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McCloud at 05:17 AM on 6 July 2010We're heading into an ice age
Question: In the projections shown in Figure 4, it looks like there is an upper limit of about 4 degrees C for the temperature anomaly, even at 5000 Gigatonnes CO2 emission, and only about 2 degrees for 1000 Gton. However, the graph in Figure 2 shows that the temperature anomaly is projected to reach 4 degrees C in just under 100 years, on a more or less exponential path, with no sign of slowing down. Is there or is there not an upper limit to the temperature anomaly given these assumptions about the magnitude of CO2 emissions? How sure can we be that the projections shown are correct, given the chaotic nature of the planet's climate? Question 2: Can climate change result in positive feedback as ocean warming leads to the release of more CO2? -
Rob Honeycutt at 05:15 AM on 6 July 2010Archibald’s take on world temperatures
GISS link messed up... GISS -
Rob Honeycutt at 05:12 AM on 6 July 2010Archibald’s take on world temperatures
Roy Latham... I'm not sure where you get "no global warming trend in the past 15 years." The data don't seem to support you in this statement. UAH GISS RSS -
Peter Hogarth at 05:01 AM on 6 July 2010CO2 was higher in the late Ordovician
Tom_the_Bomb at 04:22 AM on 6 July, 2010 The evidence partly comes from analysis of similar stars to our sun at different stages in their life cycle and well tested physics based models. Stars of a certain mass profile appear to display similar growth and fusion burn and brightness patterns, many have star spot cycle activity similar to our sun. I'll dig out some references.Response: How the sun was cooler and how this affects climate is discussed in more detail at CO2 was higher in the past. -
Roy Latham at 04:35 AM on 6 July 2010Archibald’s take on world temperatures
Archibald seems to be in error on two accounts: North America does not equate to the world and snow pack is a consequence of precipitation amounts as well as the temperature. For example, there is a global warming trend, but there has not been an observed warming trend in the United States in recent decades. Of course, there has not been a global warming trend for the past 15 years. The surface ice in the Arctic melts roughly every 70 years, with the last melt in the 30s, and the one before that around 1880. National Georgraphic Magazine about a year ago had an article that described the oscillation. When sea ice decreases in the Arctic it increases in Antarctic, and that has happened this time as well. Sea ice depends upon the relative warmth ocean currents. As to the ice caps, the last IPCC report claimed that the total land ice is very close to stable. If temperatures are well below zero, warming does not cause melting. In the climate debate, the burden of proof is for advocates to prove that there is a climate crisis. The crisis theory is based entirely upon math models that predict the earth will warm considerably more than the straight physics of carbon dioxide predicts. The test of math models is whether they work reliably. Observed data is below the model error bounds, so the models are wrong. The present task therefore ought to be to find models that work. -
Andrew Xnn at 04:23 AM on 6 July 2010Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
Peter; Thanks for the additional clarification. Apparently, I became confused with the following sentence: “Indeed year on year variations in wind speed correlate well with ice extent changes Ogi 2010b, but what about the longer term?” Understand now that this is in reference to seasonal variations. However, the overall decrease in wind speed with increasing storm activity doesn’t make a lot of sense. Understand that downwelling longwave radiation follows cloud cover. However, the shift in sea ice extent is seasonal and the change In cloud cover appears inconsistent with ice observations. That is the greatest negative ice anomaly over the last 3 years has tended to be in September, while cloud coverage in Summer/Fall is small. So, why are we seeing the largest anomalies right around sunset? My guess is that this is when thicker ice is more prominent as a fraction of the total basin. Perhaps in contrast, during the winter max, thinner ice is a misleading observation. -
Tom_the_Bomb at 04:22 AM on 6 July 2010CO2 was higher in the late Ordovician
John, what happened to "the sun being cooler" in this argument? You mention it in the summary box but nowhere at all in the body of the text; instead the argument drifts off into rising and falling CO2 levels, that frankly I'm having a hard time understanding. Where is the evidence for the sun being cooler? -
Gillespie at 04:10 AM on 6 July 2010Temp record is unreliable
There are quite a few reasons to believe that the surface temperature record – which shows a warming of approximately 0.6°-0.8°C over the last century (depending on precisely how the warming trend is defined) – is essentially uncontaminated by the effects of urban growth and the Urban Heat Island (UHI) effect. These include that the land, borehole and marine records substantially agree; and the fact that there is little difference between the long-term (1880 to 1998) rural (0.70°C/century) and full set of station temperature trends (actually less at 0.65°C/century). This and other information lead the IPCC to conclude that the UHI effect makes at most a contribution of 0.05°C to the warming observed over the past century. http://www.globalwarmingsurvivalcenter.com -
Peter Hogarth at 03:19 AM on 6 July 2010Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
Andrew Xnn at 01:59 AM on 6 July, 2010 Just to be clear, if ice is thinner or weaker, there is a higher probability of wind causing movement and break up as Arctic ice is floating and potentially mobile. Wind can accelerate loss in melt season when long term warming is driving a long term ice thinning trend. Wind contributed to major ice minimum in 2007, but ice had already thinned significantly. Wind is most likely not the primary driver of ice cover loss, - would you think it probable that wind is a major contributor to permafrost melt, Arctic Ice shelf loss, glacier retreat, or a lengthening melt season? The common factor is mean temperature. Anomalous high winds, (from whatever direction) in the recent past have not meant 2007 like losses, just higher deviation away from the ongoing downward trend. Similarly winds played a role in early 2010 anomalous rapid localised increase in peripheral ice extent. You also missed why cloud cover matters. -
