to “advanced”.
  • Real Climate is climate science from climate scientists. It’s an excellent resource for readers who understand Skeptical Science’s “advanced” articles and want more.
  • Tamino is a professional statistician whose blog Open Mind tirelessly debunks contrarian arguments. Some old articles can be found here.
  • Science of Doom evaluates and explains climate science in a lucid but very technical manner.
  • The equilibrium climate sensitivity to doubled CO2 can be determined in many different ways. For instance, here’s a figure from Royer et al. 2007 (PDF) which concludes that “a climate sensitivity greater than 1.5°C has probably been a robust feature of the Earth’s climate system over the past 420 million years”.
  • Global Climate Change Impacts in the United States (2009) summarizes the science and the impacts of climate change on the United States, now and in the future. This NAS report (2012) examines sea level rise off the U.S. west coast. Sea level rise varies regionally due to factors like the gravity of thinning ice sheets.
  • The American Institute of Physics describes the discovery of global warming, including the carbon dioxide greenhouse effect.
  • The IPCC’s 2007 report (PDFs) on the physical science basis of climate change reviews the scientific literature and provides a summary for policymakers (PDF). Previous reports: 1990, 1995, and 2001.
  • The Copenhagen Diagnosis summarizes some of the science published since the IPCC’s 2007 report. Here’s their list of figures.

Links to climate data and source code:

  • NOAA’s climate indicators and climate at a glance calculates trends for many different climate variables, as does WoodForTrees. The Skeptical Science trend calculator also estimates statistical significance.
  • Here are maps of global temperature from NASA and New Scientist, and U.S. temperature trends in each state.
  • Here are sea level rise data, NOAA’s coastal flooding impacts viewer, and informal interactive maps of global (caveats) and American coastlines.
  • These interactive models explore the spectrum of CO2, the carbon cycle, climate models, and much more.
  • Here’s an interactive simple climate model.
  • The Javascript Ice Sheet Model is interactive and open-source.
  • caerbannog666’s global temperature virtual machine runs in VirtualBox; here’s the documentation.
  • JPL archives NASA’s climate and ocean data at PO.DAAC, which features the State of the Ocean.
  • Temperature proxy data and various instrumental temperature records can be downloaded here.
  • The code for past temperature reconstructions can be downloaded here.
  • The Ice Sheet System Model is open-source software from NASA’s Jet Propulsion Laboratory, California Institute of Technology.
  • Climate models from the IPCC 2007 report can be downloaded here and here. Newer RCP scenario data are here. The model outputs are available here.
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I’ve been discussing abrupt climate change A large-scale change in the climate system that takes place over a few decades or less, persists (or is anticipated to persist) for at least a few decades, and causes substantial disruptions in human and natural systems. on the internet for several years, mostly at Slashdot under the pseudonym khayman80. The interesting bits of these conversations have been copied here, but please note that my statements have been edited Each comment is linked back to the original location in the Slashdot archives so you can compare the current version to the original. Those links look like: [Dumb Scientist] or [Jane Q. Public] and expanded since I first wrote them. Here’s an index with links to each conversation:

