This article provides a brief overview of land-use challenges posed by the increasing severity of climate changes on Earth. Two landscape-level strategies are explored here: Microclimate development and high biodiversity food systems. The article is of particular relevance to architects, builders, farmers and those who work with land. Context Change Is The Earth orbits the Sun at distances that vary by 3,000,000 miles. Volcanoes explode, ice fields melt, sea vents open and close, gasses continually exchange between rock and plants, ocean and atmosphere.
Plants and animals adjust to these dynamic conditions by migrating across land and sea, following their preferred conditions and adapting when they are not available. Our planet's climate is never constant - nor has it ever been. Human use of climate-altering technologies is only one factor in Earth's climate stability. Much larger patterns, geological and galactic in nature constantly force the climate of the earth to change, even without human manipulation. Climates change - it's what they do. Accurately engaging the issue of 'global climate change' requires an understanding that the Earth's climate has never done anything but change. With this in mind we move forward knowing that if human life is to continue on Earth, it will be adaptive and always plan for change. Good design is design for change. Good design must be structurally diverse and not depend on any single element for its overall success. Good design harnesses the forces of evolution and includes both the built and biological environment. This article briefly overviews strategies for developing biologically adaptive, intentional ecosystems (permacultures) and climate-buffering landscapes (microclimates) in which humans can build homes, produce food, and live well.
Design for Change
From ice-core samples that trace earth's climate millions of years to recent computer models of current patterns, evidence reveals that climate change is occurring more rapidly today than in thousands of years. Research indicates that the climate has been unusually stable for the past 10,000 and even more so for the past 100 years. Today's climate change challenge is clear: Design and develop a cultural landscape (built and biological) that will be stable within a wide range of conditions. What specific challenges should we design for? These include: longer droughts, hotter summers, colder winters, higher winds, increased pest success, heavier precipitation, earlier and later frosts, and other irregularities (which have always tested humanity's ability to thrive and survive on this planet).
Specific Climate Challenges
High performance landscapes and buildings are designed to meet the following characteristics of Earth's changing climate. Many of these challenges are already occurring in the New England:
• Precipitation via disastrous forms (e.g. high volumes of rain, snow, hail)
• Increasing likelihood of soil erosion by flooding
• Increasing heating and cooling needs
• Increasing severity and probability of high wind events
• Increasing overall success of pests
• Decreasing influence of pollinators
• Increasing likelihood of drought conditions
• Increasing likelihood of annual crop failure due to spring flooding
• Increasing water demand
• Increasing extremes of aridity and humidity
• Decreasing water table heights
• Increasing sea levels
• Increasing probability of early flowering and fruit-set, and consequent crop failure from frost damage
• Increasing failure of perennial crops due to reduced snowpack on the ground surface
Neither predominant agricultural models nor common housing and transportation systems are designed to withstand significant climate changes. These human systems will either adapt to changing conditions, or suffer increasing system failure. Land developments that intentionally adapts to these changes employ the following components among others:
1. Microclimate development including windbreaks,
snow-retaining hedgerows, thermal mass via water and stone, and sun-trapping vegetated and/or built arcs. These systems provide a buffer against regional climatic stresses by localizing climate at the site level.
2. High biodiversity of crop species from neighboring
warmer and colder climate zones (U.S.D.A. hardiness zones +/- 2 zones). Such polycultural diversity supports the resilience of the farm system at the species level, and the adaptability of crop genetics at the varietal level. This genetic complexity helps revive the loss of crop diversity caused by monoculture in the 20th century while adding to the abundance of foods we have to choose from.
A microclimate is any discrete area within a larger area of differing climate. They usually occur close to the surface of a material, commonly earth, a building façade or vegetation. They occur in a nested manner at all scales and over various periods of time. Microclimates exist unintentionally in “nature,” but good design creates microclimates intentionally. Microclimates occur over space and time. They are dynamic phenomena emerging and disappearing within a site - not a static feature of a site. They are a process, not a thing. Since cold is a limiting factor (along with light) in producing food and sustainably inhabiting the New England landscape, developing warm microclimates is the priority. Cooling strategies, however, will likely become increasingly important, especially in southern New England, if conditions continue to warm.
Optimized microclimates can result in the following:
• Lower active energy needs for buildings: less fuel, less cost, less pollution. Example: Passive solar house within a passive solar landscape.
