|The record of La Nina's and weak El Ninos that |
have occurred since the
last powerful El Nino in 1997-1998. From the
Nikkei Asian Review cited in the text.
What has caused this speculation? Normally the trade winds blow from east to west, but in January and February there were two strong westerly bursts, followed by two "slightly less powerful" ones in March and April. If such bursts continue and develop into a reversal of the trade winds, an El Nino will occur. Warm surface waters of the Pacific will be pushed easterly toward the west coast of South America.
Although highly speculative at present, a switch back to El Nino conditions may have significance in the bigger picture. La Nina conditions have permitted storage of heat in the deep waters of the Pacific. Storage of heat in the ocean takes it away from the atmosphere, keeping global warming in check. The haitus in global warming in recent years may be due to this string of La Nina events. A switch back to El Nino conditions, particularly if they last a decade or more as is common, could result in a resumption of global warming conditions. Here's a link to a Slate article on the possibility, and here's Cliff Mass's comments about it, as well as the quality of forecasts made in April, the time of these two articles.
|Typical El Nino weather conditions. From here.|
The Asian Review article also notes that because of budget cutbacks, 24 of NOAA's 55 ocean buoys in the tropical Pacific are unable to operate and send data needed for monitoring the situation.