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LAS CRUCES - Christmas tree grower and third-generation farmer Phil Archer, 62, recalled his days growing up when La Mesa received three or four snowfalls each winter, a few of which totaled up to 9 inches in depth, and weather in general was colder.
But these days, he said, snowfall on the farm is a rarity, and the growing season - the period between spring and fall frosts - is getting longer.
"I've noticed quite a bit of difference in the last 30 years since we've been growing pine trees," he said. "We've not been getting the cold weather we've been getting in the past. I just know it's getting warmer."
For instance, Archer said when he first launched his tree farm in 1978, the first hard fall freeze, on average, occurred around mid-October. But that has crept up to the first week of November.
Archer's temperature observations match a trend found in data from the longest continuously running climate observation station in the county.
Getting warmer
Temperature and precipitation data has been recorded from the gauges, located at New Mexico State University, since 1892. Each
After examining the station's history, state climatologist David DuBois found a trend: The average temperatures indeed have crept upward. He said that's mostly attributable to higher minimum temperatures, which have increased at a rate of about 0.38 degrees Fahrenheit per decade since 1901. But maximum temperatures, too, have seen an increase of about 0.20 degrees every 10 years, he said.
Meanwhile, overall average temperature from the station from 2001 to 2010 was about 2.3 degrees higher than in 1901 to 1910, according to DuBois.
"That really grabs you because you see a definite trend up, pretty much regardless of where you pick your reference," he said. "It's not getting as cold in the morning, so the average temperature is getting higher."
DuBois said that's similar to a trend noticed from other weather stations across the state, as well as in the western U.S.
While data shows that average weather is becoming warmer, DuBois said there's not a noticeable trend regarding the amount of precipitation that's falling locally.
Higher minimum temperatures are reflected in the U.S. Department of Agriculture hardiness zones, said John White, a former Do-a Ana County horticulture extension agent who now works for the University of Texas at El Paso. The Las Cruces area is now an 8A zone, though it used to be in the 7 range, indicating cooler winter weather.
White, who grew up in Do-a Ana County and still lives here, said that he's noticed over time more residents are planting species that, years ago, didn't stand a chance of surviving the winter. But now vegetation such as the heat-loving Saguaro cactus from Arizona is cropping up in area yards, though White said he wouldn't recommend people seek it out just yet for landscaping.
"We're seeing more cold-susceptible plants that are being grown here," he said. "I can remember when Las Cruces used to have pretty cold winters. We don't have those anymore."
But White said something else he's noticed is more-variable weather - such as periods of cold punctuated by unusual warming spells - which is problematic for plants.
Growing changes
Changing climate, of course, has implications for Do-a Ana County farmers and gardeners. Experts said certain crops may benefit, while there are negative impacts for others.
Some fruit trees, for instance, require a certain number of "chill hours," in which the temperature drops very low, as part of their life cycles, said Jeff Anderson, Do-a Ana County horticulture extension agent.
"If the hours change, you may have to adjust your varieties," he said. "And some things might not be able to grow at all."
Anderson noted, too, that cold weather can help kill off insect pests in the winter.
It's widely known that farmers of pecans, a major Do-a Ana County crop, rely on a well-timed autumn freeze that helps launch the annual harvest. And a delayed freeze can postpone harvesting activity, putting kinks in growers' marketing plans.
White pointed out that plants must use more water as the weather warms.
Mountain snowfall
Perhaps even a bigger concern than the effect on local growing conditions is changing climate a few hundred miles to the north. The snow that falls each winter in southern Colorado and northern New Mexico melts into the Rio Grande each spring, eventually feeding Elephant Butte Lake and Caballo Reservoir. From there, it both supplies Do-a Ana County and El Paso irrigators, experts said, and replenishes the aquifer in the Mesilla Valley. That groundwater is relied upon for drinking and other domestic use.
The snow season in those areas has been starting later in the year and ending earlier in the spring, said Ed Polasko, National Weather Service hydrologist in Albuquerque. Plus, springs have been drier and windier, on average, which promotes sublimation. Essentially that means the snow disappears into the atmosphere instead of melting into the river system.
"So, we may have started out with a really good snowpack, but it didn't show up in the rivers, lakes and streams," he said.
In recent years, Polasko said, snowpack has looked favorable going into the spring, but the run-off hasn't materialized. He said the 2004-05 season was "the last time we really had a normal to above-normal run-off that actually made it into Elephant Butte."
"Since then, it just hasn't happened," he said.
That's a concern to the Elephant Butte Irrigation District, which delivers water to farmers in southern Sierra County and Do-a Ana County, said Phil King, consultant hydrologist for the district. Run-off is the district's main source of water.
For instance, King said, the district had estimated last year how much water would be generated from the snowpack, only to be disappointed.
"We're missing over 100,000 acre-feet we expected to come down that didn't materialize," he said.
An acre-foot contains about 326,000 gallons, enough to supply about one to two U.S. households annually.
Questions remain
DuBois said an increase in development - more paved streets and new buildings - in the vicinity of the NMSU climate station may have influenced weather readings over the years. He said he just started in the position last year and plans to try assess the effects of development on the gauge.
Even so, DuBois said the increase still seems aligned with a trend in the West.
Is that at all tied to an increase in average temperatures around the globe?
"Surprisingly, there hasn't been a lot of work in that," he said. "I'd like to see someone actually looking at the morning lows going up, but personally I haven't seen that in a peer-reviewed journal, yet."
As far as whether the warming trend will continue in Do-a Ana County, DuBois said that's not predictable.
"It may go down," he said. "That's anybody's guess."
Archer said on his farm, trees require a hard freeze to "harden up," making them less susceptible to damage after they're excavated. So the timing of the freeze affects his time window for shipping Christmas trees in advance of the holiday. Even so, he said, he's doubtful the operation will experience a major financial impact because of warming, at least in his lifetime.
"It could be the next generation that has problems," he said. "Heck, we might be growing citrus down here. Who knows?"
Diana M. Alba can be reached at (575) 541-5443.
New Mexico State University climate station
Average min. Average max. Average*
temperature temperature temperature
•1901-1910 44.4 77.5 61.2
•1911-1920 44.0 75.4 60.0
•1921-1930 44.2 75.4 60.1
•1931-1940 43.9 75.6 60.0
•1941-1950 43.0 76.3 59.9
•1951-1960 44.0 77.4 61.0
•1961-1970 44.9 77.4 61.4
•1971-1980 44.5 76.8 60.9
•1981-1990 46.5 76.6 61.8
•1991-2000 47.7 78.0 63.1
•2001-2010 48.4 78.1 63.5
* Temperature in degrees Fahrenheit
Source: New Mexico state climatologist
On the Web
•For more information on the New Mexico Climate Center, visit: http://weather.nmsu.edu
•For more information about U.S. Department of Agriculture hardiness zones, visit the National Gardening Association: www.garden.org/zipzone
