Sunday, July 9, 2000
Abilene’s weather history
has its ups and downs
By Jerry Daniel Reed
Reporter-News Staff Writer
If global warming is a reality, it couldn’t
be proved by Abilene.
At least, not yet.
The problem with living during a climate
change is that no one knows for sure that that’s what is
happening for a long time. Climate is by definition habitual weather
over the long haul, while weather is what’s happening outdoors
right now.
Not that the past two years around Abilene
haven’t been uncommonly warm and dry, 1998 especially.
That year was the city’s fifth-hottest
ever, with an average daily year-round temperature of 66.7 degrees.
Its 13.88 inches of rainfall tied it for the fourth-driest ever.
Last year was only slightly more moderate,
with a 66.3-degree average temperature — the 10th-hottest
ever — and 16.67 inches of rain, the 18th-scantiest ever.
Until a spell of rainy weather in late May
and June, however, 2000 threatened to outdo either in extremes.
Even after a relatively cool June, the year’s
average daily temperature was on track to shatter the previous
year-round record average of 67.6 degrees, set in 1933, by 1.5
degrees.
Starting the month, the excessive daily
average heat had the city headed toward a full-year average of
69.9 degrees.
Rainfall was 44 percent below normal through
May 31. But with 5.84 inches measured during the month, Abilene
started the final half of the new century’s first year only
1.11 inches below average, at 10.21 inches.
Extraordinary heat and drought for so brief
a span in such a tiny corner of Earth’s vastness makes generalizing
climate patterns a risky proposition. That’s particularly
true because it’s been hotter and drier here for longer periods
before, most notably in the ‘50s.
Even such red-hot believers in manmade global
warming as Noam Mohr concede that tying the effects of global
warming to a particular region’s climate changes is difficult.
A physicist who heads the U.S. Public Interest Research Group,
Mohr compiled PIRG’s recent report, Storm Warning: Global
Warming and the Rising Cost of Extreme Weather.
PIRG pushes a “clean energy agenda.”
It supports sharply increasing renewable energy such as solar
power, tightening pollutant emission standards for industry and
motor vehicles, raising fuel efficiency standards for vehicles,
and ending support for energy sources it considers overly polluting
such as coal, petroleum and nuclear power.
“It’s one thing to talk of global
averages and trends, but harder to refer to regional effects,’’
Mohr explained.
Though Earth as a whole warmed by about
1 degree last century, Abilene’s climate has been remarkably
stable over the long haul.
Abilene’s average annual temperature
for the National Weather Service’s 1961-90 benchmark period
was 64.3 degrees, 0.2 of a degree lower than the average annual
temperature of 64.5 for the city’s entire 114 years of weather
records.
The weather service compares current climatological
data to that benchmark period — 1961-90 now, and soon to
be 1971-2000 — on the theory that because climate changes
gradually over time, recent long-term figures are more comparable
to today’s weather than figures from all years on record.
As for rainfall, the city’s 1961-90
average of 24.4 inches was 0.2 inches more than its 114-year average
of 24.20 inches.
Even for the nine-year span since 1990,
the city’s temperature average of 64.5 exactly hits the 114-year
average, while its 24.23-inch rainfall average for the same period
hits the historical average almost dead on target.
But no one who lived through the extended
drought of the ’50s — or the slightly less dry but hotter
spell of the ’30s — could have been faulted for embracing
the global warming theory — had it been available then.
For combining drought and heat, Abilene
has experienced nothing to match 1951-56.
Average annual rainfall then was down 19
percent at 16.16 inches, and the average temperature of 66.1 degrees
topped the historical average by 1.6 degrees.
The years 1951-60 were the city’s driest
complete decade, with 21.34 inches of rainfall annually, while
1931-40 was the hottest decade with a 65.7 degree norm.
The driest 10-year span in Abilene’s
history was 1947-56 with an average of 18.56 inches a year.
By coincidence, the city’s wettest
10-year stretch followed the driest without pause: 26.84 inches
a year from 1957-66.
During 1943-56, only three years saw above-average
rainfall in Abilene, resulting in a 14-year average of 19.13 inches.
This longest dry run in Abilene’s history was followed by
an 18-year string of mostly wet years. From 1957-74, Abilene caught
an average of 26.71 inches a year, a record average amount for
such a length of time.
This locality may be far too small to provide
appreciable evidence for or against artificial global warming.
But that’s not to say global warming might not become only
too evident even in the local climate.
The International Panel on Climate Change
predicts the temperature for the whole earth in the 21st century
could rise 6 degrees if mankind fails to sharply reduce spewing
carbon dioxide and other greenhouse gases into the air.
If Abilene were to warm up by even 4 degrees,
its annual rainfall would likely plummet. This assumes that heat
and drought move in tandem as they have in the past. Even if rainfall
were to stay the same as it gets hotter, the climate would become
drier because evaporation speeds up with heat, reminds state climatologist
John Nielsen-Gammon.
Abilene’s 10 warmest years, ranging
in average temperatures from 66.3 to 67.6 degrees, also averaged
28 percent low on rainfall, a scanty 17.60 inches a year.
Living with 28 percent less rainfall forever
could prove a mighty tall order for this city of more than 100,000
people.
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Abilene Reporter-News / Texnews / E.W. Scripps Publications
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