by P. Homewood, February 11, 2019 in NotaLotofPeopleKnowThat
London, 11 February: The scientific paper behind newspaper claims that insect populations were threatened with extinction was based on data known to be unreliable. That’s according to the Global Warming Policy Foundation, which today called for the paper to be withdrawn.
The paper, by US scientists Bradford C Lister and Andres Garcia, claimed that a rapid decline in insect populations in a rainforest in Puerto Rico was the result of rising temperatures. The Washington Post called the study “hyperalarming”, while the Guardian discussed climate change causing “insect collapse”.
However, the authors’ evidence that temperatures had, in fact, risen turns out to be based on a single weather station, which was known to be unreliable because of undocumented changes to equipment and location resulting in a substantial and abrupt increase in recorded temperatures in September 1992.
Since 1992, temperatures at this station have actually declined.
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by P. Homewood, January 20, 2019 in NotaLotofPeople KnowThat
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Clearly the whole study is worthless, and the paper should be withdrawn.
There are some alarming facts about all of this:
1) Why did the researchers not suspect that the temperature data looked hopelessly wrong at the outset?
2) Why did peer review not do the basic checks that I did?
3) The study carries out some mindbendingly complex statistical analysis, linking arthropod decline to rising temperatures. But how can this analysis have been robust, when the temperature data was hopelessly wrong?
The conclusion is that the faulty temperature data matched the researchers’ expectations of climate warming, and consequently they never bothered to crosscheck. It would after all have been extremely simple to have asked the people who maintain the data.
Whether or not arthropods are in decline I have no idea. But by blaming non existent climate warming, there is a very real danger that the true cause is being missed. Indeed, looking at those graphs, it may well be climate cooling that is responsible.
I plan to contact PNAS, who published the paper, to request that it be withdrawn.
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by University of Barcelona, November 9, 2018 in ScienceDaily
Regional differences regarding other reconstructions
The results of the study show a temperature rise in the beginning of the Holocene, reaching the highest values in the Holocene Climate Optimum (about 7,800 years ago). There are also high temperatures until about 6,000 years ago, when a decline of temperature started and led to the lowest values in the first stage of the late Holocene (about 4,200 and 2,000 years ago).
Last, researchers detected a rise of temperatures over the two last millenniums, but they state they have to be careful with these data. “We cannot guarantee the observed rise in the reconstruction results from a temperature rise only, we cannot rule out other variables that can influence at other levels, such as the gradual increase of the anthropic activity in the area, which can change the community of Chironomidae to species that adapt to higher temperatures, but there are also human influence indicators,” says Narcís Prat.
Although these conclusions can coincide with other paleoclimate reconstructions, results also highlight some divergences at a regional level. “These differences can occur due the fact that some indicators point out to different seasonal signs. Therefore, Chironomidae are indicators of temperature in summer, while others such as chrysophites or alkenones are related to winter/spring temperatures,” notes the researcher.
A tool to evaluate climate trends
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La géologie, une science plus que passionnante … et diverse
