{"id":412,"date":"2007-03-09T03:57:50","date_gmt":"2007-03-09T08:57:50","guid":{"rendered":"\/?p=412"},"modified":"2007-04-09T11:48:18","modified_gmt":"2007-04-09T16:48:18","slug":"cosmoclimatology-tired-old-arguments-in-new-clothes","status":"publish","type":"post","link":"https:\/\/www.realclimate.org\/index.php\/archives\/2007\/03\/cosmoclimatology-tired-old-arguments-in-new-clothes\/","title":{"rendered":"‘Cosmoclimatology’ – tired old arguments in new clothes ‘Cosmoclimatologia’ – argumentos velhos e ultrapassados em nova roupagem<\/lang_po>"},"content":{"rendered":"
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\"ImageIn a recent issue of the journal Astronomy and Geophysics<\/em><\/a> (A&G), Henrik Svensmark coined a new term: ‘cosmoclimatology’<\/a> . I think ‘cosmoclimatology’ is a good and refreshing name for anything combining our cosmos with our climate. However, all other aspects of the article I found very disappointing. We have already covered most of these topics before, but the A&G articles provides us with some new aspects to discuss. Furthermore, Svensmark is the Director for Center for Sun-Climate Research, Danish National Space Center, and therefore influential. He is also the co-author of a recent book with Nigel Calder<\/a> that received some attention<\/a>. Furthermore, a laboratory experiment<\/a> of his also managed to make some headlines. It seems that solar forcing is one of the sceptics’ last trenches<\/a> in the debate about climate change. In my view the A&G paper therefore merits a comment as long as the same old and worn arguments resurface without discussing misgivings from the critics.<\/p>\n

<\/p>\n

There are a number of issues which really make the A&G paper poor in my view. One is the neglect in addressing old criticisms of the hypothesis that galactic cosmic rays (GCR) change our climate by modulating clouds (see here<\/a>, here<\/a>, & here<\/a>). Svensmark is very vague on the lack of any trend in GCR<\/a> or other solar proxies since 1952. I confronted him about this question on an European Geophysical Society (EGS)<\/em> conference in Nice a few years ago, and have since published a paper<\/a> also making the point. The A&G article makes selective references, without answering the serious criticism forwarded by Damon & Laut (2004)<\/a>, Laut (2003)<\/a>, or myself<\/a>. To be fair, the critical paper by Kristjansson and Kristiansen (2000)<\/a> is cited, albeit only to say that Svensmarks’s own conclusion is “a counter-intuitive finding for some critics<\/em>“. The remaining treatment of critical aspects is completed in the A&G article without further qualifications other than the following passage (my emphasis): <\/p>\n

The chief objection to the idea that cosmic rays influence cloudiness came from meteorologists<\/em> who insisted that there was no mechanism by which they could do so. On the other hand, some atmospheric physicists<\/em> concluded that observation and theory had failed to account satisfactorily for the origin of aerosol particles without which water is unable is unable to condense to make clouds.<\/p><\/blockquote>\n

I don’t think this is meant as a joke, and I don’t know if the article tries to make a point about classifying critics and supporters of his ideas as ‘meteorologists’ and ‘physicists’ (I’m a physicist). But that’s a tiny detail compared to the more substantial misconceptions embedded in this passage. There are plenty of ‘seeds’ in the air on which water can form, also known as cloud condensation nuclei<\/a> (CCN). According to my old text book ‘A Short Course in Cloud Physics’ by Rogers and Yau (1989, p. 95 in Third edition)<\/a>: “Condensation nuclei of some sort are always present in the atmosphere in ample numbers: clouds form whenever there are vertical air motions and sufficient moisture”. The CCN tend to consist of mineral dust, sea salt, or sulphur-based matter. <\/p>\n

I have serious misgivings concerning the following – vague yet false – statement put forward in the A&G article :<\/p>\n

Attempts to show that certain details in the climatic record confirm the greenhouse forcing (e.g. Mitchell et al.<\/em>, 2001) have been less conclusive. By contrast, the hypothesis that changes in cloudiness obedient to cosmic rays help to force climate change predicts a distinctive signal that is in fact very easily observed, as an exception that proves the rule.<\/p><\/blockquote>\n

Again, no further qualifications or references. The irony is that Svensmark ignores (in addition to the lack of trend in GCR) the fact that the night-time temperature has risen faster than the day-time temperature, which I did pester him about on a Nordic Meteorology Meeting<\/em> in Copenhagen in 2002. A journalist from Jyllands Posten<\/em> present at the conference got the message, as my criticism was echoed in a news report the following day (“Klimaforskere i \u00e5ben krig” [translation ‘Climate researchers in open war’]<\/em>, May 28, 2002): It’s tricky to explain how a warming caused by decreasing albedo would be stronger at the night-side (dark) of the planet.<\/p>\n