Peter Hogarth at 02:22 AM on 6 July 2010Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
Andrew Xnn at 01:59 AM on 6 July, 2010 No, you have misread (accidentaly I am sure). Wind speed variations do correlate with ice extent variations, but this is "natural" short term variation within a melt/freeze season. Overall, average wind speed shows a reducing trend, despite increased storm activity. Temperature, both air and water, continues to correlate with ice extent, and most probably ice volume, through both surface and bottom melt. -
Andrew Xnn at 01:59 AM on 6 July 2010Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
Okay; Just to summarize: Winter Ice Extent correlated with Oct/Feb surface air temps. Small changes in Summer and Autumn Cloud Cover 5% Decrease/decade in Winter Cloud cover 5% Increase/decade in Spring Cloud cover Sea Ice correlation with atmospheric oscillations have weakened over time. Only wind speed continues to correlate with Sea Ice extent. Progressively less ice is drifting at faster speeds Progressive increase of Inflow of warmer ocean waters from the south. Many thanks for the great post!!! -
Peter Hogarth at 01:38 AM on 6 July 2010Astronomical cycles
Ken Lambert at 00:44 AM on 6 July, 2010 For the last time, in the case of trends 9 years is relatively short, trend error is obviously higher than that for 18 years, 7 years is even shorter, trend error higher still, 2 years is shorter still and trend error extremely high, no matter if the individual points are just as "accurate" as any other points. All of the altimeters work on basic (obviously I simplify) absolute two way travel time of radar signals. In terms of data from which to derive an overall trend even a handful of points from a new altimeter adds to the picture from other altimeters, (and yes there are known errors in some of the series) but we have to take all of the points to develop the most meaningful trend. Your continued refusal to accept basic principles of statistical analysis discredits you. -
JMurphy at 01:36 AM on 6 July 2010Astronomical cycles
Ken Lambert wrote : Readers might also note the convenience with which you classify time periods as short and long term. 9 years and 7 years are impossibly short term when SLR is down (short term noisy data etc), but when SLR ticks up with Jason 2 over the last 1-2 years - it is 'back on track'. So 7 years data is not long enough for my case, but 1-2 years is 'back on track' and valid for your case. Well, as a reader, I note that I cannot find a quote from chris that states the SLR is 'back on track', but I haven't had a thorough check, so perhaps you could post a link to it to make it easier to find ? I can find, however, this bit from his last post : "There isn’t a huge amount more to be determined from the data Ken. There was a short period (2006-2008ish) where the sea level rise slowed down a bit; the last 18 months or so has seen it return to its trend level. We have to be careful not to attempt to make fundamental interpretations from these instances of short term variability." And that last sentence in particular rather seems to prove you wrong in your assertion. Did you not see that ? What was that about Dunning-Kruger...? -
Ken Lambert at 00:44 AM on 6 July 2010Astronomical cycles
Chris #128 I know the Trenberth papers well Chris, so you would do well not to claim I am 'quite wrong' in quoting information from them. Dr Trenberth's 0.9W/sq.m imbalance includes +0.12W/sq.m Solar contribution from IPCC AR4 Fig 2.4. Are you suggesting that this is minus another 0.15W/sq.m giving a negative Solar forcing for the 2004-2008 period?? This is at variance with Dr Trenberth's figure of 16E20 Joules/year which equals 0.11W/sq.m, already accounted in his Table 1 of subject paper. Dr Trenberth started quoting Von Schukmann to Dr Pielke in April this year. BP produced a demolition of the VS OHC chart showing impossible heat flow rates from the bumps in the curve. See: http://www.skepticalscience.com/Understanding-Trenberths-travesty.html#6839 #BP30. Latest Willis information is that deep ocean heat gain is small; possibly 0.1W/sq.m (on top of the geothermal flux of about 0.1W/sq.m which should always be there). So the VS 0.54W/sq.m of deep ocean gain is most probably wrong - way wrong. Which still leaves us with an imbalance of 30-100E20 Joules/year. Readers might also note the convenience with which you classify time periods as short and long term. 9 years and 7 years are impossibly short term when SLR is down (short term noisy data etc), but when SLR ticks up with Jason 2 over the last 1-2 years - it is 'back on track'. So 7 years data is not long enough for my case, but 1-2 years is 'back on track' and valid for your case. Sit your Dunning-Kruger effect on that unsubtle fact. -
JMurphy at 00:24 AM on 6 July 2010IPCC were wrong about Amazon rainforests
Baa Humbug wrote : Did you find any benefits JMurphy? or is that a silly question? Knowing the source of the 'audit', and also knowing that the IPCC itself would have thoroughly checked everything before publishing, I have to honestly answer 'No' - to the first question, which isn't a silly question at all. Knowing, also, that anything published by humans is subject to human error, I have no problems acknowledging the minor errors found, especially to do with Himalayan glaciers; and the ones found by the recently released Netherlands Environmental Assessment Agency report. Everything else is just semantics and misunderstandings but I'm sure the IPCC will be making doubly sure of their output from now on, which can only be a good thing. I would also not like to be associated with anything associated with NO CONSENSUS, especially as your audit will be used for political, propaganda and denial purposes. You may well have done it with good intentions but you must also have known how it would be used once completed. -
Arkadiusz Semczyszak at 00:13 AM on 6 July 2010Archibald’s take on world temperatures
