February 25, 2017
Do you know the saying, “The more things change, the more they stay the same?” It’s a translation of the French proverb, “plus ça change, plus c’est la même chose,” written in the mid-1800s by journalist, author, Le Figaro editor, and floriculturist Jean-Baptiste Alphonse Karr.
I wondered if, in this era of climate change, Karr would edit his quote.
Climate is generally defined as “average weather,” and average weather always changes, of course. The problem we face now is that we seem to have accelerated the process of natural change so much that things might never be the same. Already, plants and animals are adapting.
Trees have retreated up the Sierra Nevada slopes, plants in the Santa Rosa Mountains in Southern California have moved 213 feet upward in the past 30 years, and small animals have taken up residence at higher elevations in Yosemite. Butterflies appear earlier in the Central Valley.
Since 1895, average annual air temperatures in California have increased by about 1.5 degrees, with minimum temperatures rising almost twice as fast as maximum temperatures. Scientists predict an additional 2.7-degree average increase in temperature between 2000 and 2050.
The extra heat isn’t evenly distributed, though.
“If you look at the patterns, you see greater warming predicted for spring and summer,” says Marin master gardener Kathy Hunting, who teaches “Climate Change in the Garden” workshops (go to marinmg.ucanr.edu for upcoming dates). “That means we’ll have drier soil and less water available for plants during their growing season, more frequent, hotter and longer heat waves, and more winter storms.”
The wet gets wetter. The dry gets drier.
So, what’s a gardener to do?
Monitor your garden knowing that diseases and insects may change as the climate shifts. Work your soil to make moisture more readily available in dry times and improve drainage in wet times. Choose plants adapted to our climate and your microclimate. Reduce the number of thirsty plants, and consider planting native species. Plant in the fall or spring so plants have water to become established. Bring pollinator species into your garden especially if you’re growing edibles. Be aware of plants that create wildfire risk.
If this sounds familiar, it’s because master gardeners have shared these gardening practices with the public for years.
“The cool thing that comes from knowing about the expected impacts of climate change is that how you should be gardening now is definitely how you should be gardening for the future,” Hunting says. “You should just do more of what you already should be doing.”
And, it turns out that doing these things to mitigate the effect of climate change might actually help reduce global warming.
One simple idea is to plant trees for summer shade and winter windbreaks, thus reducing energy needs and carbon dioxide (CO2) emissions. Another is to plant a vegetable garden.
At Pepperdine University, students measured the photosynthetic rate, conductance, and internal CO2 for tomato and raspberry leaves and concluded, “According to our empirical data, the quantitative carbon absorption from a home garden creates a substantial impact on atmospheric CO2 reduction over a year.”
SMALL THINGS MATTER
At the University of Santa Barbara, research professor David Cleveland and his students demonstrated that greenhouse gas emissions could be cut by an average of 2 kilograms for every kilo of homegrown vegetables when compared to conventionally produced, store-bought vegetables. It depends on how efficiently the homegrown vegetables are produced, though, and small things matter. Take composting, for example. Home composting not done well emits methane that in large facilities might have been captured and burned to generate electricity.
Still, the researchers calculated that vegetable gardens could potentially contribute 7.8 percent of California’s 2020 target for reducing greenhouse gas emissions per year.
Thus, the more plants we grow, the more we might effect change.
As Karr wrote in his 1854 book, “A Tour Round My Garden,” “Some people are always grumbling because roses have thorns; I am thankful that thorns have roses.”