Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.

Settings

Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup

Term:

Settings

Beginner Intermediate Advanced No Definitions Definition Life:

All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Recent Comments

Comments 127901 to 127950:

Philippe Chantreau at 03:08 AM on 13 July 2009

Climate time lag
You can not attribute everything to a cycle,especially since neither DO events, Heinrich events or Bond events have been shown to be truly cyclic in nature. The periodicity of Bond events is estimated by Bond himself with a very large uncertainty. Your sampling bias complaint is unfounded. The data are there, they simply do not show synchronous hemispheric warming with D-O events. The Bipolar Seesaw shows up during the periods considered: http://www.scenta.co.uk/environment/news/cit/1271676/bipolar-seesaw-connects-the-poles.htm Excerpt: "the Antarctic starts to cool every time more warm water starts to flow into the North Atlantic during warm events in the north." NOAA has a nice discussion: http://www.ncdc.noaa.gov/paleo/abrupt/data3.html This article is interesting too: http://www3.interscience.wiley.com/journal/82002936/abstract?CRETRY=1&SRETRY=0 Robbo's link to the Wikipedia article on Bond's events: "the only Holocene Bond event that has a clear temperature signal in the Greenland ice cores is the 8.2 kyr event." The main difference between Bond and DO events is that Bond events are of much smaller nagnitude. Although the oceanic circulation pattern suspected in DO events appears to be conserved, it does not seem to be significant climatically in most cases. The Loehle E&E thing that you link makes no mention of Bond events. Except for not being dendro, what are the data used by Loehle? Your link does not say what the proxies are, where they were gathered, by whom, there is no data publication referenced, just Loehle's own compiled file in excel, which does not really help.

Thumb at 01:15 AM on 13 July 2009

Climate time lag
#27: "Let’s neglect the unlikely 6 month rise... We should have had either atmospheric or ocean temperature or both increase – but we have had neither. This effectively falsifies AGW theory." Well I'm convinced. Science is easy.

thingadonta at 22:20 PM on 12 July 2009

Climate time lag
re 29: Yeah, a 500 year long, one hemisphere phenomenon. Haven't the IPCC ever heard of sampling density bias? If they are fewer studies in the southern hemisphere, this donest mean it didnt occur there. This is a typical socialist type misinterpretation-ie sampling density/occurrence correlates with fact/importance. I have seen this sort of bias in socio-economic analyses conducted by the public service, which attributes vocation significance/indices to actual number employed in an industry, rather than wages and other factors etc. So doctors, at less than 1% by number in a region, can be done away with....not to mention commuters, investors, etc etc-but I digress.... The chinese have kept good records, and have a strong medieval warm period, as do the Japanese. NZ was settled during this time around AD1000, just like Greenland (which may or may not be correlated, its just interesting), and glacial advances/retreats have actually been dated in NZ and are in line with european glacier advances/retreats. Mayans and Aztecs empires were disrupted by severe droughts. Easter island agriculture declined as T got colder from the time of settlement around ?AD800 (although other factors were also probably at work there). Anyway, the medieval warm period in the southern hemipshere has been detailed by much better methods than the above speculations, and keeps showing up in the data: it isnt a greenland phenomenon. I wonder if anyone has done a study of migrating agriculute in NZ's south and north islands since polynesian settlement around ?AD1000, this could show a trend if the south island for example got colder and farmign was abandoned, progressively moving north after the medieval warm period? I did read somewhere that the polynesians were attempting to grow tropical-type crops in places, but it got too cold for them, maybe they were moving progressively north as the islands went into the little ice age?? But I will have to find the reference. Also of interest, in the book "the Chilling Stars" by Danish solar scientists, a recently melted snow/ice pass in the European Alps in 2003 revealed various items left from both the roman and medieval warm periods-including shoes, clothes and the like-showing the pass was open and travelled in both previous warmings. These items were only exposed in 2003. A roman ruin is also located there, the locals finally found out what this old ruin was for, all the way up in those mountains-it was an ancient roman mountain pass lodging-only very recently reusable for travellers. So much for a greenland-only medieval warm period...

Robbo the Yobbo at 18:50 PM on 12 July 2009

Climate time lag
re28 G'day Thingadonta The 1500 year Dansgaard-Oeschger Events become Bond Events in the holocene. There are 10 references listed on Wikapedia and a reasonable summary. http://en.wikipedia.org/wiki/Bond_event There is a 2008 non tree ring reconstruction here: http://www.ncasi.org/publications/Detail.aspx?id=3025 which discusses the geographical problem and which, incidentally, shows the warm period as warmer than 1998. Is the IPCC still arguing that this was a Northern Hemisphere phenomenon and therefore it doesn’t matter. What would they imagine the ‘physical mechanism’ is behind that? And as for only Greenland warming. lol Cheers Robbo

Robbo the Yobbo at 18:07 PM on 12 July 2009

The CO2/Temperature correlation over the 20th Century
Seriously - did no one that the post confused sea surface temperatures and than near surface atmospheric temperature. There is a link by energy transfer but the series are measured in different ways. The temperature is measured in water - air temperature is measured in air. The fact that they both show cooling trends? Oceans surfaces cooled after the mid 1940's as did near surface atmosphere temperature. The warming and cooling was especially pronounced in the Arctic. Arctic air temperature change amplification and the Atlantic Multidecadal Oscillation Chylek Petr, Chris K. Folland, Glen Lesins, Manvendra K. Dubeys, and Muyin Wang: 2009: 'Arctic air temperature change amplification and the Atlantic Multidecadal Oscillation'. Geophysical Research Letters (in press). “Understanding Arctic temperature variability is essential for assessing possible future melting of the Greenland ice sheet, Arctic sea ice and Arctic permafrost. Temperature trend reversals in 1940 and 1970 separate two Arctic warming periods (1910-1940 and 1970-2008) by a significant 1940-1970 cooling period. Analyzing temperature records of the Arctic meteorological stations we find that (a) the Arctic amplification (ratio of the Arctic to global temperature trends) is not a constant but varies in time on a multi-decadal time scale, (b) the Arctic warming from 1910-1940 proceeded at a significantly faster rate than the current 1970-2008 warming, and (c) the Arctic temperature changes are highly correlated with the Atlantic Multi-decadal Oscillation (AMO) suggesting the Atlantic Ocean thermohaline circulation is linked to the Arctic temperature variability on a multi decadal time scale.” “In the following analysis we confirm that the Arctic has indeed warmed during the 1970-2008 period by a factor of two to three faster than the global mean in agreement with model predictions but the reasons may not be entirely anthropogenic. We find that the ratio of the Arctic to global temperature change was much larger during the years 1910-1970.” “We consequently propose that the AMO is a major factor affecting inter-decadal variations of Arctic temperature and explaining [the] high value of the Arctic to global temperature trend ratio during the cooling period of 1940-1970.” Again, ocean and atmospheric temperatures are heading down in this 25 year cycle. Which bit of multi-decadal oscillation is so hard to grasp?

