2002 was marked by widespread U.S. drought and the return of El Niño


WASHINGTON – The climate of 2002 in the United States was characterized by warmer-than-normal temperatures and below average precipitation that led to persistent or worsening drought throughout much of the nation, according to the National Oceanic and Atmospheric Administration, or NOAA.

Working from the world’s largest statistical weather database, NOAA scientists at the National Climatic Data Center also found that 2002 is very likely to be the second warmest year on record for the globe.

The return of El Niño affected hurricanes in the Atlantic and precipitation patterns in some parts of the world.

U.S. temperatures. The average temperature for the contiguous United States in 2002 is expected to be near 53.6 degrees F, one of the 20 warmest years since national records began in 1895, but significantly cooler than last year, which was the seventh warmest year.

The average temperature during the 1895-present record is 52.8 degrees F, with the warmest year on record occurring in 1998.

Last winter was warm. The year 2002 began with another anomalously warm winter, the fourth much warmer-than-average winter in the last five years, and the summer season was one of the warmest since the 1930s.

Overall the contiguous United States temperature has risen at a rate of 1.0 degree F/Century since 1895. Much of that increase has occurred in two periods, 1910-1940, and again from the 1970s to the present.

U.S. precipitation. As the year began, moderate to extreme drought covered one-third of the contiguous United States, including much of the eastern seaboard and northwestern United States.

The combination of generally warmer- and drier-than-average conditions led to the total drought area growing to slightly more than 50 percent during the summer months, largely due to a rapid intensification of drought in the Southwest.

This value fell to 36 percent by the end of November as precipitation from landfalling tropical systems and a more active storm track helped alleviate drought in much of the eastern part of the country.

Not the ‘big one.’ The most extensive national drought coverage during the past 100 years (the period of instrumental record) occurred in July 1934 when 80 percent of the contiguous United States was in moderate to extreme drought.

Although the current drought and others of the 20th century have been widespread and of lengthy duration, tree ring records indicate that the severity of these droughts was likely surpassed by other droughts, including that of the 1570s and 1580s over much of the Southwest and northern Mexico.

Ag hurting out West. In the western United States where precipitation for 2002 is on pace to set record or near-record lows in many states, the lack of adequate rain and snow and the resulting low snowpack stressed water supplies and caused devastating impacts on agriculture.

Severe drought in Montana that began in some places more than four years ago forced farmers to abandon more than 20 percent of the winter wheat crop for the second consecutive year, the first such occurrence since the Dust Bowl era of the 1930s.

The extremely dry conditions also contributed to an extremely active wildfire season that included the largest wildfires of the past century for the states of Colorado, Arizona and Oregon.

Extremely dry conditions in the Northeast improved with four consecutive months of above-normal precipitation for the region from March through June, and abnormally dry conditions were largely absent near the end of the year.

Above-average rainfall from September through November also brought significant drought relief to the Southeast, where more than four years of drought had affected much of the region from Georgia to Virginia.

Global events. Other climate signatures typical of El Niño also emerged in countries such as Australia, India and Indonesia as the El Niño episode evolved during the year.

Drought in Australia became more widespread and severe, and a new record warm winter maximum temperature for Australia occurred.

Other conditions common during an El Niño episode included a drier-than-average summer monsoon season in India and drier than normal conditions in Indonesia during May-October.

The June-September monsoon season for India as a whole was characterized by large-scale drought with seasonal rainfall (June-September) 19 percent below normal.

In contrast, heavy rainfall in northeastern India, Nepal and Bangladesh brought severe flooding and caused approximately one thousand deaths in June.

Floods in Europe. In parts of central Europe, heavy rains fell during the first 13 days of August, causing disastrous floods on the Elbe and Danube rivers with more than 100 lives lost and damages estimated at $30 billion.

In Africa, severe drought continued across parts of the Greater Horn of Africa, and widespread flooding occurred in Morocco during November and in parts of Madagascar during January-May as four tropical cyclones impacted the island nation.

Related Story:

Earth’s 10 warmest years have all occurred since 1987

WASHINGTON – NOAA data collected from weather and climate stations, satellites, ships, buoys and floats indicate that the 2002 average global temperature will very likely be the second-warmest on record, slightly cooler than the record warm year of 1998.

The 10 warmest years have all occurred since 1987, with nine of them since 1990.

Warming trend? During the past century, global surface temperatures have increased at a rate near 1.0 degree F/Century, but the trend has been three times larger since 1976, with some of the largest temperature increases occurring in the high latitudes.

In 2002, warmer temperatures and shifts in atmospheric circulation patterns contributed to the greatest surface melt on the Greenland Ice Sheet in the 24-year satellite record.

There was also a record low level of Arctic sea ice extent in September, the lowest since satellite monitoring began in 1978, according to the National Snow and Ice Data Center.

Troposphere temps. Data collected by NOAA polar orbiting satellites and analyzed for NOAA by the University of Alabama in Huntsville and Remote Sensing Systems in Santa Rosa, Calif., indicate that temperatures centered in the middle troposphere at altitudes from two to six miles are also on pace to make 2002 the second-warmest year for the globe.

The average lower troposphere temperature (surface to about five miles) for 2002 will also very likely be the second warmest on record.

Disagreement. Analysis of the satellite record that began in 1979 shows that the global average temperature in the middle troposphere has increased, but the differing analysis techniques of the two teams result in different trends.

The Alabama team found an increase of 0.06 degrees F/decade, while a trend of 0.21° F/decade (0.115° C/decade) was found by the California team.

This compares to surface temperature increases approaching 0.3 degrees F/decade during the same period.


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