Widespread Forests Contributed Significantly to Climate Warming During the Middle Miocene Climate Optimum

During the Middle Miocene Climate Optimum (MMCO), widespread forests previously contributed significantly to global warming while the open Panama and Tethys Seaways functioned as "shortcuts" for the Atlantic Meridional Overturning Circulation (AMOC).

During MMCO, scientists from the Chinese Academy of Sciences' Institute of Atmospheric Physics and Institute of Tibetan Plateau Studies have shared their insights into the intricate connection between trees, ocean circulation, and climate.

They have painstakingly assembled this fascinating jigsaw, revealing the underlying relationships between these elements.

On March 15, the research was published in Palaeogeography, Palaeoclimatology, and Palaeoecology.

Lessons from Miocene for today's world

(Photo : LARS HAGBERG/AFP via Getty Images)

With the exception of Antarctica, the MMCO, roughly 16.9 to 14.7 million years ago, was a time when most of the earth's surface was covered in dense forests, as per Phys.org.

The Flexible Global Ocean-Atmosphere-Land System Model Grid-Point Version 3 was used to simulate ocean circulation in order to study the climatic dynamics during the MMCO (FGOALS-g3)

The CO2 level employed in the MMCO simulation was identical to today's, despite some proxy data suggesting that CO2 concentrations during the MMCO were as high as those predicted for the end of the 21st century.

The findings showed that the average global temperature in the MMCO was over 3°C higher than it is today, with forests having a larger impact on climate regulation than previously imagined.

The Sahara and high northern latitudes, which are presently covered with deserts and low-growing flora but were wooded during the MMCO, had exceptionally high land temperatures.

The MMCO, unlike today's land-sea distribution, had open Panama and Tethys Seaways in addition to considerable forest cover.

The simulation showed that in the western North Atlantic, fresh throughflow from the Panama Waterway mixed with high-salinity throughflow from the Tethys Seaway.

This result implied that the Tethys Seaway made up for the AMOC's contribution made by the Panama Waterway.

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Life on Miocene Epoch

Expanding open vegetation systems, such as deserts, tundra, and grasslands at the price of declining closed vegetation is the general pattern of biological change for the Miocene, such as forests, as per The University of California.

As a result, animals underwent numerous morphological modifications and temperate habitats underwent diversification.

Whether as swift-moving herbivores, huge predatory mammals and birds, or small swift birds and rodents, mammals and birds in particular evolved new shapes.

Miocene plant studies have mostly concentrated on spores and pollen.

These analyses demonstrate that 95% of the families of contemporary seed plants existed by the end of the Miocene and that no such families have disappeared since the middle of the Miocene.

The retreat of tropical ecosystems, the spread of northern coniferous forests, and the rise in seasonality are thought to be the results of a warming phase in the middle of the Miocene, followed by a cooling phase.

As a result of this transition, modern graminoids, particularly grasses, and sedges, have become more diverse.

Together with developments on land, significant new ecosystems in the sea gave rise to new forms.

Sea otters and other creatures specific to those habitats first appeared along with kelp forests.

Oceanic mammals like the Desmostylia became extinct during the same period.

Because of small shifts in the positions of the continents and generally warmer climates, the Miocene experienced a change in global circulation patterns.

These positional shifts caused some alterations in climate on each continent, but it was an overall rise in aridity brought on by the formation of mountains that encouraged the spread of grasslands.

It is simplest to describe the plate movements and associated changes in the paleoclimate by describing individual continents because the positions of continents in the Miocene era were comparable to where they currently lay.

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