Robbo the Yobbo at 18:06 PM on 12 July 2009

The CO2/Temperature correlation over the 20th Century
I suppose it is simple to not see the wods for the trees. The post did confuse sea surface temperatures and with near surface atmospheric temperature. There is a link by energy transfer but the series are measured in different ways. Water temperature is measured in water - air temperature is measured in air. They are a different data series and provide independant support for the mid century cooling.

Robbo the Yobbo at 17:59 PM on 12 July 2009

David Horton at 17:49 PM on 12 July 2009

The CO2/Temperature correlation over the 20th Century
When reading the amazing theses from Thingadonta, Robbo, and Quietman, I am constantly reminded of something you learn very early on when training to be a scientist - a certain aphorism by Mr Ockham.

thingadonta at 17:22 PM on 12 July 2009

Climate time lag
re24" "the Avery-Singer piece refers to Dansgaard-Oeschger events. There is an abundant litterature on the subject. These events appear to be mainly Northern hemisphere occurrences and only in Grenland did they produce large warmings" No. There is abundant literature, ignored by the IPCC, that nz, china, siberia,central america and other places warmed in line with Europe in the medieval warm period. To say it was confined to europe/greenland is not correct; IPCC selects eg another example of tree rings in TASSIE AND then compares them to urban heat islands in recent tassie, more of the same hockey stick rubbish, completely ignoring data from NZ and other places. IPCC should be called the international panel of cherry pickers. IPCP. Its detailed in the singer and avery book, and peer reviewd articles are listed. It was no confined to northern hemisphere and greenland etc. The 1500 year cycle is not even with time across its warming/cooling trends.

Robbo the Yobbo at 15:54 PM on 12 July 2009

Climate time lag
Is heat hiding in the molecule? ‘First, from 2004 to the present, steric contributions to sea level rise appear to have been negligible…Although the historical record suggests that multiyear periods of little warming (or even cooling) are not unusual, the present analysis confirms this result with unprecedented accuracy.’ ‘The rate of ocean mass increase based on GRACE during the study period is similar to previous estimates based on observed melting of land bound ice, which tend to be around 1 mm/yr [Shepherd and Wingham, 2007; Kaser et al., 2006; Rignot and Kanagaratnam, 2006; Velicogna, 2006; Chen et al., 2006]. However, most of the 3.5 mm increase seems to have occurred in a 6-month period between late 2004 and early 2005. On the other hand, the inferred estimate (Jason – Argo) implies a much greater rate of ocean mass increase and significant uncertainties in the trend over the GRACE record remain. Until these issues are resolved, the long-term rate of ocean mass increase remains uncertain.’ http://ecco.jpl.nasa.gov/~jwillis/willis_sl_budget_final.pdf Let’s neglect the unlikely 6 month rise and assume a mass sea level rise of 5mm over 2004 to 2008. Using the area of the ocean and the enthalpy of fusion for water (use Wikipedia) gives a total enthalpy of 5.6 x 10 to the power of 20 J – about 1/250th of the total ocean heat content. This of course is heat converted to internal kinetic energy – i.e. hiding in the molecule. Even if we increase the non steric sea level rise by an order of magnitude - there is still a substantial energy deficit. This is heat that has to come from somewhere. The additional heat from IPCC net forcing is about 4 x 10 to the power of 22 J over the last 5 years – check my calcs (please check my calcs). We should have had either atmospheric or ocean temperature or both increase – but we have had neither. This effectively falsifies AGW theory.

Robbo the Yobbo at 12:06 PM on 12 July 2009

Climate time lag
There is an 11,000 year sunspot reconstruction on Wikapedia. It is of course based on the so called cosmogenic isotopes is ice cores. These are isotopes of carbon and beryllium that are formed when affected by ionising cosmic radiation. The amount of cosmic radiation hitting atmosphere is modulated by the heliosphere which is in turn associated with sunspot count. http://en.wikipedia.org/wiki/Solar_cycle I wouldn't get too caught up with looking for precise cycles - just note that it goes up and down. The heliosphere changes as a result of internal cycles in the Sun such as the 11 year cycle, the 22 year solar polar magnetic reversal cycle and with the orbits of particularly the large outer planets. The time periods associated with these cycles are averages – the heliosphere doesn’t change on cue or even smoothly. A reconstruction of heliospheric magnetic intensity – based on carbon 14 in ice cores – is found here. http://en.wikipedia.org/wiki/File:Carbon14_with_activity_labels.svg Note the ‘Modern Maximum’ which went off the chart last century. Might it be related to the syzygy of March 10 1982? At any rate, the magnetic intensity of the heliosphere is declining rapidly – a decline that will continue sporadically over the next few centuries. It is typical that the error bounds from this kind of research are greater the further back in time you go. The last thousand odd years have been correlated with temperature reconstructions. The 1000 year temperature reconstructions from tree rings and oxygen 18 are of course bounded by large potential errors. But both the temperature reconstructions and the very fallible and partial historic records suggest a high point in global temperature around 1000 AD – called the ‘Medieval Optimum’ – and a low point in the 1700’s called the ‘Little Ice Age’. The correlation is between cosmic radiation and global temperature. Conceivably there could be a link between the heliosphere and solar irradiance. However, it seems that solar irradiance does not vary significantly. This has led some to posit a more subtle connection of the heliosphere to climate through ionisation of aerosols and subsequent formation of cloud condensation nuclei. CERN is currently undertaking a program of experimental investigation of this physical process. A review of the correlations, the hypothesis and the experimental design is provided at: http://arxiv.org/abs/0804.1938 The movie version is available here: http://cdsweb.cern.ch/record/1181073/ Sunspots have been counted since soon after the invention of the telescope by Hans Lippershey in Holland in 1608. The low point is at 1650 to 1700 AD which is associated with very low temperatures in Europe and with low temperatures in the millennial temperature reconstruction. http://www.cru.uea.ac.uk/cru/info/milltemp/ Global temperature rose 1000 years ago, dipped to the 1700’s and has risen since very much in line with the cosmogenic isotope count. Note also the shorter term variation in temeperature. The instrumental record of global surface temperature again shows shorter cycles – noting again that the reliability of the data diminishes with time. Increasing to 1880, declining to 1910, increasing to 1945, declining to 1975, increasing to 1998 and declining to June 2008. There are other 20 to 30 year cycles. The Pacific Decadal Oscillation – a cool mode form the mid 1940’s to the mid 1970’s and a warm mode from 1976 to 1998. The PDO was initially defined in terms of a relationship between sea surface temperature in the north eastern Pacific and fisheries productivity. In a cool mode, cold and nutrient rich water upwells strongly boosting productivity. In a warm mode, the upwelling is suppressed. Biology suggests that the current cool mode commenced in after 1999. http://jisao.washington.edu/pdo/ ENSO also has 20 to 30 cycles. These can be seen clearly in the multi-variate ENSO index of Claus Wolter. http://jisao.washington.edu/pdo/ There was a notable shift in climate in 1976/77 known as the ‘Great Pacific Climate Shift’. It is no accident that the periods of warming and cooling of the Pacific sea surface and global near surface atmospheric temperature are the same. Is there a link between these phenomenon and neutron counts on a solar cycle? I don’t know and I don’t care. Clouds, oceans and atmosphere are physical systems with a lot of momentum when they get going. They are not switched on and off like a light globe. What does the cloud evidence say? From the beginning of reconstructions in 1984, Earth albedo decreased by 1% (3.4 Wm2) to 1998. In 1999/2000 Earth albedo increased by 0.6% (2 Wm2) and has essentially stayed there. http://www.bbso.njit.edu/Research/EarthShine/ It suggests a physical explanation for surface and ocean warming and cooling. Actual changes in shortwave forcing as a result of changes in cloud cover. I am more interested in how it might work as a cause of the PDO and decadal ENSO modulation. There is a layer of warm surface water overlaying colder subsurface water. Subsurface currents are driven by cold water sinking at high latitudes and by the rotation of the planet. Upwelling of cold and nutrient rich water occurs as a result of physical characteristics in a few spots – especially the north eastern Pacific and in the Humboldt Current off South America. A little surface cooling and cold water upwells strongly in the north eastern Pacific. A little surface warming and the upwelling is suppressed. The central Pacific undergoes the same heating and warming over which is superimposed the 2 to 7 year ENSO cycle. This is a theory that probably requires 20 more years of cloud data. Regardless of the cause, the PDO, the decadal modulation of ENSO and suppressed global near surface atmospheric temperatures are with us to about 2024. El Niño are weaker in cool PDO periods. The next El Niño will not be a 1998 event – and global surface temperatures will continue to fall. In the longer term, the evidence for a cosmic ray/ climate link is strong. This suggests a cooling influence over the next couple of centuries – regardless of the mechanism.