Another newer puzzle is the surprisingly good correlation between low clouds and GCR (se figure below), since higher clouds<\/a> (global mean cover ~13%) or middle clouds<\/a> (~20%) which are not influenced by GCR, mask the lower ones<\/a> (which represents between 28% and 30% of the globe). It’s indeed a surprisingly good fit between the two curves in the A&G article (reproduced below), considering the time structure of both the high-cloud, middle-cloud, and low-cloud curves, and the satellites cannot see the low-level clouds where there are higher clouds above blocking the view. The fact that the variations are small (~1% amplitude!) compared to the total area, suggest that the overlap\/masking effect by the higher cloud must be very small for a high correlation to shine through the upper clouds. Even if the clouds hypothetically were completely determined by GCR, one would expect to see deterioration of the correlation if viewed from above due to the presence of higher clouds not influenced by GCR. Another issue is that the cloud data used in this analysis was only based on the infra-red (IR) channel, and a better analysis would include the visible observations too, but if the visible data are included, then the correlation is lower (private communications, J\u00f8rn Kristjansen). <\/p>\n

\"Extracts<\/a><\/p>\n

On a more technical note, there seems to be inconsistencies between the GCR presented in Fig 2 and 3 in the A&G article (see red circles in the plot above), and this is not explained in the article. In Fig. 3 (left panel above) the GCR count increases by 10% but the maximum value is about 0% in Fig. 2 (right panel above), and the minimum value is abut -18% in Fig 3 but only -13% in Fig 2. It seems as if Fig 2 & 3 were based on different data sources. To be fair, both GCR and ISCCP are continuously updated and revised. But I am surprised that routine update and revision would result in as large differences as seen here. It looks as if the curve has been readjusted at some stage, but it is then a bit strange that the curve representing the global lower cloud cover doesn’t seem to have been re-scaled: the difference between maximum and minimum is about 3% in both figures (it’s annoying that the vertical axis for the cloud cover are given in different units in Fig.2 & 3). Is this important? I don’t know. But it could be a sign of sloppy work. There is not sufficient information about methodology that I could repeat the results presented here. <\/p>\n

\"The<\/a>\"Low<\/a><\/p>\n

Svensmark must have adjusted the cloud data<\/a> too. Shown below is a figure from a previous paper where he justified an adjustment from a break in the difference between low and high clouds. The question is: why would the error be in the lower cloud measurements and not the high clouds? I haven’t seen any other independent statements about breaks or problems<\/a> in the data series for low clouds after ~1995. Apparently, there are some biases in the ISCCP data, and Stordal et al. (2005) <\/a> suggest that there is a spurious “footprint” from METEOSAT imprinted on the high (cirrus) clouds, and the problems with the ISCCP trends are now becoming well known<\/a>. Besides, the fundamental error Marsh and Svensmark made in their ‘correction’ has discussed before<\/a>, but since this issue keeps re-appearing, the ‘adjustment’ is shown again (left) while the ‘adjustment’ cannot be discerned in independent plots of the most recent data (right, and a second opinion sought in an independent analysis by K. Gislefoss<\/a>). <\/p>\n

In the A&G article, GCRs get the blame for the ‘snowball earth<\/a>‘ episodes, and Svensmark writes: <\/p>\n

A surprising by-product of this line of enquiry is a new perspective on changing fortunes of life over 3.5 billion years ago. <\/p><\/blockquote>\n

\"Extract Furthermore, the paper claims to explain the ‘faint sun paradox<\/a>‘, by the complete absence of low clouds because there were allegedly no GCR at the time. Presumably, it is seriously meant. Proposing that the GCR is the only factor affecting low clouds, is inconsistent with the result shown in his very own Fig. 4 (the scatter plot shown left). In the A&G article, Fig 4 doesn’t really show the relationship between GCR and clouds, but between ion density and numbers of ultra-small<\/em> (radius greater than 3 nano-meters) aerosol nucleation. The large scatter suggests that the number of ultra-small aerosols is fairly weakly affected by the number of ions – otherwise all the points would lie close to the diagonal line. This implies that other factors must influence the formation of ultra-small aerosols in addition to some effect due to ionization. And this is only in the laboratory environment – on the outside of Svensmark’s test chamber, more factors may play a role. <\/p>\n

