How CO2 can change the Westerlies

Science : The westerlies are the prevailing winds in the middle latitudes of Earth’s atmosphere, blowing from west to east between the high-pressure areas of the subtropics and the low-pressure areas over the poles. They have strengthened and shifted poleward over the past 50 years, possibly in response to warming from rising concentrations of atmospheric carbon dioxide. Something similar appears to have happened 17,000 years ago at the end of the last ice age: Earth warmed, atmospheric CO ₂ increased, and the Southern Hemisphere westerlies seem to have shifted toward Antarctica. Data reported by R. F. Anderson and colleagues suggest that the shift17,000 years ago occurred before the warming and that it caused the CO ₂ increase.The CO ₂ that appeared in the atmosphere 17,000 years ago came from theoceans rather than from anthropogenic emissions. It was vented from the deep ocean up to the atmosphere in the vicinity of Antarctica. The southern westerlies are important in this context because they can alter the oceanic circulation in a way that vents CO ₂ from the ocean interior up to the atmosphere. Related Link Wind-Driven Upwelling in the Southern Ocean and the Deglacial Rise in Atmospheric CO ₂