Why is Antarctica not showing a clear global warming signal? An assessment of recent trends in the context of the past 2000 years

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Dre Anaïs Orsi, Laboratoire des Sciences du Climat et de l’Environnement, CEA Saclay

Mercredi 10 octobre 2018 à 11h - Wednesday, October 10 at 11am

Local PK-1140, 201 ave. Président-Kennedy, UQAM

Résumé / Abstract

The Antarctic continent is one of the most remote places on Earth, and yet, it is a keyThe Antarctic continent is one of the most remote places on Earth, and yet, it is a key component of the climate system. With the recent climate change, we expect Polar Regions to warm more than the rest of the planet in the coming decades. Yet, even in the satellite era (since 1979), we are unable to say whether many parts of Antarctica have been warming or cooling. This is due in part because of the very large interannual climate variability, which masks small trends, and in part because of the very limited network of in-situ observations. Temperature proxies from ice cores are a key to improving our knowledge of climate variability in Antarctica, not only for the distant past, but also for the last 50 years.

Here, we will review the current knowledge of the Antarctic temperature climatology and trends, from in-situ observations and satellite data. To go beyond the instrumental period, we will review existing temperature proxies, and explore which ones are suitable to answer which questions. In particular, we will present a compilation of 2000-year water isotope records over all of Antarctica (as part of the Pages-2K initiative), and provide 7 regional climate reconstructions around the continent. We will discuss the features of centennial to decadal scale climate variability in the continent, and put the recent period in the context of the past 2000 years. Finally, we will present a new temperature proxy, based on the analysis of inert gas isotopes (N2 and Ar), and explore the potential for more quantitative temperature reconstructions from Antarctic ice cores in the future.

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Why is Antarctica not showing a clear global warming signal? An assessment of recent trends in the context of the past 2000 years