Climate Variability

Our climate is responsible for many types of extreme events, and communities throughout the Great Lakes are working to become more resilient to the impacts of a variable climate. Communities should be aware of climate trends and feel empowered to plan for greater resiliency to climate impacts.


  • Global trends are more certain than regional trends
  • Natural variability plays a larger role at the regional scale.






The amount falling in the heaviest 1% of precipitation events increased by 37% in the Midwest and by 71% in the Northeast from 1958 to 2012.



  Lake Superior



Damages to Infrastructure

  • 2014 Metro Detroit flood

Health Impacts

  • Extreme heat events
  • Flooding
  • Infectious disease
  • Air quality issues

Food and Agriculture

  • Negative impacts on tree species
  • Fire hazards and wildfire

Environmental Impacts


  Michigan State Climatologist speaking to St. Joseph residents at the Master Plan kick-off meeting.


The politicization of climate variability has had the effect of making it difficult for communities to have productive conversation on these issues.  However, communities can talk about resiliency outside the framework of climate variability and its politics by focusing on other benefits of resiliency planning.  A community undergoing a resiliency planning process can improve its ability to withstand, react, and adapt to any kind of future change.  Positive environmental outcomes from this process may include;

  • a greater ability for public infrastructure systems to handle an emergency
  • improved water quality
  • better recreational opportunities.

When discussing climate variability, it is most important to discuss what is happening and could happen to a local community. Global trends with vast natural and social causes are controversial and abstract. Instead, communities should focus on areas of agreement (i.e. “flooding is bad and we should mitigate against flood damage in our community”) and “actions of no regret.”

Actions of no regret are projects and investments where the benefits are clear, regardless of the impact of climate variability.  For instance, investing in green stormwater infrastructure, such as raingardens and green roofs, reduces water pollution and beautifies the built environment. By focusing on projects that the majority of the residents can support, communities can bypass heated climate change debates and instead enact practical improvements.


  Ludington, MI


“A vulnerability assessment is a first step in climate adaptation, just as a risk assessment is an early step in risk management.” 

— Michigan DNR

Vulnerability assessments have been used across Michigan by the Land Information Access Association (LIAA). The purpose of a vulnerability assessment is to identify vulnerabilities within a community and to develop tools communities can use to foster resiliency in their policy decisions.  A vulnerability assessment looks at exposure to risk and sensitivity to risk.  Evaluating exposure to risk asks: where is the environmental risk the greatest?  Evaluating sensitivity to risk asks: who in my community is most likely to experience the adverse effects from that risk?

Vulnerability Analysis Steps

  1. Identify Sensitive Populations
  2. Identify Environmental Risk
  3. Composite Vulnerability
 A flood-damaged road near Ludington, Michigan in 2008.  (Photo by Josh Bis via Creative Commons)


Vulnerability assessments are made up of two parts – exposure and sensitivity. Exposure demonstrates the land, property, and neighborhoods that are most likely to be impacted by flooding, heat, or other severe weather. Low lying land, land near bodies of water, areas with large swaths of pavement, neighborhoods with few trees, and sections with older homes all suffer from high levels of exposure.

Sensitivity demonstrates the members of the population that are most likely to be impacted by severe weather. The most sensitive populations are the elderly, young children, people with medical conditions, those living in poverty (especially the homeless), people who work outdoors, and athletes. People who live alone, regardless of their economic status, are also at higher risk.

The Vulnerability Assessment combines the concepts of exposure and sensitivity into a single metric using mapping, as demonstrated in the following maps from the greater Ludington area:


Vulnerability = Exposure + Sensitivity