David Horton at 11:54 AM on 12 July 2009

The CO2/Temperature correlation over the 20th Century
"The Arctic is not about CO2. It's about tectonic plates." - what an astonishing coincidence then, that the unprecedented melt is happening just as temperatures rise with increasing CO2.

Philippe Chantreau at 05:39 AM on 12 July 2009

Climate time lag
Thingadonta, if the cycle is 1500 yrs and it last started in 1750, how can we be halfway through? Seems half way would be in 2500.

Philippe Chantreau at 05:33 AM on 12 July 2009

Climate time lag
Not really.Wouldn't explain how mountain glaciers are melting everywhere. From what I remember, the Avery-Singer piece refers to Dansgaard-Oeschger events. There is an abundant litterature on the subject. These events appear to be mainly Northern hemisphere occurrences and only in Grenland did they produce large warmings. Most analyses use Greenland ice cores. They are found throughout the latest glaciation until about 23000 yrs ago, where they no longer appear in the paleo record. Furthermore, some research also shows that, while the Northern Hemisphere warmed in DO events, the Southern hemisphere cooled. THe best explanations advanced so far postulates changes in ocean currents leading to changed heat distribution.

Quietman at 04:56 AM on 12 July 2009

Arctic sea ice melt - natural or man-made?
Patrick " 523. Should I be so optimistic as to expect a room of adults to agree that the sun is a star?" Maybe Not, LOL. Some think the Earth was created 6,000 years or so, and rely on prophets of Doom and Death. The wackos expect the Earth to end in 2012 and Hansen says were are "Toast". With wackos like this what can we expect.

Quietman at 04:48 AM on 12 July 2009

Climate time lag
Philippe Possible the AMO. I'm not sure. I have not read Cazenave's paper but it sounds about right.

Quietman at 04:44 AM on 12 July 2009

Climate time lag
Re: Lee Grable at 04:44 AM on 9 July 2009 Maybe you should take some lessons from the Real Climate website. They don't suffer fools over there. Cuts way down on the bitchiness. Real Climate is the worst possible propaganda site on the entire web. That's Hansen and buddies. Can't expect a skeptic view not to be derision there. Just asking a simple question results with a sarcastic answer, never a true answer. You can't trust any alarmist. It's like a scientific reason for a 6,000 year old Earth.

Quietman at 04:30 AM on 12 July 2009

It's the sun
Gord Re: "Don't understand?...It's OK....everybody else will." Sorry. I don't understand. I don't what is "Baghdad Ali".

Quietman at 04:17 AM on 12 July 2009

The CO2/Temperature correlation over the 20th Century
"We did not about the increase" s/b We did not KNOW about the increase

Quietman at 04:15 AM on 12 July 2009

The CO2/Temperature correlation over the 20th Century
Thumb The Arctic is not about CO2. It's about tectonic plates. We did not about the increase in the Arctic ridge until the past couple of years, It was even not about the under volcanoes erupted until they put together the quakes with the eruptions BEFORE the recent eruptions in Alaska. They also show the subduction zone in NE Greenland but they recognize the thin crust and hot spot and Greenland active volcanoes the "might add to the glacier melt". See the volcano threat here. http://www.skepticalscience.com/volcanoes-and-global-warming.htm

Dan Pangburn at 23:25 PM on 11 July 2009

It hasn't warmed since 1998
Since the year 2000, atmospheric carbon dioxide has increased 18.4% of the increase from 1800 to 2000. According to the average of the five reporting agencies, the trend of average global temperatures since 1998 shows no increase and from 2002 through 2008 the trend shows a DECREASE of 1.8°C/century. This SEPARATION (there have been many others) corroborates the lack of connection between atmospheric carbon dioxide increase and average global temperature. I wonder how wide the separation will need to get before the IPCC and a lot of others are forced to realize that maybe they missed something. As the atmospheric carbon dioxide level continues to increase and the average global temperature doesn’t it is becoming more and more apparent that many Climate Scientists have made an egregious mistake and a whole lot of people have been misled.

Mizimi at 21:56 PM on 11 July 2009

Climate's changed before
Thanks QM; an interesting article. I shall have to go and revisit clathrate physical/chemical properties. From what I recall, they only form under extreme pressure/low temperature conditions ( which is why they are mostly found in very deep water).

