The Trade Winds serve many purposes beyond the one that got them their name. They bring rains to the west and churn up the oceans, turning surface waters into rich feeding grounds, and drive weather conditions around the world. A study of air pressure records dating back to 1860 has shown the changes over time of the Walker circulation. It had weakened by 3.5% and was expected to fall by 10% by the year 2100.
“Nearly all of this is down to increases in greenhouse gas emissions,” said Dr Vecchi.
“We know this air current has an influence on weather in many regions, so we can expect there to be changes locally. Ecosystems are complex, but our concern would be that this could also affect biological productivity over a large part of the Pacific,” he added.