  1. People wonder why “climate change” replaced “global warming.”

  2. Rrvau asks if scientists predicted an ice age in the 1970s.

  3. People inquire about the scale and impact of human CO2 emissions.

  4. An Onerous Coward asks about nuclear and solar power.

  5. Stormcrow309 asks about potential flaws in the Vostok ice core analysis.

  6. M4cph1sto doubts that temperatures are increasing.

  7. Jane Q. Public asks if sunspot activity causes global warming, among many other topics:

    1. The importance of peer review.
    2. “Cosmic rays are responsible for global warming.”
    3. “Water vapor is a stronger greenhouse gas than CO2.”
    4. The accuracy of the “hockeystick” graph.
    5. What does the IPCC say about hurricanes?
    6. “CO2 increases after temperature, so it doesn’t warm the planet.”
    7. “CO2 is already saturated, so adding more CO2 isn’t going to warm the planet any more.”
    8. “It’s not that simple.”
    9. We agree that the media over-hypes disaster scenarios.
    10. The Salem Hypothesis and the application of a modified version to this debate.
    11. “The troposphere isn’t warming enough, so greenhouse warming theories are fundamentally flawed.”
    12. Jane says her comments have been taken out of context and deliberately portrayed in a negative light. So please compare her statements to the originals at Slashdot, which can be accessed through links that look like [Jane Q. Public]
      Update: Jane’s index continues here.
  8. Kyle asks about the political and economic implications of climate change. Also, he asks if global temperatures are only appearing to increase due to urban expansion.

  9. Jim P.E. asks if the President is receiving sound advice.

  10. Bopeth asks about our population growth, and economic issues associated with climate change.

  11. Anonymous says that my “comments exhibit the most profound and disturbing kind of scientific elitism,” along with:

    1. “How do you wager on whether climate change is anthropogenic or not?”
    2. I criticize peer review.
    3. “What I want to see next is the contrary case from a well-versed expert who has reached conclusions that conflict with yours.”
    4. Why shouldn’t we look to politicians for scientific answers?
    5. “What, exactly, would you like to see from the general public in terms of reasoning about this subject?”
    6. Marbs asks “What opinion do you currently hold that contradicts the mainstream scientific community?”
    7. Why do high tides happen on opposite sides of the Earth at the same time?
    8. “… we can’t do ‘parallel earth’ experiments to test various parameters … and nobody has a track record of ‘getting it right’ long term because there hasn’t been a long term yet.”
    9. Marbs asks about the graph on Steven Fielding’s website and the “due diligence report.”
  12. Spector asks how climatologists attribute the recent warming to human activity.

  13. Reivan asks about thermodynamic equilibrium.

  14. Gkai says “… newest global data are not so supportive of the idea that man-produced CO2 is responsible for the bulk of global warming” then claims that no climate model takes clouds or changes in the Earth’s albedo into account, and says my article is not convincing because of model validations.

  15. Thethibbs doesn’t want to quarrel with my “religion” so he rebuts the evidence I’ve presented with a link to an article by Marc Morano.

  16. Elkto doesn’t believe CO2 is causing any problems because “Earth cooled a degree last year, satellite images show arctic ice cap growing the last three years, lack of sunspots is pointing to a scary minimum, the CO2 increase contributes to less than 1/2 of a percent increase in greenhouse gases (do not exclude the largest greenhouse gas, water vapor.)”

  17. Shivetya says “natural CO2 production is 20x man’s … but it damn well won’t stop the “consensus” train.”

  18. Techno-vampire says I’m leaving out significant information about the Little Ice Age, and the Medieval Warm Period, which he implies was a global event.

  19. Someone implies that I’m a semi-honest “scientist” because I’m referring to ice core records that “only” extend 650,000 years into the past. Also:

    1. “Tacking high resolution data from modern thermometers on to data taken from ice cores seems dubious.”
    2. “Be careful about weeding out data just because it doesn’t support your hypothesis. … You seem quite certain that there is only one way to explain things. You’ve already assumed your hypothesis is true. It’s not good science, and I think you should be more skeptical.”
  20. Avysk claims that I’m a lying idiot who perverts things deliberately because I pointed out that the current CO2 concentration of 380ppm is ~26% above the 650,000 year maximum of 300ppm.

  21. Fluffy99 says that scientists assume that the Earth’s temperature is supposed to be constant, leading them to ignore solar variations which Fluffy99 claims are responsible for global warming. He claims human emissions aren’t the dominant climate forcing, and it’s possible we’re having no effect at all. Later, he implies that scientists reach conclusions that are motivated by funding.

  22. Someone says “How come global-warmists never mention water vapor, which is by far the biggest greenhouse gas. I guess there isn’t any money in selling “steam credits”.”

