Assessing Delaware’s changing climate

If temperatures continue to rise, by the end of the century, Delaware's climate could resemble that currently experienced in the Carolinas. Today, the impacts of climate change can already be seen and felt in rising sea levels, dangerous heat waves and heavy precipitation.

This is evident in communities like Lewes and Reedy Point, where flooding can occur in low-lying roadways even on sunny days. In Lewes, minor tidal flooding occurred on average about six days per year in the 1980s. Today, it's closer to 41 days per year, a dramatic increase over roughly 40 years. With sea level rise accelerating in the region, this frequency is expected to increase substantially in the coming decades.

To help understand how climate change might impact Delaware in the future, the University of Delaware's Center for Environmental Monitoring and Analysis (CEMA) completed a comprehensive assessment of different climate change scenarios for Delaware in the Climate Change Projections for 2025 report.

Those future projections are classified into scenarios ranging from intermediate to extreme levels of climate change. The report is broken up into sections and looks specifically at temperature, sea-level rise and precipitation.

Kevin Brinson, director of CEMA and Delaware State Climatologist, said the sea-level projections were particularly eye-opening.

"Essentially, over the next, say, 30 years, we'll see about the same amount of sea level rise as we saw over the last 100," Brinson said. "That's obviously a big problem for a state like Delaware. With an accelerating sea level rise rate, the issues that we're running into and that we are already beginning to see are going to increase significantly."

Tina Callahan, associate director of CEMA and assistant Delaware state climatologist, said that winter precipitation showed a statistically significant increase.

"Precipitation projections show an increase in annual precipitation by mid-century, with the winter season showing the strongest upward trend," she said.

Regarding the temperature increase, Brinson said it's important for people to truly grasp what it could mean.

"It could be a very different temperature than what we experience today," Brinson said. "That doesn't mean we're not going to get cold weather anymore, and it doesn't mean that we're not going to have snow. But it means that, on the average, by the end of the century, our annual temperature patterns will look a lot more like the southeastern coast of the United States than what it looks like today."

To generate the projections, Callahan said the researchers reviewed several climate models adjusted for Delaware and used the latest international and national climate reports to assess the state's future climate.

The researchers also examined historical data to assess how the model data matched their observed records and to quantify the degree of alignment.

"We wanted to validate the data," Callahan said. "Then we took that result and looked at the future projections."

The authors of the report were Callahan and Brinson, as well as John A. Callahan, Daniel Leathers, Matt Shatley, Chris Hughes and Emmanuel Olamiriki.

Funding for the study was provided by the Delaware Department of Natural Resources and Environmental Control (DNREC) Division of Climate, Coastal and Energy. Delaware Technical Advisors provided advisory support, and the scenarios from this report will be used to support the state's Climate Action Plan and future decision-making throughout the state.