Mizimi at 21:34 PM on 11 July 2009

Water vapor is the most powerful greenhouse gas
There is considerable evidence that man's activities are changing the distribution of WV with consequential effect on climate. Deforestation has decreased evaporation by around 3000cubic/k/a which is mostly balanced by increases from agricultural evaporation of # 2600c/k/a. To that must be added the estimated loss of 400 c/k/a from industry, commercial, municipal use and reservoirs. The system seems to be in balance. However, the flow pattern of WV has changed, with subsequent effects on climate....this is explored from an agricultural view in "Human modification of global water vapor flows from the land surface." published online at PNAS ( the address is just too long to post) and the authors conclude that until modellers include redistribution of WV, GCM's cannot be considered to adequately describe real world conditions.

thingadonta at 20:13 PM on 11 July 2009

Was Greenland really green in the past?
Greenland was relatively warm between about 800-1300 AD due to the well-defined 1500 year solar cycle, as detailed by Singer and Avery in: "Unstoppable global warming every 1500 years". We are currently in another upswing in the solar cycle, which started about 1750, and which will probably rise about another 0.5-1 degree C over the next few hundred years. Current T to the 21st century is entirely in line with this solar cyle trend. C02 is irrelevant to this cycle,it has been traced 600 times over the last 1 million years in ice cores, and is a result of an overlap between the 87 and 210 year solar cycles. It is well documented, world wide, and climatologists have conveniently forgotten about it (see reference given above). Greenland was settled by vikings during the last solar warming period, which is also why they travelled so far in general during this time period-the northern world was warm.

thingadonta at 19:01 PM on 11 July 2009

Climate time lag
There is a 1500 (1470) year natural solar cycle, which is a superimposed 87 year and 210 year solar cycle overlap. It has been traced 600 times over the last 1 million years in ice cores, is very consistent, and we are currently about halfway through the latest solar warming trend, which started in about 1750; T will rise another 0.5-1 degree C over the next few hundred years, from the sun, as it has already risen about 0.8-1 degree C since 1750, also because of the sun. C02 is irrelevant to this trend. Current T is entirely in line with this well-defined 1500 year solar trend. Reference: "Unstoppable global warming every 1500 years" by F.Singer and D.Avery. They also trace numerous studies which confirm the trend, eg the medieval warm period, the little ice age etc etc.

Philippe Chantreau at 15:59 PM on 11 July 2009

Climate time lag
The Cazenave paper states that the sea level increase of the past 5 years is due to increase of the oceans' mass due to shrinking land ice, both from polar ice caps and mountain glaciers. It seems that perhaps that could prevent too much warming from comparatively modest forcings. There has to be a reason for all that ice to melt. It also seems to undermine your assertion about the "total energy in the system." We're missing big chunks of ice that have now become water. What is exactly the 1000 to 1500 years cycle that you refer to?

Robbo the Yobbo at 10:51 AM on 11 July 2009

Climate time lag
I wonder why the cloud nucleation should be instantaneuos and why there should be therefore an immediate link to the 11 year solar cycle. Ionised aerosols are much smaller than cloud condensation nuclei. It must take some time to coalesce into larger particles and then to accumulate water vapour. There is an obvious 20 to 30 year cooling and warming pattern in global temperatures - as well as longer (1000 to 1500 year) cooling and warming. Unless we can distinguish clearly between natural variation and anthropogenic global warming - the attribution problem is not solved. The heliospheric/cosmic ray/ cloud connection is the leading contender for a source of the variation on these timescales. The basis of the concept relies is in analysis of beryllium and carbon isotopes form ice cores. The correlation over more than a thousand years is best with a 10 year lag. But this is only a correlation. The essential question is, because it is fundamental to assumptions about TOA fluxes (and therefore the time lag and cimate sensitivity), is whether clouds are changing in reality and from observation - and what are the implications. Clouds decreased from 1984 (when the reconstructions commence) to 1998 - with an increased shortwave forcing at the surface of 3 to 4 W/ms. Cloud cover has subsequently increased decreasing the shortwave forcing by 2 W/m2. Ocean heat content has, at a minimum, not increased since 2008. That is clear in: Sea level budget over 2003–2008: A reevaluation from GRACE space gravimetry,satellite altimetry and Argo A. Cazenave a,⁎, K. Dominh a, S. Guinehut b, E. Berthier a, W. Llovel a, G. Ramillien a, M. Ablain b, G. Larnicol b Also in the recent work by Willis referred to elsewhere and the 2009 Energy and Environment Article by Loethe. At the same time the monthly values of global surface temperature continue to decline. People are hoping that surface temperature will reach a new record if an El Nino forms in the boreal summer. The strength of El Nino is statistically correlated with the state of the Pacific Decadal Oscillation. While the PDO is cool - it is hugely unlikely that a strong El Nino will form. NASA is predicting record temperatures when El Nino returns. It is not even close this year and we will return to La Nina next year. Energy can be transferred betwen the ocean and atmosphere - especially in ENSO events. However the total energy of the ocean and atmosphere (barring volcanos) cannot decline with the forcings given by the IPCC. It seems likely that there is less energy in the climate system today than in 2005. This is a serious problem for AGW theory. - although I am anticipating that Chris will argue that there is more energy. It is hiding perhaps under a rock.

shawnhet at 06:56 AM on 11 July 2009

Climate time lag
Philippe, you may not care for the tone of the Shaviv's reply, but it seems to me that the long-term correlation btw CRF and climate has very strong evidentiary support, whether or not it can be separated from noise for the short term. There are many papers that demonstrate such a correlation - see here for example. http://geology.gsapubs.org/content/37/1/71.abstract BTW, I would not be so quick to accept chris's assertion that there is no link btw CRF and clouds. In the discussion on Shaviv's page, he states the following: "The next criticism Sloan and Wolfendale raise is the fact that when the cloud cover is correlated with the cosmic ray flux over the 11-year solar cycle, it appears that the cloud cover leads the cosmic ray flux variations by about 3 months (see panel 2 of fig. 1 above). If cosmic ray flux affect the cloud cover, such a lead should not be observed." (Shaviv then goes on to discuss his reasoning why this objection doesn't apply). Cheers, :)

Robbo the Yobbo at 06:17 AM on 11 July 2009

Does ocean cooling disprove global warming?
Look - you can have a go at me but leave Freddy out of this. Svensmark-Friis-Christensen have obviously interpreted the data they present differently to you. But this was a paper that you originally introduced. Let's not worry about that - but concentrate on the peer reviewed work. To quote Jasper Kirkby – ‘The data for the period 1957–2001 show the solar cycle modulation and the effect of geomagnetic shielding, which leads to reduce fluxes and modulation amplitudes at lower geomagnetic latitudes (Fig. 7). Although the GCR reduction occurred mainly in the first half of the twentieth century (Fig. 6), the cosmic ray measurements shown in Fig. 7 suggest a continuing decreasing trend in the second half of the century, by a few per cent in the lower stratosphere and upper troposphere… On the other hand, there has been a substantial increase of solar magnetic activity since the Little Ice Age, and a corresponding reduction of the cosmic ray intensity. This suggests that the possibility of an indirect solar mechanism due to cosmic-ray forcing of the climate should be seriously considered.’ There is a cloud and cosmic ray correlation here – not sure how reliable it is. http://www.sciencebits.com/CosmicRaysClimate I don’t think it works like that – there is a lag between cosmic ray intensity and global cloud cover. The basis of the idea is in the record of cosmogenic isotopes preserved in ice cores. A well known correlation of isotopes of beryllium and carbon and global temperature reconstruction over more than a thousand years. Hence the link between heliospheric modulated cosmic rays and climate. The best correlation is with a 10 year lag. The most likely connection is through ionisation of aerosols and subsequent growth of cloud condensation nuclei. The core of the science is pretty solid and widely accepted as the dominant cause of climate change prior to 1975. We are only quibbling about a supposed divergence of trends post 1975. Neutron counts peaked in 1991. Usoskin calculated a cosmic ray modulation parameter which peaked strongly in 1991. Cloud cover peaked in 1998. Global surface temperature peaked in 1998. Ocean temperatures are falling or at least steady in the ARGO data. Usoskin et al - Heliospheric modulation of cosmic rays: Monthly reconstruction for 1951–2004 http://cosmicrays.oulu.fi/phi/2005JA011250.pdf I have referenced CERN, the Hadley Centre, the Max Planck Institute and the Sodankyla Geophysical Observatory. There is nothing dubious about the science. The only question is by how much cosmic rays influenced climate in the late 20th century.

