CLIMATE SCIENCE PORTAL CLIMATE SCIENCE 101
How will Maine farmers, gardeners and consumers be effected by climate change?
While predictable weather forecasts are critically important to growers, a changing climate presents meteorologists and farmers with unprecedented challenges from less predictable weather patterns to new unseasonable extremes.
Farmers and gardeners use growing zones to know what kinds of plants they can grow. These are called plant hardiness zones. The warming climate over the past half-century has already shifted these hardiness zones north by half a zone, allowing the use of plants that used to be too cold-sensitive in some places and making it harder to grow other plants that need colder conditions.
The growing season (the period between the last frost and first frost) is now more than two weeks longer than it was in 1950, mostly due to later frosts in the fall. Longer growing seasons have allowed some farmers to report they could double-crop, while others are capitalizing on the longer growing season by planting watermelons.
Any advantages the longer growing seasons may offer Maine farmers will likely be offset by other climate-related changes such as: wetter and cooler springs, more extreme precipitation events, more intense drought conditions causing increased need for irrigation, and the northward migration of invasive pests. Crops that have done well in Maine historically may no longer thrive here as the climate continues to change. Warmer summers and increased rainfall will also pose problems for livestock such as dairy cattle and poultry.
Warmer temperatures and more days of extreme heat will negatively affect animal production and welfare. Heat stress reorganizes how bodily resources such as fat, protein and energy are used by livestock. Heat stress also reduces metabolic rates in livestock and alters animal metabolism in other ways. Growth, production, reproduction and health may all be negatively impacted by heat-stressed animals. The severity of the impacts depend on the duration and severity of the heat events.
REPORT | National Library of Medicine
ABSTRACT OF JOURNAL OF ANIMAL PHYSIOLOGY AND ANIMAL NUTRITION
© 2015 Blackwell Verlag GmbH. Heat stress effects on livestock: molecular, cellular and metabolic aspects, a review, "Elevated ambient temperatures affect animal production and welfare."
Warmer temperatures and wetter weather will increase the risk and occurrence of animal diseases, because certain species that serve as disease vectors, such as biting flies and ticks, are more likely to survive year-round under these conditions. Certain existing parasitic diseases may also become more prevalent, or their geographical range may spread, if rainfall increases.
Maine growers will need to adapt to the changing climate by adjusting the range of plants and livestock that they grow. They can play an important role in helping to mitigate challenges, for example by adopting regenerative agriculture practices such as: no or low tillage, diverse cover crops, on-farm fertility, no or minimal pesticide use, multiple crop rotation, managed grazing, etc. Such practices regenerate the health of the soil, increasing its capacity to drawdown carbon dioxide from the atmosphere while improving plant health, nutrition and productivity.
How will Maine farmers and consumers will be impacted by climate driven events beyond Maine’s borders?
According to the USDA National Agricultural Statistics Service in 2020, approximately 6% of the overall acreage in Maine was devoted to agriculture, and less than two% of the Maine workforce is directly engaged in farming. The U.S. Department of Agriculture’s most recent Census of Agriculture which covers the years 2012 to 2017, further reveals that Maine lost about 10% of its farmland over that 5-year timeframe, with a drop from 1.45 million acres in 2012 to 1.3 million acres in 2017 in the form of 573 farms (dropping from 8,173 farms in 2012 to 7,600 farms in 2017).
According Abigail Curtis in her May 5, 2019 article for the Bangor Daily News entitled “Maine is losing farms and farmland, but hope is not lost for agriculture”, based in part on analysis of the report by Maine Farmland Trust, there are also some hopeful trends over that same five year period:
the numbers of small farms (1 to 9 acres in size) and the number of farms larger than 2,000 acres both increased slightly;
“there was a 53% increase in the value of food sold directly to consumers, through farmer’s markets and community supported agriculture, etc.;”
the market for Maine grown organic products increased by 65%;
and the number of young farmers in Maine grew steadily.
While Maine’s Climate Action Plan, Maine Won’t Wait, suggests that only 10% of the food Mainers consume is grown in Maine, no one can say precisely if that baseline is accurate because the metrics and tracking system needed to make such an analysis is not yet fully functional. Nonetheless, Maine has set a goal of Maine residents eating 30% locally sourced foods by 2030. This achievement will require fundamental changes to Maine’s current food system.
As a prime example of how the impacts of climate change beyond Maine’s borders will affect Maine farmers and all Mainers: increased droughts in the Midwest typically force grain prices to rise sharply, adding to the economic challenges for livestock farmers. In some cases these challenges are forcing some Maine farms out of business, further threatening Maine’s local food supply. (MCF, 2015)
What will the impacts on wild crops such as blueberries and maple syrup be?
Recent research conducted out of the University of Maine suggests that wild blueberry fields have been warming at a rate that could have negatively impacted crop health and yields. Down East barrens, which seem to be reacting to climate change faster than the state as a whole, may be especially vulnerable. According to the researchers, blueberry plants cannot photosynthesize well at temperatures that consistently exceed 72 degrees Fahrenheit. The fact that Maine has reported record-high temperatures over the past few years could see blueberry yields struggle in the future.