  23. Flyingrobots says “The main problem I have with your position is the incessant manipulation of temperature data by those who really believe in global warming.”

    1. Flyingrobots uses the Galileo Gambit, cites Claude Allegre as a creditable person who argues against my point of view, and says “I’m not claiming giant conspiracies amongst scientists, however, I think the author [Stephen Goddard] raises some valid points that require further explanation.”
    2. Flyingrobots repeats: “Folks like Monsieur Allegre raise valid points that should be addressed and not swept under the carpet.”
  24. Jmerlin claims that “man-made climate problems (even if they are true – though largely unproven)” haven’t caused anything “bad” to happen, and won’t cause anything “bad” to happen until our children’s great great grandchildren are dead, and possibly not for hundreds of thousands of years. So if politicians want to use a “destructive” tax to “punish” him for using coal and oil, he thinks they should be worried about angering citizens like him, because “it’ll be the French Revolution all over again, and I’ll bring my guillotine with me.”

  25. Ivan256 claims that the Vostok ice core graph I included is horrendously misleading because, apparently, I was fooled into thinking the data suggest that increased atmospheric CO2 leads to higher temperatures.

  26. Disco inferno criticizes nuclear power.

  27. Tmosley claims to be a scientist who wonders how any temperature increase can be proven to be anthropogenic when we don’t have a control [Earth], seems to think heat capacities of water vapor and CO2 are the basis of the greenhouse effect, then implies that environmental legislation would murder people and “cut off the arms and legs of our civilization with an environmentally friendly electric chainsaw”.

  28. SmilingSalmon thinks that McIntyre and McKitrick have uncovered a weakness in the scientific process when they tried to publish a comment implying that the “hockey stick” algorithm of MBH98 was tuned to produce a hockey stick from any input, even “red noise”.

  29. Budenny claims that the climate could exhibit negative feedback, wonders if the climate is warming faster or differently than ever before, and accuses the climate science community of refusing to release their data.

  30. The AGU Fall Meeting is the largest geophysics conference in the world. Most attendees are mainstream scientists, but occasionally one runs into a climate change contrarian:

    1. At the 2008 AGU Fall Meeting, I found a poster by Maruyama et al. which claimed that most of the warming over the last 50 years is caused by natural oscillations, and that we should expect 0.5K of global cooling by 2020.
    2. I met Norman Rogers at the 2009 AGU Fall Meeting next to his poster called “Inconsistencies and Fallacies: IPCC 20th Century Simulations, Multi-Model Ensembles and Climate Sensitivity”.
    3. At the 2010 AGU Fall Meeting, I saw Norman Rogers again at his poster titled “Why do anthropogenic global warming skeptics have poorer scientific credentials than their opponents?”
    4. I met D.C. Smith at the 2010 AGU Fall Meeting in front of his poster titled “Line by Line Analysis of Carbon Dioxide Absorption for Predicting Global Warming” which claimed that doubling CO2 would only result in 0.26C warming (at most).
    5. Norman Rogers of the Heartland Institute (H.I.) and David Smith present contrarian posters at the 2012 AGU Fall Meeting.
    6. Norman Rogers (H.I.) et al. praise Lomborg, imply scientists want to kill off most of humanity.
  31. Radtea says “Global atmospheric heat content is meaningful. Global mean temperature is not.”

