Cosa ci dice il Mediterraneo sulle glaciazione del Plio–Pleistocene
Lo studio dell'area fornisce informazioni rilevanti su quello che è accaduto al clima negli ultimi 5 milioni di anni. Un articolo di Florence Colleoni, Simona Masina, Alessandra Negri e Alice Marzocchi sulla rivista Earth and Planetary Science Letters
Image credits: CC from kern.justin at Flickr
Lo studio approfondito dell’area Mediterranea potrebbe fornire informazioni rilevanti su quello che è accaduto al clima negli ultimi 5 milioni di anni, all’inizio delle delle glaciazioni dell’emisfero settentrionale. Questo è il tema principale di un articolo scritto dai ricercatori del CMCC Florence Colleoni, Simona Masina, Alessandra Negri e Alice Marzocchi, ora pubblicato nella rivista Earth and Planetary Science Letters con il titolo “Plio–Pleistocene high–low latitude climate interplay: A Mediterranean point of view”. I risultati della ricerca, sostengono gli autori, confermano che il bacino Mediterraneo è un luogo ideale per lo studio dell’interrelazione su ampie scale temporali tra i climi di alte e basse latitudini.
L'abstract dell'articolo (in inglese)
The high–low latitude climate interplay during the Plio–Pleistocene global cooling is not yet well understood.
Insight
on the Mediterranean region can provide some clues about past
significant climate changes since the basin reflects the climate
dynamics of both high-latitude and low-latitude regions, being connected
to the North Atlantic and subjected to monsoon influence. Here we shade
light on this connection problem by performing a spectral analysis on
an Eastern Mediterranean stack of planktonic records spanning the last 5
Ma and by further comparing it to North Atlantic and Pacific deep- and
surface-water records. Our main conclusion is that the Mediterranean
detected the main global climate transitions over the last 5 Myr
although
sapropel depositions indicate that it remained influenced by
the African summer monsoon during the whole interval. Our analysis
reveals that until 2.2 Ma the Mediterranean planktonic record is driven
by regional processes dominated by precession. The progressive emergence
of the 41-kyr frequency in the Mediterranean records around 2.8 Ma
suggests that, since this date, the Mediterranean was more and more
affected by the high-latitude climate dynamics forcing than by the
low-latitude one. Moreover, during the ongoing Plio–Pleistocene cooling,
the 41-kyr frequency signal in the Mediterranean records anticipated
high-latitude deep-water response to the intensification of the Northern
Hemisphere Glaciations (NHG)
and lagged the signal in tropical
latitudes. Finally, toward 1.2 Ma the results suggest that the
progressive shift from the 41-kyr to the 100-kyr frequency was led by
the northern high latitudes. Overall, our results confirm that the
Mediterranean is an ideal site to study the interplay between high and
low latitude climates.
La versione integrale del papaer si può leggere qui
Image credits: CC from kern.justin at Flickr
Leggi anche su Climate Science and Policy (in inglese):
- The Three Million Years Ago Dilemma: the Beginning of the Ice Ages, Florence Colleoni (CMCC) looks at paleoclimate processes and focuses hypothesis about the Pliocene period, when the continental configuration was almost similar to present-day and when, until 3 Million years ago, the climate was warmer than today.
- Discovering The Great Warming: Lessons from The Ancient Earth (video), archeologist Brian Fagan, author of The Great Warming Climate Change and The Rise and Fall of Civilizations, explains how ancient Climate Change affected the Earth in the past and how some civilizations (such are the Pueblo Indian from Chaco Canyon, New Mexico, in the 11th century, or the Egyptian civilization in 2180 BC) were able to adapt to the changed climate while other civilizations perished under the effect of a silent elephant walking across centuries.