Though it is still uncertain that Maine will experience more frequent droughts due to climate change, warmer temperatures will very likely exacerbate (intensify and lengthen the duration of) naturally occurring droughts. Higher temperatures cause water to evaporate more quickly, sapping liquid water from soils and plant leaves.
For this reason, the UMaine team recommends that blueberry cultivators start to explore ways to irrigate their crops, as well as implementing soil management techniques to combat water loss. These and other new management strategies will be required to ensure the long-term health of wild blueberry crops.
Climate is one of the Maine factors affecting annual yield of maple syrup through its effects on sap flow and/or sugar concentrations. Conditions prevailing during the growing season and winter prior to sap season appear to be particularly important. The optimal time to maximize sap collection is projected to advance earlier in the year--nearly three weeks earlier by 2050 compared to today. If producers adapt and shift the conventional start date of maple syrup season to early February, the current eight-week window of sap collection days in Maine may be maintained or even increased. [Source: MCF 2015]
REPORT | University of Maine
CLIMATE CHANGE PATTERNS OF WILD BLUEBERRY FIELDS IN DOWNEAST, MAINE OVER THE PAST 40 YEARS "Blueberry fields are mainly distributed in coastal glacial outwash plains which might not experience the same climate change patterns as the whole region."
Has climate change put Maine's commercial fishing, lobster and shellfish industries at risk?
Cold-water species such as Atlantic herring, winter flounder, haddock, and alewife, are migrating northward, while warm-water species such as black sea bass, green crabs are invading from the south.
Maine’s long standing lobstering heritage is at risk due to warming of coastal water temperatures. The recent boom in lobstering over the last six to eight years may seem to contradict this. However, this increase in the lobster population is temporary as it is due to the northward migration of lobsters from the south. As lobsters continue their northerly migration, soon it will be Maine’s turn to watch them disappear.
REPORT | University of Maine
Climate change is negatively impacting Maine’s coastal fisheries.
For example, scientific research suggests that the collapse of the shrimp industry in Maine is directly connected to ocean warming. Northern shrimp (Pandalus borealis) once supported a vibrant fishery in the Gulf of Maine, providing fisherpeople and coastal communities with a lucrative catch between lobster seasons. But in 2013, the Atlantic States Marine Fisheries Commission determined that stocks of P. borealis were too low to be sustainable, and a moratorium on the harvesting of shrimp in the Gulf of Maine was soon imposed. Source: Chang, Hsiao-Yun, "The Impacts of Climate Change on the Gulf of Maine Northern Shrimp (Pandalus borealis) Distribution, Reproduction, and Life" (2021) Electronic Theses and Dissertations. 3411.
Shrimp recruitment failures have been directly correlated with warming water temperatures, and the negative impact that this warming has on phytoplankton growth. Phytoplankton are a key food source for Northern shrimp.
Scientists believe that the most likely explanation for the negative impact upon phytoplankton is the thermal stratification that occurs as surface waters warm significantly. Warm water is less dense than cold water and when the temperature difference between the two is great enough, distinct layers form, with the warm water floating on the surface. As ocean water surface temperatures increase, the thermal barrier between the warm and cold layers grows stronger, impeding circulation between the surface waters where phytoplankton grow, and the cold, nutrient rich waters below. As nutrients decline, so do shrimp populations.
Ocean temperatures in the western Gulf of Maine have increased in recent years and are predicted to continue rising. This suggests an increasingly inhospitable environment for northern shrimp and the need for strong conservation efforts to help sustain the stock.
WEPSITE | NASA Earth Observatory
WARMING OCEAN SLOWS PHYTOPLANKTON GROWTH "In addition to playing a big role in removing greenhouses gases from the atmosphere, phytoplankton are the foundation of the ocean food chain."
Cod fishing off the coast of Maine has also declined. Commercially important shellfish such as oysters and clams will be negatively impacted by ocean acidification.
Climate science is increasingly important to sound fisheries management to ensure that they can adapt their activity to the changes in population.
How will climate change damage Maine's infrastructure and property values?
The Northeast has experienced a greater recent increase in extreme precipitation than any other region in the U.S. Between 1958 and 2010, the Northeast saw more than a 70% increase in the amount of precipitation in very heavy rainfall events, taxing an already stressed and aging infrastructure. Flood conditions created by increased precipitation, more frequent extreme precipitation events and wild temperature swings are all threats to public infrastructure such as roads and bridges, and private property.
Coastal areas will also see more infrastructure damage due to sea level rise. Almost 200 miles of Maine’s roads and more than 1,200 homes are threatened by coastal flooding, causing property values in many coastal areas to decline.
Source: Jonesboro/Roque Bluffs Volunteer Fire Department
ARTICLE | Portland Press Herald
AFTER NORTHEAST FLOODING, INSURANCE PROBLEMS SWAMP RESIDENTS by Bobby Caina Calvan and David Porter, Associated Press, Portland Press Herald, September 23, 2021.
ARTICLE | Portland Press Herald
COMMENTARY: HIGH-TIDE FLOOD RISK IS ACCELERATING, PUTTING COASTAL ECONOMIES AT RISK by Renee Collini, Mississippi State University, The Conversation, Portland Press Herald, July 16, 2021.