I agree with the motto: Don’t let perfect be the enemy of good. So the goal today is a very good introductory discussion on some of the most important climate change topics for Door County gardeners and naturalists.
The Changing Growing Seasons
The first issue is the changing growing seasons. Warmer temperatures have clearly extended the growing season, allowing gardeners to plant earlier in the spring and harvest later in the fall. This also allows us to plant new varieties that have become viable in this region due to this shift in temperature and humidity levels.
Now we can see this statistically in the 2023 Hardiness Zones Map, released by the USDA. They updated their Plant Hardiness Zone Map (PHZM) for the first time since 2012, and it is now an essential tool for gardeners and growers to determine plant viability by location. Just insert your zip code at the top. https://planthardiness.ars.usda.gov/
The first improvement is Enhancements and Accuracy: It was developed in collaboration with Oregon State University’s PRISM Climate Group; the 2023 map offers improved accuracy and detail over previous versions. E.g. Green Bay is now 5b, and most of lower Michigan is 6a with a little 6b in the far southeast. One thing I find fascinating is that we here in Door County have our own little 6a square… It’s little, but it’s there. More on that later.
The second improvement is the Interactive Online Access and Features: Previous maps were accessible online, but this one features an interactive GIS-based format, and has been expanded to include a “Tips for Growers” section. GIS stands for Geographic Information System, which is kind of like a four dimensional map or data source. And this is how they were able to be so specific. You can download much finer maps for your state and county than ever before.
The third improvement is in the Data and Methodology they used: It’s based on 30-year averages of minimum winter temperatures and data from over 13,000 weather stations, offering finer resolution, especially for rural places like Alaska.
Next, the Usage and Impact: This map is a critical tool for approximately 80 million American gardeners and growers, as well as for scientific researchers and crop insurance standards.
Finally, the Zonal Adjustments and Climate Insights clearly show that some areas are becoming warmer zones. Now, the USDA doesn’t directly attribute these changes to global climate change, but common sense allows us to add this to the mountains of other data.
Pest & Disease Pressure
The second dramatic shift due to climate change is Increased Pest and Disease Pressure: The milder winters and longer growing seasons have led to the rise of new pests and diseases previously uncommon in the Midwest, affecting both native and cultivated plants. But we don’t need anyone to tell us that the spread and intensity of pests and diseases in the Midwest is impacting gardening and agriculture.
The increased temperatures and changes in precipitation patterns are two main drivers of this shift; they facilitate the growth and distribution of new, clearly different pest species by providing a warmer and more humid environment. However, extreme levels of temperature and precipitation can also hinder some pest species by destroying their eggs and larvae. So it’s not as simple as it might seem, but this complex interaction explains why many pests are migrating from tropical to more temperate areas, seeking optimal conditions for growth as these regions warm up, but not too much and not too dry.【22†source】.
My bee club, the Door County Beekeeping Club, recently invited a crops consultant who advises farmers, including the big consortiums, when and what to spray for the pests and crop health. Mark told us that they are seeing different pests, and seeing them earlier than before. Farming and gardening is already hard enough.
Research highlights the movement of crop pests and diseases towards the earth’s poles at an average of 3 km a year since 1960, as global temperatures have risen faster. So that means that the pests and diseases of Northern Illinois are now regularly our problem too.
I didn’t find any data yet, but I can’t help wonder if the Emerald Ash Borer didn’t accelerate its devastation of so many of our trees because of these better conditions. I did read that diseases such as tar spot, a fungal disease causing significant yield losses in maize, were detected in the US for the first time in 2015, illustrating the shift of typically tropical diseases into more temperate zones. And logic suggests it will migrate north. Other pests and pathogens, like the southern pine beetle and wheat rusts, are also expanding their geographical range in response to climate change, posing new challenges for Midwest agriculture【22†source】.
Mark told us about some farmers who lost their wheat crop due to a wheat worm that surprised them early in the season last year. It was especially sad because they were sitting in our bee meeting. (They’re wonderful beekeepers, by the way.) So we see the effects of these shifts in our community.
We just don’t know exactly what this will lead to. For example, changes in CO2 levels can make plants more palatable to some pests, such as aphids, by increasing the soluble carbohydrates in the plant’s phloem tissue. Is this why the japanese beatles devoured my roses last year? I tried to manage my control, but one day they just took over. So was it higher CO2 levels? I don’t know because this is not uniformly beneficial to all pests, as some plants may allocate increased carbon towards the production of secondary metabolites that deter pests【23†sourcea】.
All I know for sure, is I need to be more informed before my roses start flowering. We should take proactive measures to manage the problem and maintain the health and productivity of gardens and crops in the region as soon as possible. It would be so much easier if we just knew what was coming: The devil you know is better than the one you don’t.
Water Level Fluctuations
Next is Water Level Changes: Lake Michigan has always fluctuated, but we have seen rapid changes in precipitation patterns and increased evaporation rates in recent years, leading to fluctuating water levels that can affect garden planning, waterfront properties, flooding one year and dry conditions the next.