Archibald, of course, is wrong - we have global warming. It fits perfectly into the process (cycle) of natural changes. Cited work here: Are cold winters in Europe associated with low solar activity? Lockwood et al., 2010.: “The results presented in section allow rejection of the null hypothesis, and hence colder UK winters (relative to the longer-term trend) can therefore be associated with lower open solar flux (and hence with lower solar irradiance and higher cosmic ray flux). A NUMBER OF MECHANISMS ARE POSSIBLE [?! ...]. “Our subsequent studies (not reported here) on solar modulation of various blocking indices have confirmed previous studies, and we stress that this phenomenon is largely restricted to Europe and NOT GLOBAL in extent.” These are really just local mechanisms? No, it was not local, and will not be, warm and cold anomalies Temperature proxy records covering the last two millennia: a tabular and visual overview Ljungqvist, 2009: “The records show an amplitude between maximum and minimum temperatures during the past two millennia on centennial timescales ranging from c. 0.5 to 4°C and averaging c. 1.5–2°C for both high and low latitudes, although these variations are NOT ALWAYS OCCURRING SYNCHRONOUS. Both the Medieval Warm Period, the Little Ice Age and the 20th century warming [...] are CLEARLY VISIBLE in most records ...” High-resolution isotope records of early Holocene rapid climate change from two coeval stalagmites of Katerloch Cave, Austria, Boch et al., 2009: “Our record also shows a distinct climate anomaly around 9.1 kyr, which lasted 70-110 yr and showed a maximum amplitude of 1.0‰, i.e. it had a similar duration and amplitude as the (central) 8.2 kyr event. Compared to the 8.2 kyr event, the 9.1 kyr anomaly shows a more symmetrical structure, but onset and demise still occurred within a few decades only. The different progression of the 8.2 (asymmetrical) and 9.1 kyr anomaly (symmetrical) suggests a fundamental difference in the trigger and/or the response of the climate system. Moreover, both stalagmites show evidence of a climate anomaly around 10.0 kyr, which was of comparable magnitude to the two subsequent events. Using a well constrained modern calibration between air temperature and δ18O of precipitation for the study area and cave monitoring data (confirming speleothem deposition in Katerloch reflecting cave air temperature), a maximum cooling by ca 3°C can be inferred at 8.2 and 9.1 kyr, which is similar to other estimates, e.g., from Lake Ammersee north of the Alps.” Once again, Lockwood (and underestimated here: mechanisms): “This grand solar maximum has persisted for longer than most previous examples in the cosmogenic isotope record and is expected to end soon.” “... ~ 8% chance that the Sun could return to Maunder minimum CONDITIONS within the next 50 years. The connections reported here indicate that, despite hemispheric warming, Europe could well experience more frequent cold winters than during recent decades.” 8% - too small? -
Johnny Vector at 23:48 PM on 5 July 2010Archibald’s take on world temperatures
Also note how the snow cover graph is presented with the y axis starting at 35 million km2. Which is okay if you're concentrating on anomalies, except... He draws it as a bar graph. A bar graph is used to convey information by means of the relative areas of the bars, and as such must start the y axis at zero to give the correct impression. Looking at that graph makes it seem that the snow cover in 09-10 was twice the average. A line graph, or a bar graph with zero shown, would not give that incorrect impression. The difference right there, between damned lies and statistics. -
Peter Hogarth at 23:46 PM on 5 July 2010Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
Arkadiusz Semczyszak at 21:40 PM on 5 July, 2010 It is unlikely that you have read all of the references (yet) but this is forgivable. To then state that I have cherry picked (in the biased sense you mean) I find truly amazing, when you select three references, two of which appear to contradict each other even in your brief quotes in the comment? The irony may amuse any rational observer. However, genuine thanks for these, I will read them with an open mind and get back to you on these specifically. Papers which propose alternative explanations I usually find interesting. To provide links would be nice. On the article, I believe I have taken a fair slice of what is out there, more a shake of the tree than "picking" anything. It is true that I selected references from an even wider pool, but I can say with honesty that of the two hundred or more recent papers that I looked at and could have used, these are the most accessible, and the least dependent on pure modelling approaches. It is possible (and probable) that I have missed many, but this was not due to any conscious bias. In my opinion your comment about "the truth" does reveal bias. "Weight of evidence" allows for uncertainty, "truth", in your sense, does not. I have used plenty of AO references, and references for direct Arctic sunlight measurements and dimming/ brightening short wave trends, long wave trends, wind etc etc. You specifically mention AO, how do you explain the fact that the temperature and melting have continued on what now appears to be an accelerating trend through a century of AO index variations? The correlation of temperature and SLP holds well from roughly 1950 to 2000 (a long time in climate trend terms), but appears to break down before and after this. Factors driving AO can modulate the regional temp and background melt rate, but appear unlikely to themselves drive the longer term trend based on the wider evidence. I am open to new data on this, as I am accumulating references on early instrumental work. -
Tony O at 23:34 PM on 5 July 2010Archibald’s take on world temperatures
I sort of discounted David Archibald when he came up with the "we need 1,000 ppm" CO2 figure. -
JMurphy at 23:22 PM on 5 July 2010Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