Philippe Chantreau at 04:45 AM on 11 July 2009

Climate time lag
A question for Chris, since I could not read through that paper: does "an increase in ionization by a factor of 10" correspond to what happens in nature?

Philippe Chantreau at 04:42 AM on 11 July 2009

Climate time lag
The CRF-cloud relation is not at all so obvious as "skeptics" like to claim. Chris' point about the lack of cyclic variations in phase with solar cycle is a major hurdle in pursuing that hypothesis. Sawhnet, would you expect anything not in defense of his pet theory on Shaviv's personal blog? Any blog post including these words "many in the climate community try to do their best to disregard the evidence" is going to be met with great skepticism by me. I'm sure that, as a self proclaimed skeptic, you can understand.

shawnhet at 01:58 AM on 11 July 2009

Climate time lag
Chris, can you post the material pertaining to the "20-1500 times realistic true atmospheric levels" you mention above? The only link to the paper I have found is behind a pay wall. I find this interpretation odd, because it seems to contradict earlier work by the some of the same authors see here - http://adsabs.harvard.edu/abs/2006cosp...36.2889P where they claim that the levels of SO2 ozone and WV are atmospherically relevant. Further, just for people's information, here is a very good discussion on the state of play of the cosmic ray hypothesis IMO. http://www.sciencebits.com/SloanAndWolfendale "One last point. Although many in the climate community try to do their best to disregard the evidence, there is a large solar-climate link, whether on the 11-year solar cycle (e.g., global temperature variations of 0.1°C), or on longer time scales. Currently, the cosmic-ray climate link is the only known mechanism which can explain the large size of the link, not to mention that independent CRF variations were shown to have climatic effects as well. As James Whitcomb Riley supposedly once said: "If it walks like a duck and quacks like a duck, I would call it a duck"." Cheers, :)

thingadonta at 23:15 PM on 10 July 2009

The CO2/Temperature correlation over the 20th Century
re 61: pretty good post. I think clouds are the key, they will enhance solar increases signficantly. Also your point: "The idea that sulphur dioxide masked warming between the mid 1940’s and 1975 isn’t realistic as the GISS calculated net forcing is positive other than in episodic (and short lived) periods of volcanic perturbation" Another problem with the aerosol idea ~1950-1980 is that they contradict what actually happened in the USA/Europe where they were being emitted between 1950-1980-these were the same areas where surface T increased mostly in the 20th Century...

thingadonta at 22:57 PM on 10 July 2009

Climate time lag
Nice reply, I need to do more research here, I only note that clouds are weird, and also point out that any small global changes in cloud cover would have VERY strong forcings-you can observe this on any cloudy/foggy morning. Note also that the sun 'burning' off low clouds (like burning off fog), even if only a small amount- is hardly mentioned by most reseachers (think Europe in the middle ages compared to today-look at the Dutch 17th Century paintings!). Cloud 'forcings' would be large, and could be strong enough to explain T changes in the 20th century- IF they respond to small changes in solar activity etc, but I note that heat T lags are not mentioned by the Danish scientists etc.

Robbo the Yobbo at 21:03 PM on 10 July 2009

The CO2/Temperature correlation over the 20th Century
Usoskin correlated cosmogenic isotopes of beryllium and carbon with a global temperature reconstruction and found the best fit with a 10 year lag. The isotopes are formed when hit by cosmic radiation which is modulated by heliospheric magnetic intensity. The likely connection of cosmic rays to climate is in ionisation of aerosols in the atmosphere and subsequent growth of cloud condensation nuclei. Heliospheric magnetic intensity peaked late last century on at least a thousand year high – in fact, as Usoskin shows, a very similar hockey stick shape as temperature. With the appropriate bends for the medieval warm period and the little ice age. Usoskin’s data stopped in 1975 – but the comment was made that global temperature and heliospheric modulation of cosmic rays diverged after 1975 and this has been repeated ad nauseum. Usoskin makes a more measured contribution to this latter discussion here: Usoskin et al - Heliospheric modulation of cosmic rays: Monthly reconstruction for 1951–2004 http://cosmicrays.oulu.fi/phi/2005JA011250.pdf The cosmic ray modulation parameter is shown to peak around 1991 and this is entirely consistent with global temperature and cloud parameters. The idea that sulphur dioxide masked warming between the mid 1940’s and 1975 isn’t realistic as the GISS calculated net forcing is positive other than in episodic (and short lived) periods of volcanic perturbation. The cooling is especially evident in the Artic temperature record. The Pacific Decadal Oscillation is a clue to the underlying cause of mid century cooling. The cool period of the PDO extended from the 1946 to 1975 but could a tiny cool spot in the north eastern Pacific affect global temperature so dramatically? Hardly likely. The PDO is associated with changes in ENSO. Cool modes bring more intense and frequent La Niña and warm modes more frequent and intense El Niño. We can show this with statistical analysis of rainfall records – which was my starting point. However, I doubt that even that is much of a multi decadal cooling influence. Instead, I believe the 20 to 30 year PDO is an effect rather than a cause. The heliospheric link to clouds appears to be firmly based in science and the heliosphere varies on a 22 year solar magnetic polar reversal cycle. The polar magnetic reversal occurs in the 11 year solar cycle about 2 years after solar maximum. There is an 11 year period of higher magnetic intensity followed by 11 years of reduced magnetic intensity. This is obviously a thought in progress – I think I need another 20 years of data. Nonetheless, I am working on the assumption that there is actual shortwave heating and cooling of the world ocean on 20 to 30 years cycles. There is a balance between the resistance of a warm surface layer to the penetration of cold subsurface currents and this is particularly apparent in the sweet spot in the north eastern Pacific. A little cooling and cold water upwells strongly. A little warming and it is suppressed. The same heating and cooling happens in the central Pacific with a 2 to 7 year ENSO cycle superimposed. The shortwave heating and cooling shows up in International Satellite Cloud Climatology Project records. Declining cloud cover from the start of records in 1984 to 1998 and about 4W/m2 additional shortwave radiation at the surface. Increasing cloud cover from 1999 to 2008 and about 2 W/m2 less shortwave radiation. The PDO was originally defined in terms of fisheries productivity associated with sea surface temperature changes. Upwelling cold and nutrient rich water in a cool mode provides a huge boost to fisheries and the reverse happens in a warm mode. The biological indicators suggest that the current cool mode commenced after 1999. There’s at least three linked sceptical arguments and one that is totally original – heard here first. Surely, I get sceptic of the week? Cheers Robbo

