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Sun-earth connections

Peer Review: A Necessary But Not Sufficient Condition

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by Michael Mann and Gavin Schmidt

On this site we emphasize conclusions that are supported by “peer-reviewed” climate research. That is, research that has been published by one or more scientists in a scholarly scientific journal after review by one or more experts in the scientists’ same field (‘peers’) for accuracy and validity. What is so important about “Peer Review”? As Chris Mooney has lucidly put it:

[Peer Review] is an undisputed cornerstone of modern science. Central to the competitive clash of ideas that moves knowledge forward, peer review enjoys so much renown in the scientific community that studies lacking its imprimatur meet with automatic skepticism. Academic reputations hinge on an ability to get work through peer review and into leading journals; university presses employ peer review to decide which books they’re willing to publish; and federal agencies like the National Institutes of Health use peer review to weigh the merits of applications for federal research grants.

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Is Climate Modelling Science?

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At first glance this seems like a strange question. Isn’t science precisely the quantification of observations into a theory or model and then using that to make predictions? Yes. And are those predictions in different cases then tested against observations again and again to either validate those models or generate ideas for potential improvements? Yes, again. So the fact that climate modelling was recently singled out as being somehow non-scientific seems absurd.
par Gavin Schmidt (traduit par Gilles Delaygue)

A première vue, cela semble une question étrange. Est-ce-que la science n’est pas précisément la quantification d’observations dans une théorie ou un modèle, et ensuite son utilisation pour faire des prédictions ? Oui. Et est-ce-que ces prédictions de différents cas sont ensuite confrontées, maintes fois, aux observations, afin soit de valider ces modèles ou bien de faire émerger des idées d’amélioration ? Oui, encore une fois. Ainsi la mise à l’index récente de la modélisation climatique comme quelque chose de non scientifique semble absurde.

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Recent Warming But No Trend in Galactic Cosmic Rays

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There is little evidence for a connection between solar activity (as inferred from trends in galactic cosmic rays) and recent global warming. Since the paper by Friis-Christensen and Lassen (1991), there has been an enhanced controversy about the role of solar activity for earth’s climate. Svensmark (1998) later proposed that changes in the inter-planetary magnetic fields (IMF) resulting from variations on the sun can affect the climate through galactic cosmic rays (GCR) by modulating earth’s cloud cover. Svensmark and others have also argued that recent global warming has been a result of solar activity and reduced cloud cover. Damon and Laut have criticized their hypothesis and argue that the work by both Friis-Christensen and Lassen and Svensmark contain serious flaws. For one thing, it is clear that the GCR does not contain any clear and significant long-term trend (e.g. Fig. 1, but also in papers by Svensmark).

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Temperature Variations in Past Centuries and the so-called "Hockey Stick"

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Instrumental data describing large-scale surface temperature changes are only available for roughly the past 150 years. Estimates of surface temperature changes further back in time must therefore make use of the few long available instrumental records or historical documents and natural archives or ‘climate proxy’ indicators, such as tree rings, corals, ice cores and lake sediments, and historical documents to reconstruct patterns of past surface temperature change. Due to the paucity of data in the Southern Hemisphere, recent studies have emphasized the reconstruction of Northern Hemisphere (NH) mean, rather than global mean temperatures over roughly the past 1000 years.

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