Arkadiusz Semczyszak wrote : Extensive literature, but ... still the classic "cherry picking" ... It would be all right if not for the fact that here indicated, that ... ... AO is the dominant determinant of what happens in the Arctic of ice - of course it is indisputable fact ... Therefore, I recommend two very new product literature (they tell the truth about what winter in Europe, N. America and Asia, but add that the most important influence on the AO has a SUN ...): Interesting that you mention 'cherry-picking', 'truth' and 'fact' (twice) when you choose to use three sources, two of which are not as thoroughly peer-reviewed as any given in the article, and only one of which actually tries to claim that it disproves AGW - well, sort of. The first paper is published online on FACTS AND ARTS, a Finnish Internet Publication who "offer professional providers of high-quality material direct access to a worldwide, well-educated audience." All very noble but hardly in the same league as The American Meteorological Society or Geophysical Research Letters, for example, and yet you choose to pick it and claim it as being the 'truth' and 'fact'. Here is the link. The comment you refer to is a reply to an online comment from a fan of the article. Again, you chose to highlight it. As for the Lockwood paper, you may have missed this part of it : We stress that this is a regional and seasonal effect relating to European winters and not a global effect. Average solar activity has declined rapidly since 1985 and cosmogenic isotopes suggest an 8% chance of a return to Maunder minimum conditions within the next 50 years (Lockwood 2010 Proc. R. Soc. A 466 303–29): the results presented here indicate that, despite hemispheric warming, the UK and Europe could experience more cold winters than during recent decades. Lockwood is also on record as saying : "This year's winter in the UK has been the 14th coldest in the last 160 years and yet the global average temperature for the same period has been the 5th highest. We have discovered that this kind of anomaly is Significantly more common when solar activity is low." Your final paper is also less certain than you think : We suggest that the most direct driver of the late-Holocene anomalies has been changes in the dominant atmospheric Circulation type. This seems likely in an area, where the modern temperature and precipitation values are highly variable depending on the changing circulation patterns. The anticyclonic circulation type, Currently associated with the highest summer temperature, is a strong candidate as the mechanism behind the warm and dry late-Holocene anomalies. A more detailed analysis of the links between the reconstructed temperature patterns, inferred circulation changes, and the key late-Holocene forcing factors, such as the variability in ocean surface temperatures, solar irradiance, aerosols, greenhouse gas concentrations, and more complex combinations of these and other forcings, requires a more coherent analysis involving model experiments and will be a major palaeoclimatological task in the future. This also appeared in a less-conventional peer-review process (Climate of the Past) than normal : The process of peer-review and Publication in the interactive scientific journal Climate of the Past (CP) differs from traditional scientific journals. It is a two-stage process involving the scientific discussion forum Climate of the Past Discussions (CPD), and it has been designed to use the full potential of the internet to foster scientific discussion and enable rapid publication of scientific papers. All very noble again, and yet, again, you preferred it to any other paper, even though it says nothing that is that controversial - except you tried to higlight just one part of it. Why do you prefer to pick and choose the papers you like ? Why do you use words like 'truth' and 'fact' and yet don't back up those words ? Why, in fact, do you prefer to believe anything but AGW ? -
tobyjoyce at 23:09 PM on 5 July 2010Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
Arkadiusz Semczyszak @5 I followed up on these papers. These are a bit disapponting. (1) The Ahlbeck paper is a local study of AO effects at Turku, Finland, a city on the Baltic Sea, not the Arctic Ocean. (2) I need only quote from Lockwood et al : "We stress that this is a regional and seasonal effect relating to European winters and not a global effect" (3) I was unable to obtain anything more than the abstract of the Seppa paper, but it applies clearly only to Northern Europe, not the Arctic. These seem to me to be insufficient to cast any doubt on the papers quoted in the post, or to justify the accusation of "cherry picking". They are clearly dealing with different topics. -
Riccardo at 22:54 PM on 5 July 2010CO2 is Good for Plants: Another Red Herring in the Climate Change Debate
As expected by many, in this case also there's not just CO2, other limiting factors may come into play. And they may depend on the particular specie under study. A new study published in Nature (Langley et al. 2010, paywalled) shows a CO2 fertilization effect on C3 sedge and C4 grasses only in the first year. Supplying N together with CO2 "strongly promotes the encroachment of C4 plant species that respond less strongly to elevated CO2 concentrations. Overall, we found that the observed shift in the plant community composition ultimately suppresses the CO2-stimulation of plant productivity by the third and fourth years." More generally, one may think that profound changes in the ecosystem might be produced by changing atmospheric (and/or soil) chemical composition. Adding changes in temperature and precipitations it's easy to envisage hard times ahead for the Earth System Models. -
Esop at 22:33 PM on 5 July 2010Archibald’s take on world temperatures
#10: The El Nino is of course contributing to the temperatures these days, but it is interesting to see that a mild El Nino is enough to completely eclipse the cooling effect of the deepest solar minimum in more than a century, not just that, but we are setting all time temperature records as well. Quite the opposite of the Maunder minumum like conditions predicted by "skeptics" only 16 months ago. -
greenhousegaseous at 22:17 PM on 5 July 2010Climate cartoon: when positive is a negative