In the laboratory experiment ‘SKY’, UV-light was modulated to mimic the variations in the Sun, but it is not clear whether the effects observed due to changes in the UV are transferable to GCR. The experiment also involved natural GCR (as opposed to a particle beam which presumably would be easier to control), supplemented with gamma rays. Then the aerosols were according to the article stable ultra-small clusters of sulphuric acid. So, what about the larger aerosols which play a role in cloud formation? According to “Atmospheric particles and nuclei” by Götz et al. (1991)<\/a>, Junge (1963)<\/a> proposed on the basis of aerosol measurements that ‘large’ and ‘giant’ particles (radius greater than 0.1 micro-meter) constitute the majority of CCN, independently of their chemical composition. Besides, the Köhler curve<\/a> (also see here<\/a>) based on theoretical work from 1926 and onwards<\/a> indicates that droplets only start to grow spontaneously only the droplet is greater than a critical size (they are then ‘supercritical’). The number of sulphuric aerosols is also influenced by the availability of sulphur in general. The amount of sulphur can vary, e.g. with the combustion of fossil fuels, volcanic eruptions, as well as due to biological activity (i.e. through the emission of dimethyl sulphide, or ‘DMS’; Götz et al. ,1991, p. 108), and presumably the number of sulphuric acid clusters formed over the past billion years can have been affected by several of geological factors. Besides, it is the vapour pressure (or ‘supersaturation’) which really control whether cloud drops or not, seeing as aerosols tend to be around anyway. I also have some general questions regarding isotopic evidence from pre-historic times. Are isotopes from the distance past only<\/em> created by GCR bombarding Earth’s atmosphere or could there be other sources? Could some be introduced by meteorite\/astroid impacts, volcanic activity, or different emission of radon gas from Earth’s interior?<\/p>\n

I would expect the albedo effect presented by clouds to be weak over the mostly snow\/ice covered Antarctica, but Svensmark argues that the clouds here warm rather than cool the temperature. This claim is not quantified. Is he suggesting some GHG-effect kicking in during the Antarctic winters? Is the sense\/chronology of causation really determined? What about temperature affecting the cloudiness (e.g. advection of mild and moist air), and the role of circulation patterns? For sure, there is no simple one-way relationship. I think that the A&G article is bit too cavalier about the complexity involved in the atmospheric processes. The cavalier attitude seems to be a trademark of cosmoclimatology.<\/p>\n

I presume that many celestial bodies and complicated calculation of gravitational pull must make the modelling of the galaxy dynamics difficult, and star formation processes must have altered the distribution of mass and hence the gravitational field. So, surely the dynamics of the stars over billions of years can be characterised as chaotic? Is it really possible to re-construct the constellations and our solar systems trajectory around the galaxy more than 2 billion years ago with a precision which precedes that of calculating the effect of increasing the GHG concentrations at present day? Is the story as simple as the one narrated by Svensmark? He even suggests that his ideas amount to a paradigm<\/em> shift, that ‘scientifically speaking’ is as secure as the prevailing paradigm of AGW. I find this sweeping statement a bit puzzling as no further qualification is made on the matter of AGW. Exactly what are the weak points in the AGW paradigm? I wonder if Svensmark really knows what he talks about. <\/p>\n

It is possible that GCRs do have an effect on climate through the modulation of clouds<\/a>, but I don’t think it is very strong. I also think that Svensmark’s claims are wildly exaggerated, but most of my objection lies in the way the arguments have been presented in this A&G article. I have the impression that the A&G article comes from the same school as “The Skeptical Environmentalist<\/a>“, which also has been criticised for cherry picking references to make mere speculation appear as more solidly founded. To ignore aspects that don’t fit the hypothesis is definitely not<\/strong> science. Neither is adjusting data so to provide a good fit without a solid and convincing justification. Science, however, means objectivity, transparency, repeatability, and in principle the possibility of falsification. Furthermore, it is only a lack of respect for the readers to publish an article that doesn’t provide all relevant sides to the story. I hope that Svensmark reads my comments and responds to them here at RealClimate. I also hope that this is read by scholars and journalists who start asking the critical questions. I do not know the answer to the questions that I pose here, so I’d be interested to hear your view.<\/p>\n

Acknowledgements<\/strong>Thanks to J\u00f8rn Kristiansen for comments and input to my post and Kristian Gislefoss for one figure on global low cloudiness.<\/p>\n

