Professional Practice

Smart Policies for a Changing Climate: Natural Systems

Natural systems—or ecosystems—are critical for humans and all forms of  life on the planet. Many of  the problems we currently face—flooding, urban heat island effect, air and water pollution, coastal erosion, groundwater-related subsidence—are the direct result of  either ignoring or trying to engineer our way around natural systems. On the other hand, designing and planning in concert with natural systems promotes resilience, capitalizes on the multiple benefits provided by natural systems, and provides greater long-term return on investment. This natural systems approach should be incorporated in site, community, and regional planning and design, and applied to retrofit and rebuild projects and new development.

Design and planning solutions should also address plant and animal habitat to ensure these living communities remain resilient and productive in the face of climate impacts. Healthy and intact natural systems are inherently resilient. When climate and habitat changes are slow and gradual, plants and animals can relocate through their natural life cycles, e.g., plant seeds spreading naturally and animals moving with food and water sources. However, in the face of  
rapid climate change and human disturbance, catastrophic loss of  species is possible—such as the widespread die-off of temperate tree species in the western states. Design and planning strategies must anticipate and seek to mitigate loss of  species through active support.

The following are key design and planning strategies, followed by policy recommendations, that benefit from and support natural systems:

Design and Planning Solutions

Incorporate green infrastructure into all new and existing urban and suburban development. The term “green infrastructure”—also called the “sponge city” approach—refers to the use of  trees and vegetation in addition to permeable hard surfaces to capture, infiltrate, and clean stormwater. Beyond stormwater management, green infrastructure also provides significant additional benefits including air cooling and cleaning, reduced building energy use through shading, air cooling through evapotranspiration, enhanced aesthetics, and public health benefits. Key design and planning elements of this nature-based approach should include the following:
- At street level, reduce paved areas and maximize incorporation of trees and vegetation supported by healthy soils, including bioswales and raingardens.
- Maximize use of green (vegetated) roofs for stormwater capture and air cooling / cleaning benefits.
- Maximize use of porous pavement technologies to support natural hydrology.
- Use cisterns for capturing and enabling reuse of excess stormwater for irrigation, etc.  

Prioritize preservation and enhancement of tree canopy. Tree canopy cover directly correlates to reduced urban heat island effects, reducing the effect of  heatwaves and reducing emissions from cooling loads.  Tree cover is also correlated with air quality improvements that improve public health outcomes.

For all trees and vegetation, follow best practices for planting and maintenance.

Preserve existing open space and parkland in community and regional planning. Recapture part or all of  abandoned brownfield and grayfield sites for green/open space

Protect, expand, and/or restore natural systems, including wetlands and adjacent upland areas, that provide buffers along coastlines and inland waterways. Maintain setbacks from streams to protect watershed function and quality.

Limit or prohibit building in floodplains. (See policy recommendations for vulnerable communities).

Plan “gray” stormwater infrastructure, i.e., engineered systems, thoughtfully and sustainably in concert with natural green infrastructure systems.

Incorporate water conservation and water reuse technologies in all development and land uses.  

Protect critical water sources, including aquifers
, using best available science in concert with design and planning strategies.

Select biohabitat-supporting and pollinator-friendly native or adapted plant species appropriate to the site/region and changing climate conditions. Prioritize vegetation species that are more likely to withstand potential climate changes, including drought. In some cases, this may involve introduction of  species not currently present.

Preserve wildlands
, i.e., intact green spaces that have never been developed, to support healthy and diverse plant and animal communities.

Include greenways and wildlife corridors in regional plans to support plant and animal migration and relocation. Assess and plan for both natural and assisted migration of plant and animal species. This may include the introduction of  new species in place as well as the relocation of  seed stock and breeding animals to more suitable environments.

Policy Recommendations

Provide dedicated, ongoing funding for green infrastructure.

Require new development to retain and infiltrate precipitation on site following rigorous models based on ecosystem services, such as the SITES v2 Rating System. 

Incentivize planting of native and locally/regionally appropriate, pollinator-friendly, and drought-tolerant (where appropriate) vegetation, along with corresponding reduction of  turf  areas, through direct incentive payments, tax credits, and/or water-use charges.

Adopt a green space plan
to prioritize retention of  existing green space and identify opportunities to create/capture new green spaces. The plan should address open space/recreation area inequities across communities.

Adopt a national urban and suburban tree planting strategy
, based upon state and local models, with specific tree canopy goals, incorporating best practices for enhanced tree health and longevity. Incentivize long-term maintenance and planning, and provide funding mechanisms. Plans should also address reforestation of  areas devastated by flood and fires.

Incentivize development that retains existing native and locally appropriate vegetation and fosters biodiversity while managing or eliminating invasive plant species.

Require planting of native and locally appropriate, pollinator-friendly vegetation
on state and local rights-of-way, around public buildings, and on other publicly-owned land and civic spaces.

Adopt a national water protection and management strategy
that is regionally calibrated for careful capture and treatment of  stormwater with protection of  subsurface waters.

Prioritize protection of critical water sources
; restrict or prohibit development that puts critical sources at risk of  depletion or degradation.

Incentivize or require water conservation and reuse technologies.  

Protect wildlands
. Protect already fragmented migration corridors from further degradation.

Incentivize regional planning and development that assesses climate change risks to biodiversity and incorporates/enhances regional plant and animal migration paths.

Incentivize the use of soil management practices
that build soil health in urban, suburban, and rural settings.

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