The Heat Is Online

El Nino Impacted by Atmospheric Warming

"Is Global Warming Magnifying El Niño? With Record Temperatures Worldwide, Experts Study Linkage in Weather Events"

By Curt Suplee

Washington Post Staff Writer

June 9, 1998

Global warming appears to be making the impact of El Nino more severe,federal officials said yesterday, and that may help explain why the first half of 1998 has set temperature records worldwide.

The current El Nino, an abnormal flux of hot ocean water to the eastern Pacific that began in mid-1997 and is now on the wane, coincided with and potentially reinforced a planet-spanning warm spell. Not only was 1997 the "warmest year on record," but "global temperatures in the first five months of this year have been unprecedented," Vice President Gore told a White House gathering of scientists and reporters.

In addition, a new analysis, released at the meeting by the National Oceanic and Atmospheric Administration, indicates that major El Nino events have become more frequent and more severe in the past two decades. Preliminary evidence suggests the phenomenon may be linked to rising worldwide temperatures, although the exact relationship, if any, is not known.

"This wetter and warmer winter that we've just experienced gives us a glimpse of what we can expect in a greenhouse-gas globally warmed world," said NOAA Administrator D. James Baker. NOAA's latest update shows that few areas of America were unaffected by the 1997-98 El Nino, which was the strongest recorded in this century,  eclipsing even the 1982-83 event for prolonged intensity. "Across the United States, temperatures were 2 1/2 degrees higher than average. The Northeast was 4.4 degrees warmer than normal, and in the Great Lakes region the difference was a full 6.4 degrees," Gore said. Thirteen states set temperature records, including a March high of 95 in Maryland, and 88 to 90 in far northern New England.

In addition, Maryland and Virginia -- along with three other states -- experienced their wettest five months since 1895, with 141 percent and 162 percent of normal precipitation, respectively.

Gore and several NOAA commentators stressed that there is no way of knowing whether global warming -- which has amounted to about 1 degree Fahrenheit over the past cen tury -- is causing changes in the frequency or severity of El Nino episodes, which occur as a result of normal fluctuations in water and wind patterns in the Pacific Ocean every three to seven years.

"But we know that as a result of global warming, there is more heat in the climate system and it is heat that drives El Nino. So when El Nino comes," Gore said, "the effects are likely to be compounded by global warming."

Thomas R. Karl, head of NOAA's National Climatic Data Center in Asheville, N.C., noted temperatures from the first five months of this year were higher than normal by an amount "far exceeding anything we've seen in the past." Global average temperatures were about half a degree higher than the previous record for the same period.

Karl cautioned that it is impossible to generalize from data for a single year -- or even a few years. Nonetheless, Karl said, "one of the things we want to look at very closely is whether this is an early indication of an acceleration of the global warming we've seen over the past few decades. .. . When we look at the past, it's not uncommon sometimes to have jumps in the climate system," signaling a change to new averages.

In the short term, however, "this summer's forecast is calling for a return to normal," Baker said. "For the East Coast and for the most active part of the hurricane season, El Nino will not be a factor. That is, we expect a normal number of hurricanes, not the decreased number we saw last summer."

Through the end of the year, there is an increased probability of more rain for the upper Midwest and Pacific Northwest, and less for the Southeast and Southwest, Baker said. Next winter may be colder than normal overall in the United States, perhaps as a result of El Nino's opposite -- a cooling in the eastern Pacific called La Nina -- that often follows an El Nino episode.

Ants Leetmaa, director of NOAA's Climate Prediction Center here, added, "We think that normal rains, although slightly delayed, will be coming back to the south part of Mexico in about two weeks or so, which should be some help in suppressing the wildfires" there.

Gore said the United States will help Mexico to fight El Nino-induced fires, and "replant and restore damaged forests," especially those "rich in biodiversity."

He urged Hill action on the administration plan for $6.3 billion in tax and research incentives over five years to encourage energy-efficient and less polluting technologies.

Copyright 1998 The Washington Post Company