<\/p>\n

\"ImageNuma recente edi\u00e7\u00e3o da Astronomy and Geophysics<\/em><\/a> (A&G), Henrik Svensmark cunhou um novo termo: ‘cosmoclimatologia’.<\/a> Eu acho que ‘cosmoclimatologia’ \u00e9 um nome bom e renovador para qualquer coisa que combine nosso cosmos com nosso clima. Contudo, achei muito desapontador todos os outros aspectos do artigo. J\u00e1 cobrimos a maioria desses t\u00f3picos antes, mas o artigo da A&G nos d\u00e1 alguns novos aspectos para discutir. Al\u00e9m do mais, Svensmark \u00e9 o diretor do Centro de Pesquisa sobre o Sol-Clima, do Centro Nacional Espacial Holand\u00eas, e portanto \u00e9 muito influente. Ele \u00e9 tamb\u00e9m co-autor de um livro recente com Nigel Calder<\/a> que recebeu alguma aten\u00e7\u00e3o<\/a>. Ainda mais, um experimento de laborat\u00f3rio<\/a> seu tamb\u00e9m ganhou notoriedade. Parece que a for\u00e7ante solar \u00e9 uma das\u00faltimas trincheiras<\/a> dos c\u00e9ticos no debate sobre mudan\u00e7as clim\u00e1ticas. Na minha vis\u00e3o, o trabalho da A&G merece ent\u00e3o coment\u00e1rios, dado que os mesmos velhos e ultrapassados argumentos resurgem sem se discutir os temores dos cr\u00edticos. <\/p>\n

Existem algumas quest\u00f5es que tornam o trabalho da A&G realmente pobre ao meu ver. Uma delas \u00e9 a omiss\u00e3o de responder as velhas cr\u00edticas da hip\u00f3tese de que raios c\u00f3smicos gal\u00e1ticos (sigla em ingl\u00eas GCR) mudam nosso clima modulando as nuvens. (veja aqui<\/a>, aqui<\/a> e aqui<\/a>). Svensmark \u00e9 muito vago sobre a falta de tend\u00eancia nos GCR<\/a> ou em outras vari\u00e1veis solares desde 1952. Eu o questionei sobre isso numa confer\u00eancia da Sociedade Europ\u00e9ia de Geof\u00edsica (sigla em ingl\u00eas EGS)<\/em> em Nice h\u00e1 alguns anos atr\u00e1s, e publiquei tamb\u00e9m um trabalho <\/a> sobre esse ponto. O artigo da A&G seleciona as refer\u00eancias, sem no entanto responder as s\u00e9rias cr\u00edticas enchaminhadas por Damon & Laut (2004)<\/a>, Laut (2003)<\/a> e eu
\nmesmo<\/a>. Para ser honesto, o trabalho cr\u00edtico de Kristjansson e Kristiansen (2000)<\/a> \u00e9 citado, embora somente para dizer que a pr\u00f3pria conclus\u00e3o de Svensmark seja “um achado contra-intuitivo para alguns cr\u00edticos<\/em>“. O tratamento restante dos aspectos cr\u00edticos no artigo da A&G \u00e9 sem maiores qualifica\u00e7\u00f5es, a n\u00e3o ser a seguinte passagem (minha \u00eanfase): <\/p>\n

\n

A principal obje\u00e7\u00e3o para a id\u00e9ia de que raios c\u00f3smicos t\u00eam influ\u00eancia na cobertura de nuvens veio de meteorologistas<\/em> os quais insistiram que n\u00e3o haveria mecanismo capaz de produzir isso. Por outro lado, alguns f\u00edsicos<\/em> atmosf\u00e9ricos concluiram que a observa\u00e7\u00e3o e a teoria falharam em considerar satisfatoriamente a origem das part\u00edculas de aeross\u00f3is sem as quais a \u00e1gua n\u00e3o condensa para formar nuvens.<\/p>\n<\/blockquote>\n

Eu n\u00e3o acho que isso seja uma piada, e n\u00e3o sei se o artigo tenta criar uma classifica\u00e7\u00e3o de cr\u00edticos e adeptos de suas id\u00e9ias como ‘meteorologistas’ e ‘f\u00edsicos’ (eu sou f\u00edsico). Mas este \u00e9 um detalhe diminuto comparado com os conceitos errados inclu\u00eddos nessa passagem. Existem muitas ‘sementes’ no ar que podem condensar \u00e1gua, tamb\u00e9m conhecidas como n\u00facleos de condensa\u00e7\u00e3o de nuvens<\/a> (sigla em ingl\u00eas CCN). De acordo com meu velho livro ‘A Short Course in Cloud Physics’ de Rogers
\ne Yau (1989, p. 95, terceira edi\u00e7\u00e3o)<\/a>: “N\u00facleos de condensa\u00e7\u00e3o de algum tipo est\u00e3o sempre presentes na atmosfera em grande n\u00famero: nuvens se formam sempre que h\u00e1 movimentos verticais de ar e suficiente umidade”. Os CCN consistem na maioria das vezes de poeira mineral, sal marinho ou material sulfuroso. <\/p>\n

