Module 6: GI and Building Resilience For Climate Change
Module 6: GI and Building Resilience For Climate Change
Learning Objective
- Identify the mechanisms by which GI can improve climate resilience and adaptability and discuss examples of best practices.
All municipal infrastructure is designed using statistical projections of likely weather patterns. To make a building or a bridge safe from floods you need to know how high the surrounding water may rise. To build a reservoir and a dam you need to know how much water will flow into it and how much water you need. To design a sewer well you need to know that it will not flood during an average spring storm. As climate change leads to changes in precipitation rates and depths around the world, infrastructure designed for the 20th century will become obsolete. Cities that construct infrastructure pre-emptively, with projections of rainfall and heat, may end up spending too much on oversized systems. Or focus on the wrong issue altogether; planning for drought, when they should have been protecting from floods. Even the best global climate models (GCMs) acknowledge margins of error that represent trillions of dollars in infrastructure over the next hundred years.
Whether cities attempt to plan for a projected climate future or rebuild after failure, an unprecedented global reconstruction of infrastructure is likely at hand. This reconstruction is an opportunity to rethink how cities work and what they can provide for the growing number of people that call them home. Planning for this reconstruction well requires adaptable infrastructure designed not for a measured “what-has-been” but for a feasible range of “what-could-be”. This is green infrastructure’s greatest potential; a capacity for resilience that could help fortify cities against climate uncertainty while also reducing the emissions associated with development. The combination of these benefits is captured by the term “Low-carbon resilience (LCR)” (ACT, 2018). LCR focuses on solutions that simultaneously decrease GHG emissions while improving system resilience to climate change impacts. GI is a common entry point for municipalities to begin accounting for LCR in their planning decisions. Green infrastructure is a LCR entry point for local governments because GI interventions avoid or reduce the use of carbon-intensive products like concrete and steel that define grey infrastructure and require less carbon intensive construction techniques, while also improving system resilience to impacts like flooding and extreme heat temperatures. GI systems can also absorb carbon throughout their lifetime, potentially offsetting the emissions associated with their construction. A study of 28 U.S cities found that urban trees sequester an average of 2.05 t C ha-1 year-1(Demuzere et al., 2014). With proper maintenance, GI systems can become more effective with age as plant communities grow and establish (Denjean et al., 2017).
Successful design of GI systems requires a thorough understanding of local environmen