How Climate Change Threatens the Park Service's Memorials, Cabins and Battlefield Fields

NPS / Rachel Hendrix.

Cultural resources are sites, structures, objects and even landscapes that show the history of human activity or matter to a group of people traditionally associated with them. For the National Park Service they are central to protecting and interpreting the nation's heritage, including the many iconic structures in the National Capital Region. Climate change is making them harder to preserve: changing weather patterns, more pests, wood rot and pollution all speed their decay. The Park Service's page looks at three places where that shows.

Acid rain on stone memorials

According to the Park Service, more greenhouse gas in the atmosphere will worsen acid rain and sulfur dioxide gas, which damage the Washington, DC area's many stone memorials. Acid rain forms when the dust particles that raindrops gather around come from sulfur dioxide or nitrogen oxide emissions.

Many Washington buildings and monuments are limestone or marble, which acid rain attacks. Acidic precipitation and sulfuric gas dissolve the calcite that holds marble together, causing the loss of silicate mineral inclusions and an unsightly black crust. The Thomas Jefferson Memorial's columns were restored in 2004: the Park Service removed black crust from the marble and added structural supports so damaged stone would not fall. More costly work is likely for future damage, and researchers are still studying the climate and related causes of the crust. Federal limits on nitrogen and sulfur oxides have improved the acid rain problem in Washington since 1997, but rain there is still more acidic than unpolluted rain and still threatens cultural resources.

Historic buildings

Expected increases in wind, precipitation, humidity and temperature stress old buildings' foundations and materials, leading to splintering, warping and wood rot, and more intense storms raise the risk of falling trees. All park historic structures must therefore be monitored regularly to decide on repairs.

NPS Photo.

At Catoctin Mountain Park, the cabin camps built by the Works Progress Administration face a higher chance of damage. The cabins are made of American chestnut lumber, which cannot be replaced, so protecting what exists is vital. Higher humidity is speeding rot, and termites, more active in warm weather, will increasingly damage the wood. More frequent intense storms are likely to erode the cabins' foundations over the next several decades. In the Northeast corridor of the USA, heavy downpours became 71% more frequent from 1958 to 2012.

Farmed battlefields

Landscapes show visitors the history of a place, from the witness trees that were alive during the Battle of Monocacy to the rolling hills soldiers used for cover at the Battle of Antietam. Agricultural fields are notable cultural resources at both parks, and at Antietam fields and crops make up 75% of the landscape. The Park Service partners with local farmers to use the land much as it was used during the Civil War, so visitors can see the battlefield as the soldiers might have.

NPS / 4C park illustration.

Climate change adds a new fight. Irregular precipitation will leave the parks too wet some years and in drought a few years later. Some crops adapt, but sharper swings in precipitation or temperature will affect crops over the long term. Invasive species and insects are predicted to spread their range, and invasive plants may try to take over as native species struggle. Park staff are using more cover crops to make the soil healthier and more resilient and are carrying out an invasive species management plan at each site.

What visitors can do

The Park Service says there is still time to act so future park visitors can enjoy what people do now. It is preparing for and working to reduce the harm from climate change, and visitors can take meaningful steps too. The page is linked to Antietam National Battlefield, Catoctin Mountain Park, Monocacy National Battlefield and National Mall and Memorial Parks.

Sources

• National Park Service, "Cultural Resources and Climate Change," https://www.nps.gov/articles/000/culturalresources-climateimpact.htm; rewritten in hubnx's own words.