While there is widespread agreement that human activities are warming the climate, there has been little consensus on the effect this warming may have on the large scale atmospheric dynamics that shape the Earth’s climate. Now, a new study has found that the principal loop of winds – known as the Walker circulation – that drives climate and ocean behavior across the tropical Pacific is slowing down and causing the climate to drift towards a more El Niño-like state. The Walker circulation spans almost half the circumference of the Earth and affects weather patterns globally.
Vecchi, from the National Oceanic & Atmospheric Administration, said that the research team had identified a 3.5 percent weakening in the Walker circulation that has occurred since the mid-1800s. They also cite evidence that it may weaken another 10 percent by 2100. “There is an indication that the slowdown may be intensifying. The trend since World War II is larger than that over the entire record, and the long-term trend is larger than what is expected from natural climate variability,” Vechi added.