New County Report And Supplemental Research From NASA DEVELOP Reveal Alarming Potential Climatic Shifts For Virginia’s Most Populous County

FAIRFAX, Va. – Feb. 10, 2022 – Today, the Fairfax County Office of Environmental and Energy Coordination released an in-depth climate projections report in connection with the county’s Resilient Fairfax planning effort. The new report is complemented by a study from the National Aeronautics and Space Administration (NASA) DEVELOP National Program on the urban heat island effect within the county. The two reports reveal significant potential shifts in temperature, precipitation, and the frequency and intensity of severe weather events for Fairfax County in the coming 30 to 50 years.

Key findings in the climate projections report include the fact that annual average temperatures in Fairfax County are expected to rise across all seasons. The hotter temperatures traditionally associated with summer will expand into the spring and early fall months. Additionally, very hot days at or above 95 degrees Fahrenheit are projected to rise significantly from seven days per year currently to more than 36 days per year in 2050. By 2085, it is likely that most days of the summer will reach 95 degrees.

The report also notes a shift in the number of consecutive hot days, or periods when there is no relief between heat events. Historically, the maximum number of consecutive days at or above 95 degrees Fahrenheit stands at 2.6 per year. According to one scenario played out in the climate projections report, Fairfax County can expect to see up to 22 consecutive days at or above 95 degrees per year by 2085.

The climate projections report findings on temperature changes are supplemented by NASA’s study of the urban heat island effect locally. The NASA DEVELOP report, titled “Identifying Urban Heat Mitigation Strategies for Climate Adaptation Planning in Fairfax County, Virginia,” examined areas of the county experiencing hotter land surface temperatures due to the prevalence of pavement and buildings. The report found that the hottest spots in the county are densely urbanized with land surface temperatures as much as 47 degrees Fahrenheit higher than those in undeveloped forest reference areas. Urban heat islands in the county include areas such as Tysons, Annandale, Chantilly, Centreville, Springfield, and Herndon.

Along with changes in temperature, Fairfax County is projected to experience more intense precipitation events, which will amplify inland flooding. The county may see fewer rainy days overall, but higher accumulations and higher intensity when it does rain. Precipitation depth is projected to increase for all precipitation event types.

On a similar note, scientific consensus suggests that though there may be a reduction in the overall frequency of tropical cyclones in the Atlantic basin in the years to come, there will be an increase in the intensity of the storms that do occur. For smaller thunderstorms, the trend differs slightly. Currently, Fairfax County sees between 37 and 45 days of thunderstorms per year, on average. The climate projections report indicates that an overall increase in the frequency of severe thunderstorms is to be expected in the county.

“The new climate projections report is a stark reminder that we are likely to experience serious and significant changes as a result of greenhouse gases warming our world,” said Kambiz Agazi, Director of the Office of Environmental and Energy Coordination. “From stronger storms to longer stretches of extreme heat and humidity, Fairfax County is not immune to the effects of climate change and this report is a crucial piece of the puzzle as we prepare our community to be more resilient in the future.”

The Fairfax County climate projections report drills down to the local level, relying on statistically downscaled climate model data among other sources of information. Research and analysis completed by the Office of Environmental and Energy Coordination in collaboration with a team of consultants from The Cadmus Group, WSP, and Nspiregreen looked at six different climate hazards: extreme heat, extreme cold, heavy precipitation, severe wind and storms, drought, and coastal flooding.

The report includes findings on all six hazards, looking at projections for potential conditions in 2050 and in 2085. For each of the time periods, the research considered two different scenarios, one in which greenhouse gas emissions peak in 2040 and then decline in subsequent decades, and one in which emissions continue to increase through the end of the century, which is consistent with the current trajectory.

The climate projections report is the first piece of a comprehensive climate adaptation and resilience plan currently in development by the Office of Environmental and Energy Coordination. Subsequent deliverables, including a vulnerability and risk assessment and an audit of existing county policies, plans, and programs are expected to be released in the coming months. The full plan will be available for public comment later this spring. To read the full climate projections report and NASA Develop report please click here. To learn more about the Resilient Fairfax planning process, please click here.

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