Nancy Fresco, University of Alaska Fairbanks
Alaskan gardeners know it’s hard to grow big, juicy tomatoes here. But as the climate warms rapidly in the Far North, that could change.
Anchorage reached 90 degrees Fahrenheit (32 degrees Celsius) for the first time on record in 2019. Arctic sea ice is retreating rapidly and average annual temperatures are 3 to 4 F higher across the state (1.7 to 2 .2 C) compared to those in the middle. 20th century.
These climatic changes bring immense challenges, such as structural collapses such as the thawing of long-frozen ground and risks to life and property from increased wildfires. Agriculture is one area where climate change can indeed bring some benefits to our state, but not without obstacles and uncertainties.
As a climate researcher at the International Center for Arctic Research at the University of Alaska Fairbanks, I recently worked with other academics, farmers, and gardeners to begin studying our state’s agricultural future. . We used scaled-down global climate change models combined with information from farmers growing vegetables for local markets and tribal groups interested in gardening and food security. Our goal was to take a preliminary look at what climate change could mean for agriculture in communities across the state, from Nome to Juneau and Utqiagvik to Unalaska.
Our research suggests that planning for decades to come and even generations to come can be crucial to keeping Alaska nourished, healthy, and economically stable. We’ve created online tools to help Alaskans start thinking about the possibilities.
Cultivate in cold climates
Alaska’s vast expanse is reflected in its wide range of climatic zones, from the temperate and rainy Tongass National Forest to the arctic tundra that greens quickly but remains frigid. In Anchorage, moderated by the ocean, the first fall frost usually doesn’t arrive until late September, but historically average July temperatures were a modest 59 F (15 C). Even that is warm compared to 56 F (13 C) for Juneau and 51 F (11 C) for Nome. Here in Fairbanks, July is a little more summery, but frost often hits in August and winter temperatures regularly drop to -40 F (-40 C).
With cool summers, short growing seasons, and freezing winters, most agricultural activities in Alaska have long been limited by the state’s cold climate. Although home gardens are popular, with growers favoring hardy crops such as cabbages, potatoes and carrots, farming is a small industry. Recent data from the US Department of Agriculture counts only 541 acres of potatoes, 1,018 acres of vegetables and 22 acres of orchards in our 393 million acre state.
The crops of the future
Our climate modeling suggests a dramatically changing future for Alaskan crops by 2100, with frost-free seasons spanning not just days, but weeks or months; cumulative summer heat doubling or more; and the coldest winter days become 10 or 15 degrees less extreme.
Perhaps the most surprising projected change is in so-called “growing degree days” – a measure of cumulative daily heat accumulation above a crop-specific minimum threshold, over a whole summer.
For example, barley is a cold-hardy species that can begin to sprout at temperatures as low as 32 F, but the rate of its growth is still heat dependent. If the average temperature on a given day is 50 F, 18 degrees above the barley threshold, that day counts as 18 growing degree days; a day at 60 degrees would count as 28. Barley will not reach maturity until it has experienced a total of about 2,500 growing degree days above 32 F – a goal that could be reached in about 138 days at 50 F, or 89 days at 60 F.
The calculation changes for the other thresholds. Broccoli, cauliflower, cabbage, and Indiana wheat will not grow unless temperatures exceed about 40 F. “Hot” crops like corn and tomatoes are even more difficult, with a 50 F threshold ; for these plants, a day at 60 degrees represents only 10 degree-days of growth. These crops have been almost entirely beyond the reach of Alaskans except in greenhouses.
In the past, I might have expected only about 850 growing degree days above a 50 F threshold here in Fairbanks in a typical summer, a far cry from the roughly 1,500 that corn would have needed to produce mature ears. But by the year 2100, my grandchildren could anticipate 2,700 growing degree days each year above a 50 F threshold – more than enough to harvest sorghum, soybeans, cucumbers, sweet corn and tomatoes.
We are also likely to see huge changes in potential perennial crops due to our loss of winter cold. Many gardeners are familiar with USDA plant hardiness zones, which are based on the coldest average winter temperature for a given area. Using the same categories as the USDA, we projected Alaska hardiness zones.
The dramatic changes in these maps provide insight into the depth of climate change in the Far North. Historically, my Fairbanks home is in zone 1 or 2. By the end of the century, it should be in zone 6 — the current zone in places like Kansas and Kentucky.
Food security and supply chains
Only 5% of the food we eat in Alaska is grown or raised here. Lower 48 expeditions travel great distances to reach our state and its scattered communities. Alaskans are vulnerable to supply chain disruptions when a single barge fails to arrive or a road is blocked.
Growing more fresh food here would help Alaska economically and nutritionally, but it won’t happen automatically. To achieve significant long-term increases in agriculture, the Alaska Food Policy Council recommended creating a proactive state-funded nutrition education program, developing more food storage infrastructure , to provide financial incentives for the expansion of agriculture and to teach residents northern farming methods. The council’s research suggests that the state could reap major benefits from investments in training, technology, support for clustered businesses such as packaging and storage, and programs to foster an agricultural culture.
A tool for gardeners and farmers
To make the results of our modeling available to home gardeners and rural villages, we have created an online tool, the Alaska Garden Helper, and a fact sheet. Alaskans can select their community, decide which of the above questions to explore, and choose the temperature thresholds they care about, from “hard freeze” (28 F or -2 C) to “hot crops” (50 F or 10 C) .
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The tool includes brief explanations of unfamiliar concepts such as growing degree days. It also includes lists of potential crops such as barley, beans, cabbage and maize, each with minimum values taken from the published literature, for the length of the summer season and the growing degree days needed to that this culture succeeds in maturing.
Nancy Fresco, SNAP Coordinator, Faculty of Research, University of Alaska Fairbanks
This article is republished from The Conversation under a Creative Commons license. Read the original article.