Eu tenho s\u00e9rias d\u00favidas sobre a seguinte \u2013 vaga ainda que falsa \u2013 afirma\u00e7\u00e3o colocada adiante no artigo da A&G :<\/p>\n

\n

Tentativas de mostrar que certos detalhes nos dados clim\u00e1ticos confirmam a for\u00e7ante de efeito estufa (por exemplo Mitchell et al.<\/em>, 2001) t\u00eam sido menos conclusivas. Em contraste, a hip\u00f3tese de mudan\u00e7as nas nuvens devido aos raios c\u00f3smicos que ajuda a for\u00e7ar uma mudan\u00e7a clim\u00e1tica prev\u00ea um sinal distinto que \u00e9 na verdade muito facilmente observado mais como uma exce\u00e7\u00e3o do que uma regra.<\/p>\n<\/blockquote>\n

De novo, sem mais qualifica\u00e7\u00f5es ou refer\u00eancias. A ironia \u00e9 que Svensmark ignora (al\u00e9m da falta de tend\u00eancia dos GCR) o fato de que as temperaturas noturnas t\u00eam subido mais r\u00e1pido do que as temperaturas diurnas, ponto pelo qual eu o incomodei numa Reuni\u00e3o Nordica de Meteorologia<\/em> em Copenhagen em 2002. Um jornalista do Jyllands Posten<\/em> presente na confer\u00eancia captou a mensagem, de modo que minha cr\u00edtica repercurtiu num jornal no dia seguinte (“Klimaforskere i \u00e5ben krig” [tradu\u00e7\u00e3o ‘Pesquisadores do clima em p\u00e9 de querra]<\/em>, 28 de maio, 2002): \u00c9 dif\u00edcil explicar como um aquecimento causado pela diminui\u00e7\u00e3o do albedo poderia ser mais forte no lado escuro (noite) do planeta.<\/p>\n

Um outro quebra-cabe\u00e7a est\u00e1 na surpreendentemente boa correla\u00e7\u00e3o entre nuvens e GCR (veja figura abaixo), tendo em vista que nuvens altas<\/a> (cobertura m\u00e9dia global de ~13%) ou nuvens
\nintermedi\u00e1rias<\/a> (~20%) que n\u00e3o s\u00e3o influenciadas por GCR, mascaram as nuvens baixas<\/a>
\n(que representam entre 28% e 30% do globo). \u00c9 de fato supreendente o bom ajuste entre as duas curvas no trabalho da A&G (reproduzido abaixo), considerando a estrutura de tempo nas curvas de altas, intermedi\u00e1rias e baixas nuvens, e que os sat\u00e9lites n\u00e3o podem ver as nuvens de baixo n\u00edvel onde acima existem nuvens de n\u00edveis mais altos bloqueando a vis\u00e3o. O fato \u00e9 que as varia\u00e7\u00f5es s\u00e3o pequenas (~1% em amplitude!) comparadas com a \u00e1rea total, sugerindo que o efeito de sobreposi\u00e7\u00e3o\/mascaramento por nuvens altas deve ser muito pequeno para uma alta correla\u00e7\u00e3o acontecer atrav\u00e9s de nuvens elevadas. Mesmo se hipoteticamente as
\nnuvens fossem completamente determinadas por GCR, poder\u00edamos esperar ver uma deteriora\u00e7\u00e3o da correla\u00e7\u00e3o se vista por cima, devido \u00e0 presen\u00e7a de nuvens altas n\u00e3o influenciadas por GCR. Outra quest\u00e3o \u00e9 que os dados de nuvens usados nessa an\u00e1lise foram somente baseados no canal infra-vermelho (sigla em ingl\u00eas IR),
\ne uma melhor an\u00e1lise deveria incluir as observa\u00e7\u00f5es no vis\u00edvel tamb\u00e9m, mas se os dados do vis\u00edvel s\u00e3o inclu\u00eddos, ent\u00e3o a correla\u00e7\u00e3o seria menor (comunica\u00e7\u00e3o pessoal, J\u00f8rn Kristjansen). <\/p>\n

