Chesapeake Bay Cleanup Will Account for Climate Change

On Friday Governor Ralph Northam joined Maryland Governor Larry Hogan, Virginia Delegate David Bulova, Environmental Protection Agency Acting Regional Administrator Diana Esher, and the other representatives from the Chesapeake Bay watershed states at a meeting of the Chesapeake Executive Council to sign a directive that commits the Chesapeake Bay Program to addressing the threats of climate change.

In the 2014 all the parties signed the Chesapeake Bay Watershed Agreement, where the EPA set a limit for release of nutrients into the Chesapeake Bay watershed. This limit was called a TMDL at the time and now is called the Chesapeake Bay Clean Water Blueprint. Under the most recent revision to the blueprint, the Chesapeake Bay model called for about 25% reduction in nitrogen, 24% reduction in phosphorus and 20 % reduction in sediment from the “base case 2011 levels.”

 The reductions in pollution were then partitioned to the various states and river basins based on the Chesapeake Bay computer modeling tools and monitoring data. Each year, Virginia, as well as the other Bay jurisdictions, report information about implemented practices to the EPA, which takes the information and runs it through the Chesapeake Bay Watershed Model. The results estimate the amount of nitrogen, phosphorus and sediment that would make it to the Bay under average conditions. By comparing the model results across time, EPA can see the expected collective impact of our actions under the implementation plans.

However, with climate change, conditions veer away from the average conditions underlying the model assumptions. Let’s be honest, no matter what mankind does, in the next couple of decades the expected impacts from climate change are going to happen. At this point climate projections for our region forecast that on average, precipitation in the region is projected to increase by around 8% by 2040, and temperature is projected to increase by about 1 °C further.

“Because warmer air can hold more moisture, heavy rainfall events ...are projected to increase in frequency and severity as the world continues to warm. Both the intensity and rainfall rates of Atlantic hurricanes are projected to increase with the strongest storms getting stronger in a warming climate. Recent research has shown how global warming can alter atmospheric circulation and weather patterns such as the jet stream, affecting the location, frequency, and duration of these and other extremes,” says the Fourth National Climate Assessment.

To respond to climate, change the Chesapeake Bay models will have to incorporate more precipitation and more severe storms. It is stormwater that delivers the pollutants to the Chesapeake Bay. Our mitigation efforts must consider increased storm intensity and flooding frequency. Our mitigations, called “Best Management Practices” must be robust and be able to function in stronger storms.

So, the Chesapeake Executive Council has committed to increase the resiliency of the watershed, including its living resources, habitats, public infrastructure and communities, to withstand adverse impacts from changing environmental and climate conditions. To respond to the growing body of science documenting the impacts of climate change and the urgent need for action, the Executive Council has agreed to build upon previous commitments and hasten their response. Directive No. 21-1 Collective Action for ClimateChange calls for addressing the threats of climate change in all aspects of theplan to restore the Chesapeake Bay and its watershed:

• Prioritize communities and habitats most vulnerable to ever-increasing risks.

• Apply the best scientific, modeling, monitoring and planning capabilities of the Chesapeake Bay Program.

• Connect Chesapeake Bay restoration goals with emerging opportunities in climate adaptation, mitigation, and resilience.

As the Chesapeake Bay Foundation stated: “Climate change is a real and imminent threat to the Chesapeake Bay. Water temperatures are warming. Sea levels are rising. Record levels of rainfall, like those in 2018, are expected to become more regular. Scientists agree these changes will make Bay restoration harder, requiring additional reductions in nitrogen and phosphorus pollution by 2025.”