Axel Bojanowski auf Welt.de:
Forscheraufstand gegen Klimamodelle
Computersimulationen haben wichtige Erkenntnisse über die globale Erwärmung geliefert. Zahlreiche Wissenschaftler aber sehen eine Grenze erreicht – und sie kritisieren das Schweigen der Kollegen.
Ihre Unzufriedenheit mit Computermodellen trugen Klimaforscher selten nach außen. Eine Ausnahme machte der Russe Ilya Polyak. Kurz vor Abgabe ihrer gemeinsamen Studie 1997 habe Polyak den finalen Absatz eigenmächtig geändert, erzählt sein Co-Autor Gerald North. Nun stand dort, dass Klimamodelle so schlecht wären, dass ihnen nicht vertraut werden könnte.
North schrieb eine Gegendarstellung zu seiner eigenen Studie. Ilya Polyak verließ die Klimaforschung, wie nicht wenige andere Wissenschaftler, die an der Arbeit mit Klimamodellen verzweifelt waren. Doch selbst Modellskeptiker fanden, dass Polyak übertrieben hatte.
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Götz Wiedenroth hat eine tolle Illustration zum Teufelskreis „Klimaschuld Propaganda, Kraftwerke sprengen, Flatterstrom“ etc. gemacht. Unbedingt mal anschauen, hier.
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In vorindustrielle Zeit war das Klima langweilig, weil das CO2 konstant war? Pustekuchen. Die Mittelalterliche Klimaanomalie und die Kleine Eiszeit haben sogar in Südamerika gewirkt. Tonello et al. 2026 im Journal of South American Earth Sciences:
Hydroclimatic variability during the last 2000 years in the southeast of Pampa plain (South America)
Highlights
- 2000 years of hydroclimatic reconstruction from SE Pampa plain lakes using pollen.
- MCA is characterized by predominantly drier than present conditions.
- MCA–LIA transition also exhibits drier than present conditions.
- LIA presents a change to more humid conditions, not fully synchronous regionally.
The Medieval Climatic Anomaly (MCA) and the Little Ice Age (LIA) have been described as global temperature anomalies, though there is a scientific concern to estimate hydrological anomalies at these times and to know the nature of the transition between these events. In this contribution we present a hydroclimatic reconstruction for the last 2000 years using a pollen index derived from the relative abundance of Cyperaceae and Chenopodiaceae, from four shallow lakes located in the southeast of the Pampa plain. The hydroecological balance index suggests drier conditions than present between 50 BCE and 1500 CE, coeval with MCA. These conditions continue during MCA-LIA transition. A positive hydrological balance during LIA suggests similar or perhaps slightly more humid conditions than the present. This change is not completely synchronous with the proposed chronology for LIA, and hydroclimatic conditions appear to have varied considerably even among sites within the same climatic zone. During the last 100 years, the complexity of signals has not allowed disentangling climatic from anthropogenic factors affecting these aquatic ecosystems. The regional paleoclimatic synthesis allows proposing MCA as a homogeneous climatic event with generalized dry conditions, whereas LIA was more heterogeneous, with humid and dry conditions at different sites in the Pampa plain. The differences should not be interpreted as climatic discrepancies but rather as different expressions that may or may not be responding to the same climatic forcing.