    1. Radtea says “I don’t agree with your characterization of heat as strictly a type of energy transfer. … I still don’t understand what anyone thinks they are doing with global average temperature, but whatever it is, it isn’t physics.”
    2. Radtea says “… you’re not a computational physicist, or you would have noticed the lack of energy conservation in some models (it is added by hand as a correction on each time step) or unphysical boundary conditions in others (ocean surface in particular).”
    3. Radtea asks “… what data would make you change your beliefs regarding global warming/climate change?”
    4. Radtea says “isn’t it curious that there’s no evidence of warming in the past 15 years but we keep on hearing about how Arctic ice is melting at record rates.”
    5. Radtea says “your claim that most of the models used in climate research are true to first principles is false. I am a computational physicist, and every GCM I have looked at has non-physical aspects that violate well-established physical principles, most worriesomely conservation of energy.”
  32. Beryllium Sphere correctly notes that “Qualitatively, what you’d expect from climate change is more precipitation (because there’s more evaporation) and therefore thickening at high elevations where the snow stays cold, while lower warmer regions flow faster or even melt”, then someone who tends towards quantum physics briefly challenges that idea.

  33. Hadlock helpfully corrects my terminology regarding glacier melt/flow/thinning.

    1. Jbengt and HiThere make genuinely helpful comments about glacier thinning.
    2. At the 2009 AGU fall meeting, I met a glaciologist next to her poster about glacier feedback effects.
    3. At the 2010 UNAVCO conference, Meredith Nettles showed that glacial earthquakes in Greenland have dramatically increased in frequency recently, Steve Nerem showed that Helheim glacier in Greenland is accelerating based on GPS, imaging and InSAR, and Tim Dixon showed correlations with independent estimates that subtract calving/meltwater flux from snowfall accumulation.
  34. In response to a study showing “surprising, extensive thinning in Antarctica, affecting the ice sheet far inland,” Jarek asks “Does it? The increased temperatures of west Antarctica are more than compensated by decreased temperatures elsewhere in Antarctica.”

    1. Jarek says “We are literally being served half truths. Or is less than half truths. Most of Antarctica gets colder, some of it gets warmer. By reporting on the parts that get warmer, media tries to sell disasters just because it sells better than the whole truth and nothing but the truth.”
    2. Troed claims that “Antarctica as a whole isn’t warming unless you deal in dubious statistical models.”
  35. Whatanut wonders if it will be cheaper to adapt to climate change rather than trying to avoid it by reducing CO2 emissions.

  36. Msevior says “One of the catastrophic outcomes of climate change are large sea level rises due to ice melt in the polar regions. Presumably there are models that predict how this could occur with global warming. So the question is, do these data agree with these models?”

  37. Smoker2 says “… there is actually more minimum ice cover than last year, and last year had more cover than the year before. Why do they [NASA] not mention this at all ? Maybe the point is to mislead?”

  38. After repeating several common contrarian talking points, Tontoman links to a speech by Michael Crichton where “he criticises the papers done by IPCC and debunks other global warning myths.”

    1. JLF65 suggests that I’m discounting Crichton merely because he’s a science fiction author whose opinion goes against mine.
    2. Tontoman says “If you think we should discount Crichton, then perhaps we should debunk the ‘global warming’ movement because one of its leaders, Al Gore, also is a politician whose highest degree is Bachelor of Arts in Government.”
  39. Research into the effects of cosmic ray intensity on tree growth rates sparks an interesting discussion.

  40. A friend brings up the “climategate” hacking story.

    1. I mention that working group 2 of the IPCC made some embarrassing mistakes, and I find some errors in the IPCC AR4 WG1 report.
  41. Jerry McGowan claims that “it’s right that CO2 is already saturated and more CO2 won’t warm the planet anymore.”

    1. Joshua claims “add CO2 and the humidity is reduced. Net change to greenhouse effect = 0 = saturation.”
  42. DTJohnson claims “There are no mountains of research that show why any climate change is happening or even IF climate change is happening.”

