The numbers are in, says The New York Times: 2012 was the hottest year ever recorded in the contiguous U.S. 2012 also turned out to be the second-worst on record for climate extremes, amassing 11 weather disasters that exceeded $1 billion in costs, including tornadoes, freak storms, floods and catastrophic drought. Globally, the decade from 2000 to 2010 was the warmest on record. Nobody who is under 28 has lived through a month of global temperatures that fell below the 20th century average, because the last such month was February 1985. Welcome to a warmer world.
Not that everyone has noticed a warming trend. The ice caps may be shrinking and glaciers in retreat, but your particular experience of global climate change depends on where you live and where you’ve been. In Britain, where I spent last fall, gardeners certainly believe in global warming and have come to accept that they can grow many tender plants they couldn’t grow before. But the most conspicuous weather features in Britain now are alternating droughts and floods — and this in a place where once it seemed to drizzle, semi-constantly, year round.
Back in Eugene, at this year’s Good Earth Home Show, I went to a talk by Carol Deppe, a geneticist and plant breeder who is also, as plant breeders must be, an observant and systematic gardener-farmer. Deppe’s take on climate change is that it isn’t rising temperatures we’ll notice so much as those extreme weather events. Disrupted climate patterns mean we are increasingly likely “to get someone else’s weather.”
What changes could gardeners here in the Willamette Valley be making in response to climate change? Weather uncertainty should be a more powerful guide than rising global temperature, Deppe argues. She points out that our last three summers in the valley have been noticeably cool — and says that could well be our future. Rather than planting USDA Zone 9 plants, we should, if anything, be planting for a colder zone: “Be ready for more erratic weather with larger extremes,” she says. “To be useful, a fruit or nut tree needs to survive every year, not just the average year. Stick with plants right in the middle of their comfort zone — it gives you some leeway.”
Deppe suggests we begin watering only our food gardens, not our landscaping. One thing we can probably count on is a less reliable water supply. Rainfall in the valley has always been variable and can only become more so — and snowpack in the mountains is expected to decrease. We should be looking for more drought tolerance in our crops and landscapes, Deppe suggests, rather than more heat tolerance.
In the food garden, allot most space to things you like that are easiest to grow. Plant more fruit and nut trees, reliable and preferably self-fruitful varieties such as Brooks plum and filbert (blight-resistant filberts are now available). Deppe suggests using wider spacing for greater drought hardiness and less need of irrigation. Today, most people irrigate fruit and nut trees. Pioneers didn’t, but they spaced their trees more widely. Don’t plant too much of one thing because insect pests and pollinators are also affected by climate change in unpredictable ways. Plant mixed orchards, mixed hedges.
Diversity is good in the vegetable garden, too. Plant root crops — they are less sensitive to weather than grains are. Expect to replant some crops, especially early in the year. Or hedge your bets: make repeated, smaller plantings on successive dates, especially early and late in the season. Use row covers. Use more transplants, so you have more control over the early stages of growth, and include short-season varieties. An early tomato such as Stupice has a better chance of ripening in a cool summer. And during the last period of marked climate warming, autumns in the Pacific Northwest became drier, so we might have to be prepared to water a fall cover crop, instead of waiting for the rain.
Deppe is the author of a book I reviewed for EW in January 2011, The Resilient Gardener: Food Production and Self-Reliance in Uncertain Times (Chelsea Green). Deppe grows much of her own food, and has applied her breeding skills to the selection of corn, bean and squash varieties that are both tasty and uniquely appropriate for her land on the edge of Corvallis. And, quite possibly, for yours, if you live in the Willamette Valley. Deppe distributes her Northwest-bred, organic-adapted varieties through an email seed list available by request to email@example.com
Join friends and neighbors for the 2013 Green Neighbors Faire
Creating Green Community Culture
Saturday, Feb. 23, 9:30 am to 3 pm, First United Methodist Church, 1376 Olive St., Eugene
• Learn about a planned City of Eugene community climate and energy education campaign
• Presentations and panels on food, economics, neighborhoods
• Skill building: practical how-to info on food, bees, chickens, compost, conservation etc. For more information, visit www.eugenesustainability.org or phone 686-6761