It isn't a matter of being "politically correct", but of trying to improve our collective (so far) dismal track record of explaining climate science to a largely ignorant voting public. My background is econometric modeling as well as engineering, but I would be happy to help develop *any* alternative verbal (or conceptual) constructs that can help reduce the present confusion regarding climate change, and climate change modeling in particular. Those of us with specialized technical backgrounds all too often demand the general public first accept our often arcane terminology before being permitted to share our knowledge. Then we resent the mass media for misrepresenting the science. The cartoon is therefore right to call our attention to one of the most common examples of unintentional modeling obfuscation. We desperately need to clarify all this stuff in a way that helps the voters of the advanced democracies get behind greenhouse gas reduction programs. You can lead a bunch of horses to a drying water hole, but you can't make them think. Greenhouse Gaseous -
skywatcher at 22:02 PM on 5 July 2010Archibald’s take on world temperatures
HR @ #6: The point wasn't that the 24.6m sq km was particularly unusual - it wasn't, and was reported as only the 13th lowest [unusual, maybe but not near record-setting]. The point was that this data is utterly in contradiction to what Archibald was pretending it might mean. We've actually got low snowcover, but by some clever cherry-picking, Archibald can pretend it's high. Winter snowcover is on the whole not temperature-driven, while the summer snowmelt is, as mspelto points out above, so concentrating on winter snowcover tells you more about the precipitation events that dumped the snow. Result - they were unusually high. Reason - increased water vapour due to greenhouse warming? -
Arkadiusz Semczyszak at 21:40 PM on 5 July 2010Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
Extensive literature, but ... still the classic "cherry picking" ... It would be all right if not for the fact that here indicated, that ... ... AO is the dominant determinant of what happens in the Arctic of ice - of course it is indisputable fact ... Therefore, I recommend two very new product literature (they tell the truth about what winter in Europe, N. America and Asia, but add that the most important influence on the AO has a SUN ...): Future low solar activity periods may cause extremely cold winters in North America, Europe and Russia, Ahlbeck, 2010; (“In this report I analyzed the statistical relation between the Quasi-Biennial Oscillation index (QBO is a measure of the direction and strength of the stratospheric wind in the Tropics), the solar activity, and the Arctic Oscillation index and obtained a statistically significant regression equation.”) ... and comment by the author: “But people who do not believe in the ability of the sun to change the climate significantly (in this case the winter weather south of 65. deg.) should know that the influence of solar activity on the winter temperature is statistically significant, which cannot be shown at all for the carbon dioxide concentration. All runs I did with atm. carbon dioxide concentration as independent variable resulted in elimination of this variable as STATISTICALLY INSIGNIFICANT. [...]" Are cold winters in Europe associated with low solar activity? Lockwood et al., 2010 (one of the co-authors: Solanki). Wider context of the role of the SUN is best seen here: Last nine-thousand years of temperature variability in Northern Europe, Seppä et al., (2009).: “The colder (warmer) anomalies are associated with increased (decreased) humidity over the Northern European mainland, consistent with the modern high correlation between cold (warm) and humid (dry) modes of summer weather in the region. A comparison with the key proxy records reflecting the main forcing factors does not support the hypothesis that solar variability is the cause of the late-Holocene centennial-scale temperature changes. We suggest that the reconstructed anomalies are typical of Northern Europe and their occurrence may be related to the oceanic and atmospheric circulation variability in the North Atlantic–North-European region.” -
Riccardo at 21:36 PM on 5 July 2010Archibald’s take on world temperatures
HumanityRules, from the data you can determine if a change is statistically significant or not, there's no such thing as absolute "too much" or "not that much". You can also determine the minimum period of observations (or number of observations) for a given variability to get significant results. A tiny few percent of decrease per year may appear to be small, but in 100 years you're left with a few percent of the initial value. So the problem is how far you're looking. -
neilrieck at 21:17 PM on 5 July 2010Climate cartoon: when positive is a negative
I hope we're not getting too politically correct in our terminology. The phrases "positive feedback" and "negative feedback" were first used by engineers in the 1930's who were developing amplifiers for the national telephone system. http://en.wikipedia.org/wiki/Positive_feedback#In_electronics As a rule, negative feedback is good while positive feedback is bad. -
HumanityRules at 21:12 PM on 5 July 2010Archibald’s take on world temperatures
Esop Don't start quoting June-June periods somebody might accuse you of cherry-picking. El Nino might go some way to explain things. -
mspelto at 21:10 PM on 5 July 2010Archibald’s take on world temperatures
The snow extent misses a more important discussion. There are two parts to the snow season. The winter season when the snowcover expands and the snow melt season when the snowpack is lost. The latter is more temperature dependent the former more storm track dependent. This winter did have quite high snow cover extent. The truly historic aspect has been the melt off which has been highest by far in the last 44 years. We went from the third highest snowcover in the last 44 years in Feb. to the lowest snowcover in 44 years in April and again in May. -
HumanityRules at 21:09 PM on 5 July 2010Archibald’s take on world temperatures
"An obvious great Pacific climate shift is not so evident" There is something very significant about the period around the 1970s. It seems to appear as an important feature in many climate data sets. A rather important eaample might be radiative forcing, images often show things really taking off around this time.
I don't see any harm in investigating other possible phenomenon that may explain this notable period. I agree though his terminology may be mis-leading.