    1. DTJohnson lectures me about seasons, and is “struck by how little I seem to understand about the basic physics of gases… which is, after all, what we’re talking about.”
  43. Phantomfive claims that “there is no really good scientific evidence of a threat from CO2 …”

    1. Omb criticizes a paper I linked, saying things like “This paper is evidence of one thing only, that the mesh used in the (DOE) PCM is far too course”.
    2. I agree with phantomfive that sea level rise during the 21st century will be less than 20 meters, but point out that even a ~1.2 meter sea level rise by 2100 will bring substantial hardships, along with problems caused by changes in precipitation patterns.
    3. Phantomfive tells me not to go insane over “scenarios like this that have no scientific backing.”
    4. Phantomfive claims that “temperatures have not continued to rise as those models predicted would happen.”
    5. Phantomfive says that my argument is “about the weakest line of logic ever.”
    6. Regarding projected climate changes, phantomfive asks “In the worst case, will it be worse than the dustbowl?”
    7. Phantomfive claims that “the warming seen over the last few decades is entirely attributable to the reduction in aerosols in recent years. This is mentioned in WGI chapter 2 of the IPCC report.”
    8. Phantomfive notes that President Bush did eventually listen to climate scientists.
  44. I lament the fact that NASA’s mission is no longer to “understand and protect our home planet”.

  45. “Yes, sounds like someone didn’t read What Every Computer Scientist Should Know About Floating-Point Arithmetic.”

  46. “I’m finishing a program that inverts GRACE data to reveal fluctuations in gravity such as those caused by melting/thinning glaciers.”

    1. I’d previously compared GRACE to GOCE.
  47. Khallow says “there’s a pile of articles from Dr. McIntyre. Many of these criticize HadCRUT3 or its components. So yes, the data itself has been called into question repeatedly.”

    1. Khallow: “Fraud may well be occurring.”
    2. I show Khallow where to download climate data and source code.
    3. Khallow goes Sky Dragon Slayer: “Jane Q. Public won… Fuck you, khayman80.”
  48. Thirdeye asks “do you know how much pollution is discharged into the atmosphere when a single volcanic eruption occurs? Wondering how it compares to the anthropogenic discharge?”

    1. Thirdeye asks “aren’t there some schools of thought that think that increased CO2 in the atmosphere may actually contribute to a cooler Earth by increasing the Earth’s albedo?”
    2. “Also, is there any nuclear activity going on in the core that could be warming the planet?”
  49. JordanL says “One of the things that REALLY bugs me about climate research is seeing LEGITIMATE scientists use the word “SKEPTIC” as a SMEAR.”

    1. Daniel Dvorkin points out that “when you have a bunch of people spouting pseudoscientific garbage who are handed the ‘skeptic’ label as a gift, it’s inevitable that those who point out the garbage will appear to be ‘smearing skeptics.'”
  50. I say “I’ve never heard of Lomborg before today, but your summary makes him sound like someone I could agree with. That’s mainly because I think most of the ‘green’ movement is irrational, and one manifestation is that they’ve blocked the advancement of nuclear power for decades.”

  51. I say “Cool, that’s an awesome website! I especially liked the graphic here. I think the ‘Phil current’ curve describes me well. I agree with Phil that the IPCC’s error bars seem a little narrow, but not by much.”

  52. Timmarhy says “I’ve never seen any overlap between creationists and AGW skeptics. I demand you show me some evidence of this.”

  53. BonquiquiShiquavius says to climate scientists: “publishing a single report that wildly contradict previous findings makes it practically impossible to defend you.”

  54. Amouth claims that extracting tidal power would slow/stop/reverse the Moon’s ascent from Earth.

    1. Prof. Pete Bender adds some insights regarding tidal dissipation.
  55. ShakaUVM and I have an extended discussion about many topics.

  56. I’ve been toying with the idea that loggers can fix the CO2 problem. Send them out to harvest pine trees at the end of their fast-growing (and thus fast-CO2-absorbing) phase.”

  57. Arc86 and I discuss various surveys of the scientific community regarding climate change.

  58. The Hatchet has “been debating global warming for a damn long time, and NOBODY has ever had a damn thing to say about the real global heat content (including oceans) …”

  59. Reythia ran across a new, more accurate term: ‘climate destabilization’.

  60. Stella says “Unless we stop procreating mindlessly and start to deindustrialise the society there



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