chris at 19:48 PM on 10 July 2009

Climate time lag
re #15 thingadonta The "chilling stars" Danish scientists certainly don't consider that there is a lag between solar effects and the cloud/climate response. There are three very significant problems with your argument. For example, have a look at the web article on the website of the Danish scientists here: www.spacecenter.dk/publications/scientific-report.../Scient_No._3.pdf If you look at Figure 1 and 2 (especially 2b) you'll see that the Danish scientists attempt to define correlations between solar parameters (they use the cosmix ray flux-CRF, but since all the solar parameters cycle in phase with the solar cycle, this could be solar irradiance or whatever). Are there "lags" in the solar/temperature response demonstrated by these authors? No. They attempt to show that the CRF matches the temperature response effectively with zero lag. The second problem relates to the solar-cloud link. This is normally made in relation to the hypothesis that variations in the cosmic ray flux (CRF) modulated by the solar variation, results in changes in low level clouds. The idea is that the cosmic rays nucleate cloud formation, such that a high CRF (bottom of solar cycle) leads to lots of clouds (and vice versa). Again, the cloud nucleation effect is essentially instantaneous [***]. No lag in cloud levels expected, and there should be a minimal lag in the onset of the temperature response , especially in the atmosphere. The third problem relates to cloud formation. Although the CRF proponents seem to be attempting to insinuate that tiny secular changes of a few percent have altered cloud levels (and this earth temperature) in a significant manner throughout the latter part of the 20th century, they leave unspoken a rather fatal flaw in their analysis. While the secular long term CRF variation since the onset of detailed measures (1958) has been negligible (see Figure 2 of the Svensmark-Friis-Christensen web report I urled above), the variation of the CRF within the solar cycle is very large indeed...it can be up to 25%. Therefore if changes in the CRF dramatically influence low level clouds in a climatically-meaningful manner there should be large and obvious cyclic changes in the cloud levels as the solar cycle waxes and wanes.... ...except that there aren't: http://isccp.giss.nasa.gov/climanal1.html ............................................. [***] Svensmark has recently published his data on cloud nucleation by gamma rays in a model system containing atmospheric pollutants (SO2 and ozone). He had to use very high aerosol concentrations (20-1500 times realistic true atmospheric levels) in order to detect nucleation with his particle detector. Nevertheless, the nucleation occured rapidly (max nucleation within 10 minutes of onset of iradiation). There we don't expect a lag between CRF changes and changes in nucleation events leading to putative cloud formation in the atmosphere, even if cloud formation itself may take some time (minutes/hours) to arise from nucleation. MB Enghoff, JOP Pedersen, T Bondo†, MS Johnson, S Paling and H Svensmark (2008) Evidence for the Role of Ions in Aerosol Nucleation J. Phys. Chem. B 112, 10305–10309 abstract: Aerosol nucleation has been studied experimentally in purified, atmospheric air, containing trace amounts of water vapor, ozone, and sulfur dioxide. The results are compared with model calculations. It is found that an increase in ionization by a factor of 10 increases the production rate of stable clusters by a factor of 3, probably due to ion-induced nucleation.

chris at 17:44 PM on 10 July 2009

Does ocean cooling disprove global warming?
re #51 It's the data that Svensmark and Friis-Christensen present, Rob, and not their interpretation. One should address the data in a paper before considering the reliability of what the authors say. They show very clearly in their Figure 2B their consideration of the CRF since 1958. There is virtually zero secular trend over this period (a slight cooling contribution, if anything). Are you suggesting they don't believe their own data presented in the figures they prepare and present? If the stongest advocates of the CRF-cloud-climate connection show there has been zero CRF contribution to any cloud-climate secular variation (outwith the solar cycle), then one can hardly try to sneak a CRF-cloud-climate connection for the very large late 20th century and contemporary warming in by the back door! The CRF data in the Jasper Kirby article is more or less the same. I don't think there is anything controversial about that. Incidentally, the Svensmark-Friis-Christensen is another of those examples of dismal science from a small sub set of the proponents of the CRF-climate "link". They totally misinterpret the Lockwood-Frolich paper, which nowhere stated nor inferred that the "historical link between the sun and the climate came to an end about 20 years ago". Lockwood and Frolich (proper solar scientists) showed that all of the measurable solar parameters were in the wrong direction for warming since around the mid-late 1980's. The point is that the CRF simply hasn't undergone any trend during the period in which it has been monitored in detail, that could have made any significant contribution to the very marked warming of the last 30-odd years (a secular trend of only a few % according to Jasper Kirby in the web paper you brought to our attention). This is a severe problem for those who assert a strong CRF-cloud-radiative forcing connection, since during the solar cycle the CRF can vary by up to 25% (see Svnsmark-Friis-Christensen Figure 2). Clearly if virtually zero long term change in the CRF can influence the cloud coverage in a way that you seem to be inferring (and Jason Kirby makes a bit of an inference in that direction too, without coming right out and stating this - see page 7/8 of his article), the CRF-cloud link must be exquisitely sensitive. Why then if we inspect the albedo-cloud-moonshine data in the Palle and Goode articles we have been discussing, do we see no cyclical variation of cloud/albedo/moonshine through the solar cycle with its very large changes in CRF? Even your blind Freddy (poor chap!) would consider that a rather problematic flaw in the dodgy CRF-cloud-climate notion.

thingadonta at 16:43 PM on 10 July 2009

The CO2/Temperature correlation over the 20th Century
re50: "that no environmental concern must ever get in the way of, hell, must never even pause, neoconservative laissez faire unregulated capitalism for the very rich - and therefore no fact can ever demonstrate the failure of their ideology"... Yawn. I suppose radical socialist-intellectuals have a completely rosy record?? Did it ever occur to you that bureaucrats and intellectuals can have self-serving interests/bias? Who regulates the regulators?? (Note: Karl Marx scoffed at the idea that the new 'factory managers' could be tempted to distort/exploit the system for their own benefits. What naivety). The question is not left versus right, or market forces versus socialist ideology and/or regulation, but a breakdown in regulation/uncertainties in modelling/ideology in human thought (ie on both 'sides'). If you want historical examples of where intellectualism and modelling/ideology can go drastically wrong (on both 'sides'): - Richard Pipes of Harvard blames radical academics for providing the foundation, framework and justfication for radical Bolshevic communism in the late 19th century-early 20th century. -Weikart blames German Social Darwinists and intellectuals in the late 19th-early 20th century for providing the foundation, framework and justification for radical Nazism -Social Darwinists/Eugenics movement came from within radical academics and intellectuals, who also attempted to impose their 'science model' on the world in the early 20th century (with Nazism as an offshoot of this). -The financial crisis of 2000s, where the 'expert banks' and their modellers got it all wrong. -Human-induced global warming modellers, (>90% sure that there is >90% effect from human activity). The jury is still out on the last one, but their general manner and methods, in my opinion, are not all that dissimilar to the previous ones. AGW just could be a form of socialist-determinism-the bane of the 20th century-eg in biology and ethics (eugenics), radical socialism (communism), Nazism (biology and race), AGW (?socialist-determinist distortion and control of energy?)