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Esop at 21:00 PM on 5 July 2010Archibald’s take on world temperatures
We just completed the warmest 12 month running period on record. Not a good time to claim that the world is cooling. Even Svensmark is keeping quiet about his sunspot theory these days. Highest global average temperature on record during the lowest solar activity in more than a century was the death blow to the theory that the solar cycle is the main driver of global average temperature. -
Baa Humbug at 20:56 PM on 5 July 2010IPCC were wrong about Amazon rainforests
personally I believe those who are presenting the next report will be a little more careful in "translating" what a given paper concludes. I believe it's a good thing if the presenters know their words will be scrutinized by (literally) thousands of people. Less chance for "hype" don't you think? Did you find any benefits JMurphy? or is that a silly question? p.s. I'll bge away from my computer for a few hours. Apologies if I don't respond straight away. -
HumanityRules at 20:47 PM on 5 July 2010Archibald’s take on world temperatures
Thanks, a link to the report you quote might be useful. It strikes me 24.6msqkm is >98% of the average (if the anomly that year was 0.4). That doesn't seem like a great disaster and it seems fair to suggest it could well be little more than natural noise. It would be hard to believe that 2% variation is much outside the error margins of the methodology. In my field of work I wouldn't get too excited by a 2% drop in anything and I don't have to work with anything as chaotic as the planets climate. Dappledwater at 19:18 PM on 5 July, 2010 "What does Archibald think is causing the worlds ice sheets and glaciers to melt?." AMO maybe. -
JMurphy at 20:38 PM on 5 July 2010IPCC were wrong about Amazon rainforests
Baa Humbug wrote : And the hours "wasted" are mine to waste, but you get the benefit of anything positive that may come out of it. Not something to complain about I would have thought. And what are the real benefits that you believe have come out of your work ? -
sleepership at 20:26 PM on 5 July 2010Archibald’s take on world temperatures
Dappledwater all the denial crowd says there is no melting in the Arctic and Greenland- they also say we are not warming, but cooling- they are given so much attention because we have a Media- that 'believes' a small group of people with bogus information needs to be heard- while the other 97% of scientists who have robust science needs to questioned and investigated for large 'errors' they have committed. The media Titans in the USA need advertising dollars- so they print junk from the Denialists--they may lose their anti science sponsors- their revenues may be reduced-its all about money-not the truth. -
Baa Humbug at 20:24 PM on 5 July 2010IPCC were wrong about Amazon rainforests
JMurphy at 19:31 PM on 5 July, 2010 "How long before they gather the torch-bearing mobs ?" Awww don't be such a drama queen. I give you my word I won't bear any torches nor will I hang out with mobs. OK? -
Baa Humbug at 20:21 PM on 5 July 2010IPCC were wrong about Amazon rainforests
JMurphy at 19:48 PM on 5 July, 2010 wrote.. "Come off it - you cannot be serious ? They would have highlighted (and it would have been passed onto and through every blog in the denialosphere) ANY true scientific statement which hadn't been properly sourced". I am serious. They (meaning me as I was one of the auditors)were not given such a brief. Please do read the section titled "Quality Assurance". http://www.noconsensus.org/ipcc-audit/quality-assurance.php You also said.. "And to be fair about Pachauri's quotes, he usually talks about the conclusions, the science and the assessments being based on peer-reviewed science, and that is obviously correct". I refer you to my comment at #56 where I said... "The audit did not comment on the science nor did it comment on whether certain references should be included, or not, from the AR4". You conclude with... "You can be certain that it will be even more rigorous than the last one and many of you can waste many hours checking the fine detail for any human error". I would have thought it was a good thing to check such an important document for errors. We would want the errors, (if any) corrected wouldn't we JMurphy? And the hours "wasted" are mine to waste, but you get the benefit of anything positive that may come out of it. Not something to complain about I would have thought. -
JMurphy at 19:48 PM on 5 July 2010IPCC were wrong about Amazon rainforests
Baa Humbug wrote : For those who are interested in finding out how many references SHOULD HAVE BEEN peer reviewed but were not, bulk of the work has been done, download the Audit reports and go through the 5,587 non-peer reviewed references listed and find out for yourself. maybe you'll find 90% of the list DIDN'T need to be peer reviewed, that would leave 560 non-peer reviewed references. Whether that's too high or not is subjective and would probably make a good blog post one day. Come off it - you cannot be serious ? They would have highlighted (and it would have been passed onto and through every blog in the denialosphere) ANY true scientific statement which hadn't been properly sourced. The fact that certain people are obssessing about the Amazon one, shows how meagre the crumbs are from this so-called audit. And to be fair about Pachauri's quotes, he usually talks about the conclusions, the science and the assessments being based on peer-reviewed science, and that is obviously correct. Just because there are other sources used doesn't get away from that basic fact. Generally, though, why can't so-called skeptics move on and see what the next report says. You can be certain that it will be even more rigorous than the last one and many of you can waste many hours checking the fine detail for any human error. -
JMurphy at 19:31 PM on 5 July 2010IPCC were wrong about Amazon rainforests
Willis Eschenbach wrote : How does invalidating two references, neither of which I cited, change that? Leaving aside the dubious origin of your 'cites', as I have already cited above : "Citizen Audit failed to classify book chapters that are actually peer reviewed papers as "peer reviewed". They also fail to place IPCC self-citations, which are peer reviewed, into the peer reviewed category. The IPCC self-cites are some of the most expert reviewed literature ever." And as I already acknowledged that you hadn't used those actual references, reference to them was to show how untrustworthy that whole audit is. And that is just on a cursory glance : who knows what else will be found after a detailed proper audit ? But who has the time and energy to spend on deflating all these skeptical bubbles ? You did however copy and paste the COPA COGECA, 2003a reference - Why would you expect that to be peer-reviewed ? (The same goes for COPA COGECA 2003b.) As for your statement "Unfortunately, science requires more than heartfelt belief ...", that explains why the so-called skeptics have to rely on faith and hope for their beliefs. They way they obssess about certain matters and automatically disbelieve any scientist they don't want to believe (except their lone, and lonely, gurus, of course), is a definite act of faith and belief. How long before they gather the torch-bearing mobs ? -
