Air of uncertainty: Spotlight on agriculture in a climate-change age

There is no question the San Joaquin Valley is the epicenter of farm activity in California. That being said, in living in the Valley in Fresno, over a period of roughly three-and-a-half decades, what I have watched unfold before my very eyes is the incursion of the urban form onto what was once productive ag land.

"CO mixing ratio (ppbv) @ 850 hPa"
“CO mixing ratio (ppbv) @ 850 hPa”

As a matter of fact, throughout the entire eight-county San Joaquin Valley, this is an oft-repeated story – retail centers, residential dwellings, schools, hospitals, industrial and manufacturing complexes, you name it, residing on what was once formerly fertile if not fabled farm land. If this wasn’t enough, there is another adversarial threat to crop growing – climate change and the temperature rise associated with it.

In an “FGN” (“Fruit Growers News”) article in the July 2013 issue, Assistant Editor Gary Pullano wrote, “Climate change is impacting how fruit growers are managing their orchards, according to a Penn State University horticulture specialist.”1

Among points made by the frequently cited horticulture specialist – Rob Crassweller – in the Pullano piece is this: “‘It is a change as far as the swings and erratic patterns – [growers] see it, and appreciate that it’s increasing. About 1980, indicators began to show temperatures trending above average.”

Accompanying the text in question is a graphic from Global Change Biology (2011). Reflected in that graphic is “End of growing season date: 1982 to 2008” on which two lines are plotted: “Last day of season” and “Linear trend.”

What the graph reveals is, in 1990, the last day of the growing season was Nov. 15, while the growing season’s last day in 2008 was Nov. 17. Meanwhile, the earliest last-growing-day recorded was Oct. 24 in 2000 with the second earliest last-growing-day being Oct. 26 in year 1993.

The Linear trend overall was upward meaning the end of the growing season is getting later and later.

One important question to ask is how the rise in carbon dioxide (CO2) levels in the atmosphere “from 280 parts per million in 1750 to 390 in 2010,” as pointed out in the Pullano piece, has affected crop health. FYI and for reference purposes, the introduction of the Industrial Revolution occurred circa 1760, according to the “Random House Webster’s College Dictionary” (1991 ed., p. 687).

“The possible impacts on fruit production include not only the length of the growing season, but an influx of insects and diseases,” the FGN assistant editor noted.

In terms of added atmospheric CO2 concentration, added Pullano: “For the first time, scientists recently measured an average concentration of 400 parts per million in Mauna Loa, Hawaii, where the National Oceanic and Atmospheric Administration observatory is located.”

Physical features potentially affected by climate change are:

  • Weather: with the potential for more severe weather-related events – storms, hurricanes, tornados, etc.
  • Temperature: with the potential for higher temperatures and sustained higher temperatures
  • Ecosystems: with the potential for changes in ecosystems and species habitat
  • Water: with the potential to change supplies, storage and distribution

“Erratic weather trends are likely to lead to an increase in non-tornado winds, increased storms in warmer months like July and August and a heightened likelihood of hail,” Pullano wrote.

Toxic-emissions releases from transportation, energy production, industry, construction and demolition, agriculture, residential, business (commercial activity) and naturally occurring phenomena like volcanic activity, wildfires caused by lightning strikes, etc., is, apparently, what is behind the increased CO2 in the atmosphere.

Increased pressures that have resulted from all of the above, combined are having a negative contributory effect on food (and cotton) grown, food (and clothing) necessary to sustain world life.

Agriculture, unfortunately, has suffered from the effects of air pollution and climate change.

That said, my hope is global warming’s impact on farming doesn’t get worse before it gets better; in my view it is not too late to correct a deficit situation.

Adding to this, first and foremost, I think 263 years of CO2 growth is long enough – too long, in fact. A redirect on climate change as in less climate instability and more climate predictability – what do you say?!


  1. Gary Pullano, “Adjusting orchard practices to climate change,” “FGN” (“Fruit Growers News”), July 2013, pp. 20 & 22,

Image above: NASA

– Alan Kandel

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