thingadonta at 16:20 PM on 10 July 2009

Climate time lag
Another issue about time lags and solar changes: it isn't only solar irradiance that causes T on earth to warm, less low cloud cover is one example which would magnify a slight solar radiation increase. Your data seems to contradict that of Danish solar scientists (eg the book 'the Chilling Stars'), which state that total solar effects peaked in 1985, not the mid 20th centuy. In cold-temperate climates, a slight increase in solar irradiance most significantly reduces cloud cover, as the sun 'burns off' low clouds (just like early morning fog- but only when condensation points are already close to T already-ie in cold-temperate climes), however in tropical climes a slight increase in T/solar irradiance may increase overall cloud cover (the process is not linear). This effect would cause surface T in temperate climates (eg USA/Europe)to rise more than tropical climates, which is also what is observed. The troposphere mostly above ? the reduced low cloud cover shouldnt heat much?, which is also what is observed. Note also, that once low clouds pass their condensation point, they disappear very quickly (ie a tipping point), which would produce a sharp spike in T, and this is not a linear, smooth process-the same as on a cold morning fog, once it has gone. As for time lags, the cold-temperate oceans, with less cloud cover (following a slight rise in T), would heat slower than the land. Whether or not the clouds in tmerpate zones would take time (ie years-decades) to 'burn off' is another possible T lag. I also note that paintings in the 'litle ice age' are generally more cloudy than modern european climates. Danish solar scientists state that solar effects peaked in 1985, not the 1950s (including ?cosmic rays, ?clouds, ?solar magnetics), and with a heat time lag of ~10 years, would bring a peak in the mid-late 1990s, which is also what is observed. And what about solar magnetic field, and cosmic rays. Solar irradiance is not the only solar effect, and non-linear effects may account for recent warming trends. T has now flattened since ~2003, and the worlds governments are going to look pretty silly when T doesnt rise onver the next 10-20vyears, since solar activity has now waned, and c02 does hardly anything at all.

JCLadybug at 13:38 PM on 10 July 2009

The CO2/Temperature correlation over the 20th Century
Question. So I know from the Calvin cycle and from the relative pH of water that as temperatures warm up they CAUSE carbon dioxide levels to increase. Isn't it a circular argument to say that inverse. Wouldn't the temperatures just simply continue to increase if both statements are true?

JCLadybug at 13:17 PM on 10 July 2009

Thumb at 12:59 PM on 10 July 2009

The CO2/Temperature correlation over the 20th Century
"It's up to you to prove that it is warming" Have you been watching the Arctic or Greenland? What about glacier retreat in general, or the rising ocean levels? I thought the new argument was that the Earth was warming but it's not our fault. Now the argument is, in spite of the events I listed above, that the earth is cooling because it's not warming in a straight linear progression since it's peak in 1998? Or is it that it's warming but it's all a big multi-decades long lag effect from the sun? It's really tough to keep up sometimes.

Robbo the Yobbo at 12:46 PM on 10 July 2009

Does ocean cooling disprove global warming?
On nett climate effects from clouds - it is indeterminate - but simply to discount the SW effect by assuming no nett effects is less than scientific. There is a beautiful new site at: http://www.climate4you.com/ClimateAndClouds.htm It is worth checking the entire site. It provides nice pictures and graphs on all sorts of things - including low cloud and high clouds from the ISCCP. It shows tropical high level cloud increasing since 1999 and low level cloud decreasing. This should be a warming from IR trapping by clouds which offsets the increase in shortwave radiation at the surface. Nonetheless, it is obvious to blind Freddy that the planet is not warming all that quickly and that there are changes in the radiative budget caused by cloud changes that need to be accounted for. The position of the IPCC in regarding clouds as a climate feedback rather than a forcing is untenable.

Robbo the Yobbo at 11:20 AM on 10 July 2009

Does ocean cooling disprove global warming?
Posted in the wrong spot - Doh! Never mind, it is still relevant. Just on your Svensmark and Friis-Christensen comment - the paper is not peer reviewed (but you bring it up). I had a quick glance. You are intepreting the discussion in a radically different way from what they themselves say. 'In a recent paper (ref. [1]) Mike Lockwood and Claus Frohlich have argued that recent trends in solar climate forcing have been in the wrong direction to account for "the observed rapid rise in global mean temperatures". These authors accept that "there is considerable evidence for solar influence on Earth's pre-industrial climate and the Sun may well have been a factor in post-industrial climate change in the first half of the last century." But they argue that this historical link between the Sun and climate came to an end about 20 years ago. Here we rebut their argument comprehensively.' You may not agree but you have no right to make an assertion that is diametrically opposed to what is said in very clear terms and then attribute that to the authors.

Robbo the Yobbo at 11:01 AM on 10 July 2009

Climate time lag
Not trying to hide - Rob or Robert is fine - my laptop was offline and I used a work email in registering and forgot my login details. My mates call me Robbo. The cloud reconstruction is, and I will quote Goode et el 2009, that using 'satellite cloud data and Earth reflectance models, we also show that the decadal scale changes in Earth's reflectance measured by earthshine are reliable, and caused by changes in the properties of clouds rather then any spurious signal, such as changes in the Sun-Earth-Moon geometry.’ It is not just one paper or source however – see Hatzianastassiou et al ‘Global distribution of Earth’s surface shortwave radiation budget’, the Global Energy Balance Archive, the International Satellite Cloud Climatology Project and the Baseline Surface Radiation Network. We saw an increase in surface incident shortwave radiation of 3 to 4 W/m2 between 1984 and 1998 and a decrease of 2-3 W/m2 between 1999 and 2008. These fluxes are climatologically significant. As I say, clouds have been treated as a climate feedback rather than a climate forcing and this is proving to be a questionable assumption. I have provided references. There is a link to a 42 page summary from CERN’s Jasper Kirkby. It appeared in Surveys in Geophysics 28, 335-375 (Nov 2007) – but is available on the CERN server. There are several references linked to on ScienceBits: http://www.sciencebits.com/CosmicRaysClimate Check out Figure 3 on the site – but of course never relying on a single source. Google Ilya Usoskin who has a dozen relevant studies on his website. Usoskin specialises in correlating cosmogenic isotopes with global temperature reconstructions over 1150 to many thousands of years. There is also a Hadley Centre Technical Note No 62 prepared for the 4AR. Both the Schwartz and Spencer and Braswell papers I referred to as interesting discussions. The Spencer and Braswell paper is more relevant to changing shortwave forcing. But this is about time lag. The Mizimi post adds another element to uncertainty in the TOA fluxes – CERES calibration – on top of cloud changes and early 20th century TSI changes – as well as other changes in Earth albedo – snow and ice, black carbon, land clearing etc. I have trouble accepting PDO data prior to WW2, let alone calculated TOA fluxes to 1880. The uncertainties are far greater than the changes being modelled. If we add to this the more recent ocean cooling. At a very minimum – a lack of heating since 2004. Does that imply a new climate equilibrium has been reached? Hardly, climate is not and never has been in equilibrium which is the fundamental flaw in all of the climate equilibrium models.

