Why the Cooling over the Last 50
Myr?
qThe collision of
Indian and Asia happened around 40 Myr ago.
qThe collision
produced the Himalayas and a huge area of uplifted
terrain called the Tibetan Plateau.
qThe Himalayas
Mountains provided fresh, readily erodable surfaces
on which chemical weathering could proceed
rapidly.
qAt the same time,
the uplifting of the Tibetan Plateau create seasonal
monsoon rainfalls, which provided the water needed for
chemical weathering.
qTherefore, the
collision of India and Asia enhanced the chemical
weathering process and brought down the atmospheric CO2
level to the relatively low values that prevail
today.
qThis reduced the
greenhouse effect and cooled down the climate over
the last 50 Myr.
(from The Earth System)