The worst El Nino weather ever recorded, the source of catastrophic floods and droughts in 14 countries from Peru to Australia, may repeat its performance next year.
Although it is long past the time that the El Nino weather should have ended, torrential rains and scorching drought beyond all records continue in South America and on other continents.
Other meteorological signs such as sea surface temperature off South America remain unusually abnormal, more than 10 degrees above normal, a sign usually associated with severe El Nino conditions, according to officials at the National Oceanic and Atmospheric Administration.
At the same time, one indicator--air pressure--is almost back to normal in the southern Pacific, where El Nino weather patterns are centered.
"It is unbelievable to me that we could keep going with these two counter trends," said Eugene Rasmusson, chief of the diagnostic branch of the climate analysis center of NOAA. "Either we will go back to more normal patterns or we will have two years of El Nino back to back, something that is without precedent in the historical record," he said.
As for predictions of which way the weather will go, Rasmusson said, "it's all speculation, we are in a no-man's land because this is so far beyond anything we have experienced, an event so intense and so extreme that we can't predict" what will happen next.
Severe episodes of the El Nino weather patterns occur irregularly, sometimes as often as every three or four years and sometimes not recurring for a decade.
El Nino brings unusual ocean winds and currents that may drop heavy rains off the South American coast, cause droughts on the opposite side of the Pacific Ocean in Australia and Indonesia, and alter weather systems all over the globe.
El Nino, meaning "the child" was named by South American fishermen because it normally begins near Christmas, when abnormally warm and plankton-free waters ruin fishing grounds.
In several South American countries and on Pacific Islands, said Rasmusson, "we are so far over the previous records they are not even close." In some cases the records are 300 percent more than the previous all-time high rainfall.
The usual amount of rainfall in May in Ecuador, for example, is about 1.9 inches. But this year's rainfall in May was 27 inches in Guayaquil. Since last fall the city has had about 10.4 feet of rain.
The worst drought on record--statistics have been kept for 50 to 100 years--continues in Hawaii and the Philippines. Drought in southern Africa continues. And storms unlike any previously recorded in the Pacific have occurred.
In Polynesia, Rasmusson said, hurricanes are not expected more than once in about 50 years. This year there have been six.
The worst disasters this year have occurred in South America and Australia. No complete estimates of the loss of life and damage to property have been made, but NOAA has set minimal estimates of the dead at about 1,000, of those who had to flee their homes at more than 120,000, and the damage at more than $8 billion.
El Nino appears to be the single most important reason for the bizarre weather patterns around the globe. In addition to El Nino, weather researchers have noted that a four- or five-decade period of especially mild weather was broken in the 1970s, and stormy variable weather appears somewhat more common now, although such long-term patterns are largely speculation, the researchers said.
The El Chichon volcano, which spouted millions of tons of ash and chemicals into the upper atmosphere last spring, probably is not responsible for any significant change in the weather, or for any of the catastrophic weather events recorded this year, scientists said.
J. Murray Mitchell, of the climate analysis section of NOAA, said that the layer of dust now circling the globe has not had time to cool the seas by any significant amount, and the energy stored in the sea temperature is the main engine driving the earth's weather. Effects from El Chichon, if there are significant ones, should not begin until late this year or next year, Mitchell said.
As scientists explain it, El Nino is a little-understood event which drastically alters one of the main pillars of the world weather system. Three places around the globe--near Indonesia, over southern Africa, and over the Amazon basin--generate much of the world's weather.
They are called spots of "convergence" and exist over large areas where the water or land is quite warm. The warmth from the ground rises rapidly, creating great updrafts. The upward movement of air currents pulls in nearby air masses.
The convergence center in the southwestern Pacific Ocean off Indonesia is said to be one of the most powerful and the most unstable. Convergence centers over land are more predictable because land temperatures do not change as rapidly and do not hold so much pent-up heat energy as sea water does.
Also, other convergence centers stand against mountain ranges and other topographical features that help hold them in place.
Convergence is a phenomenon that increases in speed and power with the seasons, and the centers shift within limits all year long.
But the convergence center that usually sits over the Pacific off Australia and Indonesia is more unstable and its breakdown and re-formation thousands of miles toward South America is believed to be the source of the El Nino weather patterns.
When the convergence center moves toward South America it takes rain from Australia and dumps it instead on Pacific Islands and the South American coast.
Normally, the winds of the South Pacific flow reliably from the east toward the convergence center in the west. The water also tends to pile up in the western Pacific as if a fan were blowing water toward one end of a bathtub. High pressure hovers nearer South America and low pressure over the west.
When events--and scientists are not sure what might be the triggering events--move the convergence center eastward into mid-ocean, a series of other changes begin.
Winds flowing from east to west lessen, and in the most severe events such as the one that began just over a year ago, the winds reverse direction. Water is shifted from west to east as well. Ocean currents passing the South American continent off Ecuador and Peru are altered. They warm up as much as 13 degrees Fahrenheit.
In addition, a natural upwelling of cold water and chemical nutrients off the South American coast halts as normal currents are overridden by the warm waters from the west. The lack of nutrients coming up to feed plankton, which in turn are food for larger marine life, drive fish away from the region of the warm currents along the South American coast, creating havoc for the fishing industry.