\"<\/a><\/p>\n

Numa nota mais t\u00e9cnica, parece haver inconsist\u00eancias entre o GCR apresentado nas Figuras 2 e 3 do artigo da A&G (veja os c\u00edrculos vermelhos no gr\u00e1fico acima), e isto n\u00e3o \u00e9 explicado no artigo. Na Fig. 3 (gr\u00e1fico da esquerda acima) o GCR aumentou em 10% mas o m\u00e1ximo valor \u00e9 cerca de 0% na Fig. 2 (gr\u00e1fico da
\ndireita acima), e o m\u00ednimo valor \u00e9 aproximadamente de -18% na Fig 3 mas somente -13% na Fig 2. Parece que as Fig 2 & 3 foram baseadas em fontes diferentes de dados. Para ser justo, ambos GCR e ISCCP s\u00e3o continuamente atualizados e revisados. Mas fico surpreso que a rotineira atualiza\u00e7\u00e3o e revis\u00e3o resultem em grandes diferen\u00e7as como vistas aqui. Parece como se a curva tivesse sido reajustada em algum est\u00e1gio, mas \u00e9 ent\u00e3o um pouco estranho que a curva representando a cobertura de nuvens baixas n\u00e3o parece ter sido rescalonada: as diferen\u00e7as entre o m\u00e1ximo e o m\u00ednimo \u00e9 de cerca de 3% e ambas figuras (\u00e9 chato que os eixos verticais para a cobertura de nuvens s\u00e3o dados em unidades diferentes na Fig.2& 3). Ser\u00e1 isso importante? N\u00e3o sei. Mas pode ser um sinal de um trabalho mal feito. N\u00e3o h\u00e1 informa\u00e7\u00e3o suficiente sobre a metodologia para que eu pudesse repetir os resultados apresentados aqui. <\/p>\n

\"Os<\/a>\"Nuvens<\/a><\/p>\n

Svensmark certamente deve ter ajustado os dados de nuvem <\/a> tamb\u00e9m. Acima \u00e9 mostrada uma figura de um artigo anterior no qual ele justifica um ajuste de uma quebra na diferen\u00e7a entre nuvens baixas e altas. A quest\u00e3o \u00e9: por que o erro estaria nas medidas de nuvens baixas e n\u00e3o nas de
\nnuvens altas? Eu n\u00e3o tenho visto quaisquer outras declara\u00e7\u00f5es independentes sobre quebras ou problemas <\/a> na s\u00e9rie de dados para nuvens baixas depois de ~1995.
\nApparentemente, existem algumas tend\u00eancias nos dados do ISCCP, e Stordal et al. (2005) <\/a> sugere que existe uma marca esp\u00faria do METEOSAT impressa nas nuvens altas (cirrus), e os problemas com as tend\u00eancias do ISCCP est\u00e3o agora se tornando bem conhecidas<\/a>. Junto a isso, o erro fundamental que Marsh e Svensmark fizeram em
\nsuas ‘corre\u00e7\u00f5es’ foi j\u00e1
\ndiscutido<\/a>, mas como essa quest\u00e3o continua reaparecendo, o ‘ajuste’ \u00e9 novamente mostrado (esquerda) enquanto que o ‘ajuste’ n\u00e3o pode ser discernido em gr\u00e1ficos independentes nos dados mais recentes (direita, e uma segunda opini\u00e3o vizualizada numa an\u00e1lise independente de K. Gislefoss<\/a>). <\/p>\n

No artigo da A&G article, os GCR seriam respons\u00e1veis pelos epis\u00f3dios de ‘bola de neve da Terra<\/a>‘, e Svensmark escreve: <\/p>\n

\n

Um surpreendente produto dessa linha de questionamento \u00e9 uma nova perspectiva da mudan\u00e7a do destino da vida ao longo dos \u00faltimos 3,5 bilh\u00f5es de anos. <\/p>\n<\/blockquote>\n

\"Extra\u00eddo Al\u00e9m disso, o artigo pretende explicar o ‘paradoxo solar fraco<\/a>‘, pela completa aus\u00eancia de nuvens baixas pois alegadamente n\u00e3o havia nenhum GCR naquele tempo. Presumivelmente, isso \u00e9 levado a s\u00e9rio. Propor que os GCR sejam o \u00fanico fator afetando nuvens baixas \u00e9 inconsistente com o resultado
\nmostrado na muito sua Fig. 4 (a plotagem mostrada \u00e0 esquerda). No artigo da A&G, a Fig 4 realmente n\u00e3o mostra a rela\u00e7\u00e3o entre GCR e nuvens, mas entre densidade i\u00f4nica e os n\u00fameros de ultra-pequenos<\/em> (raio superior a 3 nanometros) aeross\u00f3is de nuclea\u00e7\u00e3o. A grande dispers\u00e3o sugere que o n\u00famero de aeross\u00f3is ultra-pequenos \u00e9 muito fracamente afetado pelo n\u00famero de ions \u2013 do contr\u00e1rio, todos os pontos situariam-se pr\u00f3ximos \u00e0 linha diagonal. Isso implica em outros fatores que devem influenciar a forma\u00e7\u00e3o de aeross\u00f3is em adi\u00e7\u00e3o a algum efeito devido \u00e0 ioniza\u00e7\u00e3o. E isso \u00e9 somente no ambiente de laborat\u00f3rio \u2013 fora da c\u00e2mara de teste de Svensmark mais fatores devem desempenhar algum papel. <\/p>\n

