Poleward and weakened westerlies during Pliocene warmth

Area of Science:

• Paleoclimatology
• Atmospheric Science
• Oceanography

Background:

• Mid-latitude westerly winds (westerlies) are crucial for ocean circulation and climate regulation.
• Evidence suggests westerly wind belts are shifting poleward due to human activities.
• Understanding past westerlies during warm periods like the Pliocene aids future climate predictions.

Purpose of the Study:

• Reconstruct Pliocene westerlies position and strength.
• Investigate drivers of westerlies shifts during past warm periods.
• Inform predictions of future wind pattern changes under global warming.

Main Methods:

• Dust and export productivity reconstructions from the Pliocene and early Pleistocene.
• Analysis of North Pacific dust fluxes.
• Comparison with climate modeling results and other global dust records.

Main Results:

• Pliocene westerlies were weaker and more poleward than post-iNHG glacial periods.
• Increased North Pacific dust fluxes coincided with Northern Hemisphere glaciation.
• Dust and productivity changes tracked Plio-Pleistocene glacial-interglacial cycles.

Conclusions:

• Westerlies shifts were primarily driven by Plio-Pleistocene thermal gradients and ice volume.
• Changes in westerlies were globally synchronous.
• Future warming may lead to continued poleward movement and weakening of westerlies.