Wednesday, 21 September 2011

Medieval Warm Period coming to an Island near you.

New Caledonia in the Coral Sea off
Australia's Queensland coast (Google Maps)
New Caledonia or more correctly in the island's native French -Nouvelle-Calédonie - is a Melanesian island in the Coral Sea approximately 1200 Kilometres east of Australia.

That "great" reference Wikipedia tells us it was once part of Australia, although 65 million years ago.
New Caledonia is one of the northernmost parts of a (93%) submerged continent called Zealandia. It sank after rifting away from Australia 60–85 million years ago (mya) and from Antarctica between 130 and 85 mya. New Caledonia itself separated from Australia 65 mya, and has subsequently drifted in a north-easterly direction, reaching its present position about 50 mya
A new peer reviewed paper published in Quaternary Research 76: 229-242 examines Mid- to late Holocene environmental and climatic changes in New Caledonia and say that it must relate to the Northern Hemisphere Medieval Warm Period.  
(Reported on CO2 Science - H/t Climate Depot)

Fournier Swamp, New Caledonia

Wirrmann, D., Semah, A.-M., Debenay, J.-P. and Chacornac-Rault, M. 2011. Mid- to late Holocene environmental and climatic changes in New Caledonia, southwest tropical Pacific, inferred from the littoral plain Gouaro-Deva. Quaternary Research 76: 229-242. Description
Based on their multi-proxy approach to climate evaluation, the authors determined that between ca. 2640 and 2000 cal yr BP, conditions were "drier and cooler," while subsequent observations linked wetter with warmer. More specifically, they report that "between ca. 1250-500 cal yr BP the higher % of Rhizophoraceae and their peak around ca. 1080-750 cal yr BP underscore a mangrove belt development along the coastline." And they state that this episode must be related to a wetter period and "may be related to a more global phenomenon such as the MWP in the Northern Hemisphere." Thus, we consider the period AD 920-1250 to represent the MWP in this part of the southwest tropical Pacific.