Global warming said to slow trade winds
Climate scientists have detected a change in the Pacific trade winds - also known as the Walker Circulation. It's a vast loop of air above the equatorial Pacific Ocean. Human-induced climate change appears to be the culprit. Click to expand
JB: This is Earth & Sky. Climate scientists say they?ve recorded a change in Earth?s trade winds.
DB: They think the change can be attributed, for the first time ever, to global warming.
Gabriel Vecchi: This is one of the first studies that brings together the models, the theory, and the observations in such a consistent manner to really make a very strong case that human beings are altering the trade winds system through the input of greenhouse gases.
JB: That?s Gabriel Vecchi, based at the Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey. He spoke to Earthsky about the system of Pacific trade winds known as the ?Walker Circulation.? Vecchi said that, over the past 150 years, the average speed of these winds has been observed to slow down by about 3.5 percent.
DB: The climate models he uses have ruled out natural reasons for this change – for example, volcanos or changes related to our sun. On the other hand, when data on human-caused greenhouse gas emissions are fed into the model, the results match what is observed.
Gabriel Vecchi: That said, the projections for the future are for a further weakening of around 10 percent, which is more substantial than the observed 3.5 percent weakening. And we don’t know the details of what the impact of that might be. We’re working on trying to understand it.
JB: Our thanks today to NASA: explore, discover, understand. We’re Block and Byrd for Earth & Sky.
Global Warming Cited in Wind Shift, from the Associated Press.
Trade winds’ slowdown backs warming theory, from the San Francisco Chronicle.
Slowdown in Tropical Pacific Flow Pinned on Climate Change, from NCAR and UCAR
The diagram below and the one at top show two different views of the Walker Circulation, a vast loop of air above the equatorial Pacific Ocean. (Illustration by Gabriel Vecchi, UCAR)
Our thanks to:
Gabriel Vecchi
UCAR visiting scientist
Geophysical Fluid Dynamics Laboratory
NOAA
Princeton, New Jersey
Additional Teacher Resources
NASA: Climate Change Resource Reel
From polar ice to phytoplankton, parts of the earth system are constantly changing. At NASA, scientists strive to better understand these changes and how they are interconnected. Using remote-sensing data from satellites, this research diagnoses our planets current health and will help future generations and explorers understand the earth system as a whole.
San Francisco Chronicle: Trade Winds Slowdown Backs Warming Theory
Climate scientists have documented a pronounced slowdown in the Pacific Ocean atmospheric system that drives the trade winds, a prediction of global warming theory that appears to be coming true.
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