No experimento de laborat\u00f3rio ‘SKY’, a luz UV (ultravioleta) foi modulada para mimetizar a varia\u00e7\u00e3o do sol, mas n\u00e3o ficou claro se os efeitos observados devido \u00e0s mudan\u00e7as no UV podem ser tranferidos aos GCR. O experimento tamb\u00e9m envolveu GCR naturais (em oposi\u00e7\u00e3o a um feixe de part\u00edculas que presumivelmente seria mais f\u00e1cil de controlar), suplementado com raios gama. Os aeross\u00f3is foram, de acordo com o artigo, grupos ultra-pequenos est\u00e1veis de \u00e1cido sulf\u00farico. Ent\u00e3o, o que dizer dos grandes aeross\u00f3is que t\u00eam um papel na forma\u00e7\u00e3o das nuvens? De acordo com “Atmospheric particles and nuclei” de G\u00f6tz
\net al. (1991)<\/a>, Junge (1963)<\/a> prop\u00f4s, baseado em medidas de aeross\u00f3is, que part\u00edculas ‘grandes’ e ‘gigantes’ (raio maior que 0.1 micr\u00f4metro) constituem a maioria dos CCN, independentemente de sua composi\u00e7\u00e3o qu\u00edmica. Ao lado disso, a curva
\nde K\u00f6hler <\/a> (veja tamb\u00e9m aqui<\/a>) baseada no trabalho te\u00f3rico de 1926 e adiante<\/a> indica que as gotas somente come\u00e7am a crescer espontaneamente a partir de um certo tamanho cr\u00edtico (elas s\u00e3o todas ‘supercr\u00edticas’). O n\u00famero de aeross\u00f3is sulf\u00faricos \u00e9 tamb\u00e9m influenciado pela disponibilidade de enxofre em geral. A quantidade de enxofre pode variar, por exemplo, com a queima de combust\u00edveis f\u00f3sseis, erup\u00e7\u00f5es vulc\u00e2nicas, bem como devido \u00e0 atividade biol\u00f3gica (i.e. atrav\u00e9s da emiss\u00e3o de dimetil sulfito ou ‘DMS’; G\u00f6tz et al. ,1991, p. 108), e presumivelmente o n\u00famero de grupos de \u00e1cido sulf\u00farico formado nos \u00faltimos bilh\u00f5es de anos pode ter sido afetado por diversos fatores geol\u00f3gicos. Aliado a isso, a press\u00e3o de vapor (ou ‘supersatura\u00e7\u00e3o’) deve realmente controlar se uma nuvem forma gotas ou n\u00e3o, visto que os aeross\u00f3is tendem estar casualmente ao redor. Tenho tamb\u00e9m algumas quest\u00f5es gerais sobre as evid\u00eancias isot\u00f3picas de tempos pr\u00e9-hist\u00f3ricos. Seriam os is\u00f3topos de tempos passados criados somente<\/em> por GCR bombardeando a atmosfera terrestre ou poderiam haver outras fontes? Algumas poderiam ser introduzidas por impactos de meteoritos\/aster\u00f3ides, atividades vulc\u00e2nicas ou emiss\u00e3o distinta de g\u00e1s rad\u00f4nio originado no interior da Terra?<\/p>\n

Eu esperaria um fraco efeito do albedo das nuvens sobre as regi\u00f5es cobertas de neve\/gelo da Antarctica, mas Svensmark argumenta que a temperatura das nuvens aumentaria (esquentaria) ao inv\u00e9s de diminuir (resfriar). Esta declara\u00e7\u00e3o n\u00e3o \u00e9 quantificada. Estar\u00e1 ele sugerindo algum efeito de gas de efeito estufa atuando durante os invernos Ant\u00e1rticos? Estaria o senso\/cronologia de causa realmente determinado? O que dizer da temperatura afetando a cobertura de nuvens (por exemplo por advec\u00e7\u00e3o de ar suave e \u00famido) e o papel dos padr\u00f5es de circula\u00e7\u00e3o? Certamente n\u00e3o h\u00e1 uma simples rela\u00e7\u00e3o unidirecional. Acho que o artigo da A&G seja um pouco displicente sobre a complexidade envolvida nos processos atmosf\u00e9ricos. Essa atitude displicente parece ser uma marca registrada da cosmoclimatologia.<\/p>\n