• Longer growing seasons relative to the surrounding
environment. Example: Climate-designed garden spaces that stay frost free for weeks longer in the spring and fall than adjacent areas.
• Higher yields from plants and animals - better growing conditions. Examples: Warmer environment
for heat-loving crops; cool-shaded spaces for domestic animals in the hot summer; Wind sheltered spaces for animals and buildings.
• More enjoyable, lower stress and healthier human habitats. Longer outdoor living season; more fresh air; more contact with water, plants, living systems; and greater physical activity and mental stimulation. Example: Outdoor living spaces optimized to be cool in the summer, warm in the winter.
Microclimate Development Strategies
The first step in crafting beneficial microclimates is proper site selection. Some landscape features cannot be changed at all or only to a small extent. These usually include: relative location to surrounding landscape (elevation, topography, etc.), aspect, slope, groundwater table, bedrock exposure, etc. Only when selecting a site can these primary features be considered and selected for and against. It is helpful to map the various climates on a site to understand where optimal locations are for all developments. See Figure 1 for an example of microclimate site analysis that aids in this process.
The second step in localizing your climate is site design. Once a site has been chosen a handful of strategies, planned for and implemented carefully, can optimize the existing climate of the site to more fully meet the needs of the site's inhabitants. Please refer to figure 1 and 2 for clarifications of the concepts written below.
Design of warm microclimates checklist:
a. South - southwest = warmest
b.Consider orographic (elevational) weather effects
2. Slope/Vertical Space Harvesting: See Figure 2 for an example of a vertical space-harvesting garden layout
a. The further poleward the steeper the slope should be to capture the most solar energy
3. Bowl - solar arc/sun trap
a. Utilize energy-harvesting forms
4. Minimize radiative losses - provide cover
a. Nighttime losses of heat are the most difficult to avoid
a. Buffer and deflect, create eddies, preserve and enhance hedgerows
b.Still air = key for human comfort in cold climate
a. Stone and water are the primary heat-retaining materials
7. High absorption (low albedo)
a. Utilize color effectively
8. Time your microclimate
a. Design for a particular time of day and year, usually whenever limiting factors are most present
Examples of microclimate-creating features of a place are: hills, fields, trees, cliffs/stone, gullies, ridges, groundwater, ponds, lakes, roads, walls, lawns, roofs, courtyards. Employing such features in the development of climate-protected spaces is more effective than attempting to create new microclimates from scratch.
Of primary importance for increased food security and regional sustainability is developing diverse and flexible food crops. Climate changes can deliver periods punctuated by both extreme heat and cold within the same year. The following strategies highlight
the benefits of high biodiversity polycultural food systems.
Early and late frosts, intensifying drought, heat and cold, and other stresses (see the above list) select against certain crops. A broad range of species with different flowering cues and hardiness capabilities is insurance against poor fruit-sets, pollination failure and other problems due to capricious weather. Genetic diversity in species and variety is fundamental to a resilient ecological system.
Developing innovative new cross breeds also helps to ensure resiliency of food systems. For example, crossing a sweet cherry (Prunus avium) that crossed with a Nanking cherry (Prunus tomentosa) can create a next-generation cross that flowers like the Nanking cherry (late, thus avoiding the killing late spring frosts) but has the larger, sweeter, and more marketable cherry.
Cold Hardy Crops
Some apples and native plums can withstand 45 degrees F. or colder (depending on rootstock). Other plants share equal hardiness like Swiss stone pine, cornelian cherry, Siberian sea berry, Korean nut pine, and maralroot. Propagation and distribution of cold hardy species will assist in providing food security to the Earth's colder climates.
Warm Hardy Crops
Rapidly warming trends could outpace the agility of current agricultural systems. In a world of rapid climate change a durable farming system would plan for temperatures up to 10-15 degrees warmer or colder. Imagine Zone 4 becoming just 10-15 degrees warmer (an average low of -10 F): A diversity of bamboos, palms and bananas could be grown. The most luscious of peaches, nectarines, goji berries, Japanese raisin trees, ume plum trees (source of umeboshi, a fermented food in Japanese cuisine and medicine) could potentially also be grown.
Planning for change, instead of resisting it, has the power to turn problems into solutions. We can endlessly debate the causes of global climate change or we can design for it. Why not view the inevitable changes of Earth's global climate as a call to action and as a challenge to increase biological diversity and ecological resiliency? We can face this challenge squarely and allow it to focus our minds, communities, and our creative abilities on the development of better techniques for living on this planet.