Baa Humbug at 19:26 PM on 5 July 2010IPCC were wrong about Amazon rainforests
JMurphy at 02:58 AM on 5 July, 2010 Before anyone declares "errors" in the Citizens Audit report, they need to understand what the audit was all about. How else would one know if something is an error or not? The following is from the Audit Results website ... http://www.noconsensus.org/ipcc-audit/quality-assurance.php "The IPCC chairman has declared that non-peer-reviewed research sources belong in the dustbin (see the last lines of this newspaper article) but this project does not necessarily take that position. Its primary goal was to determine whether the chairman's claim (frequently repeated by journalists) that this report is based only and solely on peer-reviewed literature is accurate". The audit did not comment on the science nor did it comment on whether certain references should be included, or not, from the AR4. All the audit did was to list in detail what is/isn't a peer reviewed reference. Most certainly, many references in the AR4 did not need to be nor could be expected to be peer reviewed. Population statistics is a good example. For those who are interested in finding out how many references SHOULD HAVE BEEN peer reviewed but were not, bulk of the work has been done, download the Audit reports and go through the 5,587 non-peer reviewed references listed and find out for yourself. maybe you'll find 90% of the list DIDN'T need to be peer reviewed, that would leave 560 non-peer reviewed references. Whether that's too high or not is subjective and would probably make a good blog post one day. maybe JMurphy is up to the task? -
Rob Painting at 19:18 PM on 5 July 2010Archibald’s take on world temperatures
What does Archibald think is causing the worlds ice sheets and glaciers to melt?. -
skywatcher at 19:13 PM on 5 July 2010Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
This is a superb resource for recent research on Arctic sea ice. I'm going to bookmark it and use it myself as a paper source! Many, many thanks Peter. -
daniel at 18:49 PM on 5 July 2010Sea level rise is exaggerated
doug_bostrom at 06:42 AM on 4 July, 2010 There is only one Daniel KR at 02:08 AM on 4 July, 2010 "Sorry about the mis-reference to temperature, instead of sea level - proof that I sometimes don't proof-read enough!" Yes, but it's not just you that's doing it both Doug and Peter have also skimmed over what I've said and quickly responded with fervour without actually understanding my point. I would like to highlight the fact that these issues are highly emotive and the fears people have from your side of the argument are clouding your judgment. This is occurring both on this and other points of the debate and is clearly evidenced by all of your comments during this discussion. "The least justified fit is a line that avoids your data points. " Have I proposed such a fit? I have proposed short term fits within the error estimates of the data points. "Given the noise in that simple reconstruction, it's reasonable to time-average data points, especially for the recent (dense, somewhat noisy) data points.” I agree but I don’t see the relevance, you cant compare that recent, directly measured, high resolution, short term to the uncertain, low resolution, long term data set like that. “Note that the core samples have some implicit time averaging - it takes time for vegetation to grow, and the sample investigated is not going to be a 2D core slice; the thickness of it (and is the sediment flat there?) will introduce some time averaging. I didn't see that explicitly stated in the paper, but that's a known element for core analysis - you don't tend to see day-to-day changes in them!" I can't say I follow you here. My understanding is that the time uncertainties are from the C14 analysis. The researchers can only obtain a date range (from a non-Gaussian probability function) using this method. It doesn't give you a range on the order of days or months but years. "Either way - the reconstruction best justified from the evidence in this experiment should pass through or very close to each of the data points or averages. The data "anchors" the reconstruction there, and any large deviation from the trend (excursion) would have to either (a) show as a shifted data point, or (b) occur between data points - and vanish again before the next one. " I'm sorry but you are not addressing the long term / short term issue. I will say again that I agree with the proposed long term linear trend and the data allows for short term deviations not too far from the data points that would undermine Donnelly’s conclusions. "However, there is in this experiment actual evidence against offsets from the reconstructed sea level trend around the data points themselves." Explain. Peter Hogarth at 03:42 AM on 4 July, 2010 "If there were short term variations of the magnitude which you suggest between the sparse points then the probability of all of these randomly sampled points fitting any smooth long term curve is small." Maybe you are finally understanding my point. You're right that on the short term scale the probability of the long term trend is small, thankyou. :) "Any extra points we find which also fit the curve increases the probability that the curve is a good model, and constrains other probable models to those with low amplitude variations." There aren't any more data points provided and if more data points showed that there was a low amplitude variation from the linear trend then the recent uptrend would look less alarming, more precedented or natural and much less anthropogenic or induced by CO2. "With respect, if this is lost on you, then I understand why you keep re-iterating your point, and you should address this." It's not lost on me Peter, as far as I can see you are trying to use wordy rebuttals that don't amount to much. There is not enough resolution to determine that thre is a long term linear trend that barely deviates on the short term. More importantly as long as there are large enough uncertainty levels the recent uptrend will never be shown to be unusual. If you reconstruct the data Peter from table 1., just use the absolute centres of the boxes, you will see that using sample 1 (dated ~1975) along with the other data points the trend stays much the same (possibly even lowers a little) and so the entire trend over the last 700 years is still ~1mm/yr at Barn Island. I hope that addresses your “undersampling” or “Unlikely wild deviations” tack. The instrumental record is showing us that the Donnely reconstruction may in fact be an undersampling of a natural higher amplitude trend. "I am arguing that Donnelly is presenting work that is specialist." Ad hominem "His data is site specific and is intended to add a small piece to the unfolding picture which is science, rather than act as first line defence against "climate skepticism" Undoing the poor science of climatology is the first line of attack when it comes to this debate. Their methods may be scientific in nature but their conclusions seem to be biased, driven by an unfounded fear of gloom and doom. "That you accept that drivers of sea level should be accounted for is a good step, yet you still do not appear to modify your suggestion of "likely" high sea level variations in light of this. This is not scientific" It has not been shown from this data that the uptrend is un-natural and therefore it is not necessarily anthropogenic. To claim otherwise is unscientific. -
dansat at 18:24 PM on 5 July 2010Archibald’s take on world temperatures
I love cherries, they are so tasty when freshly picked. -
John Chapman at 18:15 PM on 5 July 2010Archibald’s take on world temperatures
Point taken. I should have said there is no persuasive evidence that the world is cooling which was the message. -
tobyjoyce at 17:49 PM on 5 July 2010Archibald’s take on world temperatures
Philosophically, if you make a positive claim (e.g. "the earth is warming"), then you must produce empricial evidence for the claim. To rebutt such a claim (e.g. "the earth is not warming"), you must induce reasonable doubt by using the original evidence and/ or new evidence previously not considered. So I think a better response to Archibald is to say "The evidence for global warming has not been rebutted by his data" Massimo Piglucci has a good post on the "burden of prook" here: Burden of Proof -
Riccardo at 17:02 PM on 5 July 2010Arctic Ice Part 2: A Review of Factors Contributing to the Recent Decline in Arctic Ice
Peter, terrific work, it will take months to digest. Thank you for sharing it with us. -
Willis Eschenbach at 16:43 PM on 5 July 2010IPCC were wrong about Amazon rainforests
JMurphy at 00:06 AM on 5 July, 2010Returning to the so-called 'citizens audit' of the IPCC, it would appear that they have mis-classified another reference.
Whoa, two errors? JMurphy, there are definitely questions about some of the classifications in the audit of the IPCC report. And yes, some of them are clearly in error. However, this does not invalidate what I cited. I've given you dozens and dozens of non peer-reviewed citations to things like newspaper and magazine articles and WWF and Greenpeace articles. How does invalidating two references, neither of which I cited, change that? -
Willis Eschenbach at 16:32 PM on 5 July 2010IPCC were wrong about Amazon rainforests
doug_bostrom at 17:06 PM on 4 July, 2010Ho-hum, Willis has gone off down the Amazon rabbit hole yet again. I suppose it would best to get Nepstad's entire statement out here so Willis can deal with it in detail.
Thanks, Doug. I'll do that very thing. Nowhere in your Nepstad quote does he show that the IPCC claim is in the peer reviewed literature. He says that:Our 1999 article (Nepstad et al. 1999) estimated that 630,000 km2 of forests were severely drought stressed in 1998, as Rowell and Moore correctly state, but this forest area is only 15% of the total area of forest in the Brazilian Amazon.
That was the only paper cited by Rowell and Moore as their reference for the claim. But that's not what the IPCC claim said. And Nepstad accepts that. He says:The IPCC statement on the Amazon is correct, but the citations listed in the Rowell and Moore report were incomplete.
OK, we see he thinks the IPCC statement is correct, and he admits that citing his 1999 paper didn't support the claim ... but he neglects to give us a peer-reviewed citation showing that it is correct. I understand that he believes it, Doug, but belief is not what we're looking for. We're looking for peer reviewed studies, not simple credence. The WWF later said the claim was from an earlier IPAM document. This also turned out to be untrue. So that couldn't be the citation that would complete the citations listed in the Rowell and Moore report. So if the citations in the Rowell and Moore are "incomplete" as Nepstad said, and the IPAM document doesn't "complete" them, what citation should have been made to "complete" the Rowell and Moore paper? Nepstad would have us believe that to complete their citations, they should have cited the 2004 Nepstad et al. paper. In their 2004 paper, Nepstad said that "half of the forest area of the Amazon Basin had either fallen below, or was very close to, the critical level of soil moisture below which trees begin to die in 1998." But that's not the claim made by the IPCC either. All that the Nepstad 2004 paper shows is that there was a big drought in the Amazon, and that the Amazon did not experience either the "drastic reaction" or the "climate shift" that the IPCC warns of. So that doesn't support the Rowell and Moore/IPCC claim either. In fact, Nepstad 2004 tends to show that the Amazon is more stable than they claimed, rather than show it is very sensitive as they would like us to think. Finally, is Nepstad 2004 the citation that Rowell and Moore should have listed to "complete" their citations? That's not even theoretically possible. I leave it as an exercise for the reader to figure out why ... So all Nepstad has done is agree that the citations to Rowell and Moore are incomplete. He has not given us a single reference to complete them by showing where their 40% claim, or their danger of an impending climate shift claim, is valid. As I said, even George Monbiot has given up on your claim, Doug, saying:It is also true that nowhere in the peer-reviewed literature is there a specific statement that "up to 40% of the Amazonian forests could react drastically to even a slight reduction in precipitation".
And contrary to your claim, Nepstad has not given us such a citation in the quote you reproduce above. Monbiot knows about Nepstad's quote, and he couldn't find the answer in Nepstad's quote. Or outside his quote. I can't find one either. And neither, apparently, can you ... you just keep recycling Nepstad's heartfelt statement that he believes it is true. Look, I know that Nepstad believes it, that's obvious. Unfortunately, science requires more than heartfelt belief ...
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