Climate change is leading to warmer and wetter conditions in the Great Lakes region, but its effects on water levels are complex and uncertain. Water levels are influenced by a combination of precipitation, evaporation, and runoff from surrounding lands. The Great Lakes have seen periods of both record high and record low water levels in recent years. For instance, after a period of low water levels from 1998 to 2013, Lake Michigan and the other Great Lakes experienced rapid rises to record highs between 2017 and 2020, driven by high precipitation and below-average evaporation【29†source】【30†source.
The water level of Lake Michigan, as of March 15, 2024, is reported to be 578.74 feet above chart datum (IGLD 1985), which is approximately 15 inches above the chart datum for Lake Michigan-Huron. This level represents a 1-inch decrease from the previous year at the same time and is 3 inches above the long-term average for March. It is also noted that Lake Michigan-Huron is expected to rise by about 2 inches by April 15, 2024【5†source】. But Sturgeon Bay/Green Bay, right in front of my house, seems very low. Birds are resting on islands not seen recently and our beaches are much bigger. So once again, it’s complicated.
These fluctuations have practical implications for communities around the Great Lakes. High water levels can lead to shoreline erosion, property damage, and flooding, impacting both natural and human-made environments. For gardeners, the variability in water levels, combined with changing precipitation patterns, may necessitate adjustments in plant selection, garden location, and water management practices to mitigate the effects of both flooding and drought conditions【31†source】.
The rapid transitions between extreme high and low water levels are becoming the “new normal” for the Great Lakes region, driven by a mix of global climate variability and regional hydrological cycle components. This includes increased precipitation, potential periods of high evaporation, and unusual climate events like extreme cold air outbursts. These factors put the region in uncharted territory, with significant implications for water management, agriculture, and community planning【31†source. I believe in data, like the scientists, but what they’re saying doesn’t look like the water in front of my house.
And if we look at other parts of the country, like the Northeast, the situation is very different. Margaret Roach, host of the wonderful podcast A Way to Garden, explains on her show how they have to manage “extreme water events.” Basically, they must manage no rain for long periods of time, then a massive storm.
So, adapting to these changes requires a comprehensive approach that considers the potential for both high and low water levels in the future (sometimes it seems like both are happening at the same time!) Communities and individuals in the Great Lakes region, including those in Door County and along the Lake Michigan shoreline, need to incorporate flexibility and resilience into their planning and management strategies to navigate the challenges posed by climate change and water level fluctuations.
Soil Health & Erosion
The next issue is Soil Health and Erosion: Extreme weather events, such as heavy rains and droughts, impact soil health, erosion, and garden sustainability. We gardeners must accept these challenges and implement complex strategies, such as rain gardens and erosion control plants, especially native perennials. We need to limit, as much as possible, tilling, a common agricultural practice. It is a major contributor to soil erosion in the Midwest, leading to the loss of billions of tons of soil. This erosion not only reduces soil fertility but also affects water quality and crop yields【38†source】. I recently watched a wonderful presentation by ????? from ???? on ?????
The variability in water levels in Lake Michigan, with record highs and lows in recent years, puts additional pressure on the shoreline, affecting both natural landscapes and human-made structures. This has led to significant erosion, particularly in areas with bluffs, shorelines, and dunes, necessitating research and management strategies that consider both natural responses and human interventions【37†source】.
Gardeners and landowners can adopt several strategies to combat soil erosion and improve garden sustainability amidst these challenges. Some of these include:
1. Using Cover Crops: Planting cover crops during off-seasons can reduce the time the soil is left bare, making it less vulnerable to erosion by wind and water. These crops also help improve soil health by adding organic matter【38†source】.
2. Rain Gardens: Creating rain gardens can help manage water runoff more effectively, reducing soil erosion and water pollution. They also provide habitat for local wildlife.
3. Erosion Control Plants: Planting native vegetation on vulnerable areas like slopes and dunes can help stabilize the soil and reduce erosion. Deep-rooted plants are particularly effective in holding the soil together【37†source】.
4. No-till Farming: This practice minimizes soil disturbance, preserving soil structure and protecting against erosion. It also helps in maintaining soil moisture and reducing water runoff【39†source】.
5. Terracing and Contour Farming: These methods can be particularly effective on sloped lands, reducing runoff and soil erosion by breaking the slope into smaller, more manageable levels.
6. Buffer Strips and Windbreaks: Planting rows of trees or shrubs can act as windbreaks to reduce wind speed and erosion, while buffer strips of vegetation along waterways can trap sediment and nutrients before they enter bodies of water.
Addressing soil erosion requires both immediate action to prevent further degradation and long-term strategies to rehabilitate damaged land. By incorporating these practices, gardeners and farmers can work towards more sustainable and resilient agricultural and gardening practices in the face of changing climate conditions and extreme weather events【39†source】.
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Embrace biodiversity by planting a variety of species, including drought-resistant native plants like coneflowers. Employ mulching to conserve water, reduce erosion, and suppress weeds. Eliminate pesticide use, focusing instead on attracting beneficial insects for natural pest control. Prioritize soil health by adding organic matter and possibly engaging in no-till gardening. Implement water-saving techniques, like using soaker hoses and choosing drought-tolerant plants. Also, consider starting a compost pile to enrich your soil with organic matter【45†source】.
Sources
https://www.wri.org/insights/causes-and-effects-soil-erosion-and-how-prevent-it