Robbo the Yobbo at 10:52 AM on 10 July 2009

Does ocean cooling disprove global warming?
Not trying to hide - Rob or Robert is fine - my laptop was offline and I used a work email in registering and forgot my login details. My mates call me Robbo. The cloud reconstruction is, and I will quote Goode et el 2009, that using 'satellite cloud data and Earth reflectance models, we also show that the decadal scale changes in Earth's reflectance measured by earthshine are reliable, and caused by changes in the properties of clouds rather then any spurious signal, such as changes in the Sun-Earth-Moon geometry.’ It is not just one paper or source however – see Hatzianastassiou et al ‘Global distribution of Earth’s surface shortwave radiation budget’, the Global Energy Balance Archive, the International Satellite Cloud Climatology Project and the Baseline Surface Radiation Network. We saw an increase in surface incident shortwave radiation of 3 to 4 W/m2 between 1984 and 1998 and a decrease of 2-3 W/m2 between 1999 and 2008. These fluxes are climatologically significant. As I say, clouds have been treated as a climate feedback rather than a climate forcing and this is proving to be a questionable assumption. I have provided references. There is a link to a 42 page summary from CERN’s Jasper Kirkby. It appeared in Surveys in Geophysics 28, 335-375 (Nov 2007) – but is available on the CERN server. There are several references linked to on ScienceBits: http://www.sciencebits.com/CosmicRaysClimate Check out Figure 3 on the site – but of course never relying on a single source. Google Ilya Usoskin who has a dozen relevant studies on his website. Usoskin specialises in correlating cosmogenic isotopes with global temperature reconstructions over 1150 to many thousands of years. There is also a Hadley Centre Technical Note No 62 prepared for the 4AR. Both the Schwartz and Spencer and Braswell papers I referred to as interesting discussions. The Spencer and Braswell paper is more relevant to changing shortwave forcing. But this is about time lag. The Mizimi post adds another element to uncertainty in the TOA fluxes – CERES calibration – on top of cloud changes and early 20th century TSI changes – as well as other changes in Earth albedo – snow and ice, black carbon, land clearing etc. I have trouble accepting PDO data prior to WW2, let alone calculated TOA fluxes to 1880. The uncertainties are far greater than the changes being modelled. If we add to this the more recent ocean cooling. At a very minimum – a lack of heating since 2004. Does that imply a new climate equilibrium has been reached? Hardly, climate is not and never has been in equilibrium which is the fundamental flaw in all of the climate equilibrium models.

David Horton at 09:08 AM on 10 July 2009

Climate time lag
#8 Chris - thank you, that makes sense. The more general point I was exploring is that, as is clear on the previous thread, denialists are interpreting "time lag" as meaning some period when change in input (ie from the sun) has no effect at all on global warming until some long time afterwards, 20 - 50 years, when it suddenly warms up. This is to "explain" why global temperatures keep rising, inconveniently, when sun activity is low and falling. That is, the rise now is a delayed reaction to sun activity half a century ago. In fact, as I was trying to tease out with my questions, the "lag" that Hansen (and John Cook) are talking about is just a delay in the full effect of input changes being felt. A change in sun activity does give an instant response, but equilibrium, between the new input and output parameters, is not reached for some time. However a tracking of temperature would still show it rising and falling (if this were the case) with sunspot activity or cosmic rays or whatever deus ex machina mechanism is the denialist talking point of the day. It doesn't, it rises, and rises, and rises, with GHG concentration, and time is running out. It is I suppose another example of where climatologists need to be very careful of the terminology they use. But it is impossible to guard against the cherry picking of words and sentences and gotcha moments that is the antithesis of science.

canbanjo at 08:15 AM on 10 July 2009

Climate time lag
re the 'radiation at the top of the atmosphere' graph, why do all the runs correlate very closely during the 'dip' periods, compared to the more typical periods?

chris at 07:07 AM on 10 July 2009

Climate time lag
re #5 David, I think I can answer your point #1. First of all we need to define what we mean by lag. This is the period during which the climate response to a change in forcing comes to equilibrium with the forcing. So if we double atmospheric CO2 and the climate responds with a 3 oC rise in temperature, the lag refers to the time for the full 3 oC of warming to be realised. This "evolution" to a new equilibrium occurs on many different time scales. The atmosphere will respond quite quickly...the oceans very slowly. In reponse to a large volcanic eruption there is a rapid onset and very short duration (18-24 months) "pulse" of considerably reduced radiative forcing. The atmosphere will cool quite quickly and this will be quite noticable in land/ocean surface temperature measures. The oceans will statrt to cool. However they will not have "got very far" in cooling before the atmospheric aerosols are washed out of the upper atmosphere and the radiative forcing has returned to the pre-eruption level. So basically in a volcanic eruption the effects of the forcing doesn't penetrate very deeply into the "climate system". Only the superficial levels with rapid response times (the atmosphere) are significantly affected. Although it gets a bit colder in the year or two following a large volcanic eruption, this degree of cooling is small compared to the cooling that would occur if the negative forcing was maintained for a long enough period (hundreds of years) for the ocean heat content to come to equilibrium with the reduced forcing...

chris at 06:55 AM on 10 July 2009

Climate time lag
re #3 Robert ("Robbie" now?), we've already seen on the other thread that there's something rather dodgy about these data. I think we need to wait until the practitioners sort out their methodologies and analyses before we can take the cloud/albedo data seriously. It's a very difficult topic. Interplanetary Magnetic Field. I'd like you to refer us to a peer-reviewed paper that discusses a mechanism and a quantitative analysis of any IMF/CRF/cloud/climate relationship. It seems to me that with the seeming difficulties in relating the CRF-climate hypothesis to empirical observation, some dubious recourse to the IMF is now being made. Let's see some science please. The Schwartz paper. You've made the same mistake with Schwartz as with Goode and Palle. You haven't noticed that these authors have recvised their work in subsequent publications. Schwartz's original analysis was poor (an arbitrary and ridiculously small time constant deining the inertia in the ocean resonse to radiative forcing), and he published a correction in which he increased the time constant to 10 years (I think) and now comes up with with a climate sensitivity around 2 oC (of warming per doubling of atmospheric CO2): http://www.ecd.bnl.gov/steve/pubs/HeatCapCommentResponse.pdf His ocean inertial time constant is probably still to low (and in any case the ocean response very likely can't be modelled with a single time constant), and making it a bit longer would put his climate sensitivty smack back into the scientific "best estimate" of around 3 oC per doubling of [CO2].

Climate Science Glossary

Term Lookup

Settings

Term Lookup

Settings

Latest Posts

Recent Comments