This week's post and the next two #SummerScienceFridays will aim to answer the question: what do resilient communities look like?
Since there are many different ways to address this question and many different answers, this week we will start by focusing on what community resilience means, especially in the face of a changing climate, and by identifying the specific threats that climate change poses to our Southern California communities. Next week, we’ll discuss community-level resilience strategies in urban environments and the potential for these strategies to improve the quality of life and health of residents, making entire communities more resilient. Lastly, in part three, we will cover what resilience can look like on a regional scale.
What is resilience, and why is it important?
Community resilience is the ability of a community to adapt to changes, mitigate impacts and anticipate risks. Communities, like individuals, can become stronger by learning from past experiences and preparing for the future. However, when it comes to climate change, the science is telling us that the planet is experiencing something entirely unprecedented. Due to human activity, i.e. the burning of fossil fuels, global climate is changing at an unprecedented rate, causing global temperatures to become warmer on average.
So why are these fast global warming trends so concerning? Well, increased average temperatures have caused increased water scarcity, drought, more frequent fires, altered habitat, and higher persistence of invasive species. We are already witnessing these effects today, some of which present health risks, especially for children and the elderly. In Southern California, some of the effects that will impact communities include hotter temperatures, especially in urban environments, and water scarcity. The city of Los Angeles in particular is expected to become hotter, suffer from more frequent and intense rainstorms, and consequently have more disastrous flood events. Scientists and decision makers are using environmental models to begin to understand climate change and prepare our communities for its worst effects. CWH understands how important it is for Angelenos to consider these changes and envision what healthier and more resilient communities can look like.
This map from the Los Angeles Times shows the number of additional extreme heat days expected by 2050.
Here are a few facts about climate change in the Los Angeles area:
California has already warmed by 1.1 to 2 ℉ in the last century (Western Region Climate Center).
Average annual temperatures in LA will likely increase 4-5 ℉ by mid-century (The Climate Change in the Los Angeles Region Project).
Climate change in the greater Los Angeles region is going to bring higher temperatures and greater frequency of extreme heat days:
The number of heat advisory days exceeding 95℉ will increase, but warming will not affect all neighborhoods equally (with the worst heat for mountains and inland areas). Downtown LA, for example, is projected to experience about 22 of these days per year, compared to only six from 1981-2000, while Riverside is expected to experience an average of 98 heat days, up from the 58 average heat days in the same time period. (The Climate Change in the Los Angeles Region Project)
Sierra snowpack will decrease and have implications for LA County’s water supply (Sun et. al 2016):
A hotter climate will result in 48%-65% less Sierra Nevada mountain snowpack, an important water supply source (California Climate Science and Data 2015 Report). In fact, it will threaten 40% of Southern California's current water supply by 2020.
When it comes to precipitation, the average will not change much, but extremes weather events will (Swain, 2018):
A more than threefold increase in flooding events comparable to CA’s Great Flood of 1862 is expected .
Also, a smaller but still significant increase in the number of extremely dry years is likely to occur.
Sudden changes from very dry to very wet weather will become more frequent, known as “climate whiplash”.
In the face of such climate challenges, stormwater capture and other strategies for water resilience are now more important than ever.
Wildfires and mudslides:
With increasing numbers of super dry years comparable to the recent 5-year drought, California is headed towards an increase in the number of severe wildfires, an effect that can already be seen in fires like last year’s giant Thomas Fire in Ventura County (Swain, 2018).
On the other hand, extreme rain events, combined with the state’s usual earthquake activity, are likely to increase the chance of mudslides and landslides occurring.
Spring 2018 brought deadly landslides as rain-heavy winter storms led to rapid erosion in the hills of Southern California.
Mudslides can even be made more likely by wildfires, which kill trees and grasses whose roots are vital to holding soil together.
Creating resilient communities