Presumo que muitos corpos celestes e c\u00e1lculos complicados de gravita\u00e7\u00e3o tornam a modelagem da din\u00e2mica de gal\u00e1xias muito dif\u00edcil, e os processos de forma\u00e7\u00e3o de estrelas devem ter alterado a distribui\u00e7\u00e3o de massa e, assim, do campo gravitacional. Ent\u00e3o, a din\u00e2mica de estrelas durante bilh\u00f5es de anos poderia ser certamente caracterizada como sendo ca\u00f3tica? Ser\u00e1 mesmo poss\u00edvel reconstruir as constela\u00e7\u00f5es e a trajet\u00f3ria de nosso sistema solar ao redor da gal\u00e1xia h\u00e1 mais de 2 bilh\u00f5es de anos atr\u00e1s com uma precis\u00e3o que precede aquela
\nde calcular o efeito do aumento da concentra\u00e7\u00e3o de gases de efeito estufa nos dias atuais? Ser\u00e1 a est\u00f3ria t\u00e3o simples quanto narrada por Svensmark? Ele mesmo sugere que suas id\u00e9ias s\u00e3o uma mudan\u00e7a de paradigma<\/em>, o que ‘cientificamente falando’ seja t\u00e3o seguro quanto a preval\u00eancia do paradigma do
\naquecimento global antropog\u00eanico (sigla em ingl\u00eas, AGW). Eu vejo essa extensa declara\u00e7\u00e3o um pouco nebulosa dado que nenhuma qualifica\u00e7\u00e3o seja feita sobre a quest\u00e3o AGW. Quais seriam exatamente os pontos fracos do paradigma AGW? Me pergunto se Svensmark sabe do que est\u00e1 falando. <\/p>\n

\u00c9 poss\u00edvel que os GCR de fato apresentem um efeito sobre o clima atrav\u00e9s da modula\u00e7\u00e3o das nuvens<\/a>, mas eu n\u00e3o creio que seja muito forte. Tamb\u00e9m penso que as declara\u00e7\u00f5es de Svensmark s\u00e3o muito exageradas, mas em geral minhas obje\u00e7\u00f5es situam-se na forma como os argumentos s\u00e3o apresentados no artigo da A&G. Tenho a impress\u00e3o que o trabalho da A&G vem da mesma escola do “O Ambientalista C\u00e9tico <\/a>“, que tamb\u00e9m tem sido criticado por refer\u00eancias pontualmente escolhidas para tornar mera especula\u00e7\u00e3o como solidamente fundamentada. Ignorar aspectos que n\u00e3o se adequam a hip\u00f3tese n\u00e3o
\n<\/strong> \u00e9 ci\u00eancia definitivamente. Do mesmo modo n\u00e3o \u00e9 ajustar os dados de modo a dar um bom resultado sem uma s\u00f3lida e convincente justificativa. A Ci\u00eancia, todavia, significa objetividade, transpar\u00eancia, repitabilidade, e em princ\u00edpio a possibilidade de falsifica\u00e7\u00e3o. Al\u00e9m disso, seria somente uma falta de respeito com os leitores publicar um artigo que n\u00e3o contemple todos os lados relevantes da est\u00f3ria. Espero que Svensmark leia meus comet\u00e1rios e os responda aqui no RealClimate. Tamb\u00e9m espero que isso tudo seja lido por alunos e jornalistas que iniciam perguntas das quest\u00f5es cr\u00edticas. N\u00e3o sei a resposta para essas quest\u00f5es que postei aqui, assim gostaria de saber suas vis\u00f5es.<\/p>\n

Agradecimentos
\n<\/strong>Agrade\u00e7o J\u00f8rn Kristiansen pelos coment\u00e1rios e contribui\u00e7\u00f5es para essa minha postagem e Kristian Gislefoss por uma figura global da cobertura de baixas nuvens.<\/p>\n

traduzido por Ivan B. T. Lima e Fernando M. Ramos<\/a> <\/small><\/p>\n<\/p>\n

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In a recent issue of the journal Astronomy and Geophysics (A&G), Henrik Svensmark coined a new term: ‘cosmoclimatology’ . I think ‘cosmoclimatology’ is a good and refreshing name for anything combining our cosmos with our climate. However, all other aspects of the article I found very disappointing. We have already covered most of these topics […]<\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[1,4],"tags":[],"class_list":{"0":"post-412","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-climate-science","7":"category-sun-earth-connections","8":"entry"},"aioseo_notices":[],"post_mailing_queue_ids":[],"_links":{"self":[{"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/posts\/412","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/users\/11"}],"replies":[{"embeddable":true,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/comments?post=412"}],"version-history":[{"count":0,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/posts\/412\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/media?parent=412"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/categories?post=412"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.realclimate.org\/index.php\/wp-json\/wp\/v2\/tags?post=412"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}