Climate change in Maryland

Climate change in Maryland encompasses the effects of climate change, attributed to man-made increases in atmospheric carbon dioxide, in the U.S. state of Maryland.

The United States Environmental Protection Agency reports that the state's climate has warmed one to two degrees Fahrenheit in the last century, heavy rainstorms occurred more often, and sea level rose eroding beaches, submerging low lands, and increasing the salinity of estuaries and aquifers. The changing climate will increase flooding, harm ecosystems, disrupt both agriculture and aquaculture, and increase certain risks to human health.

Effects of climate change in Maryland

Temperature

The Maryland Department of the Environment has observed that temperatures in Maryland have "generally remained above the 1901–1960 average over the last 30 years, with warming more pronounced during the winter and spring seasons and statistically significant warming trends for each season". "Temperatures in Maryland have risen about since the beginning of the 20th century and temperatures in this century have been warmer than in any other period".
Climate models enable scientists to use mathematics and physics to create a virtual replica of Earth's climate. They also assist with making predictions about how future weather and climate events may be impacted by the greenhouse gasses in our atmosphere. According to a climate model created by the Maryland Commission on Climate Change under a scenario of low fossil fuel emissions, Maryland would experience an increase of in summers and in winter, while higher emissions would lead to warming of nearly in summer and in winter. West Maryland would experience greater summertime warming while areas on the lower Eastern Shore would experience less because of the moderating influence of the ocean. NASA projects that, by mid-century, Maryland will experience more than 60 additional days peer year above compared to the end of last century under continued increases in emissions.

Climate models project an increase in annual droughts, from about 15 days on average at present to 17 days for the higher emissions scenario and a smaller increase under the lower emissions scenario. Furthermore, a month-long drought can be expected to occur every 40 years and may increase to every 8 years in 2100 under the higher emissions scenario. At the same time, average annual precipitation is projected to increase over the next century, particularly during winter and spring, potentially making flooding events in urban areas more frequent and expanding flood hazard areas. "Rising temperatures will melt snow earlier in spring and increase evaporation, and thereby dry the soil during summer and fall. As a result, changing the climate is likely to intensify flooding during winter and spring, and drought during summer and fall".

Sea levels

Sea level in Maryland rose by in the 20th century, partially because the land is sinking as a result of slow adjustments of the Earth after the last ice age. While varying by less than 4 inches over 2,000 years, during the 20th century the ocean began to rise steadily again because of climate change influenced by human activities, causing the warming ocean to expand its volume and glaciers to lose melt waters to the sea. "Sea-level rise is very likely to accelerate, inundating hundreds of square miles of wetlands and land. Projections that include accelerating the melting of ice would increase the relative sea-level along Maryland's shorelines by more than 1 foot by mid-century and 3 feet by late century if greenhouse gas emissions continue to grow". The effects of accelerated sea-level rise are already observable, including shoreline erosion, deterioration of tidal wetlands, and saline contamination of low-lying farm fields. "As sea level rises, the lowest dry lands are submerged and become either tidal wetland or open water. The freshwater wetlands in the upper tidal portions of the Potomac, Patuxent, Choptank, and Nanticoke rivers build their own land by capturing floating sediments, and they are likely to keep pace with the rising sea during the next century." Coastal wetlands on the Eastern Shore, particularly in Dorchester and Somerset counties including the Blackwater National Wildlife Refuge, have locally increased the rate of relative sea-level rise, contributing to severe wetland loss. Port facilities in Maryland, primarily Baltimore, are also susceptible to increased flooding, with 298 acres (or 32 percent) of the overall port facilities in the state impacted by 2100. Storms and sea level rise also contribute to beach erosion, with occurs 150 times faster than the rate of sea level rise. The United States Geological Survey estimates that Assateague Island is "very likely" to be broken up by new inlets or lost to erosion if sea level rises two feet by the year 2100.

In November 2020, NASA reported that Annapolis had 18 days of high-tide (non-storm-related) flooding from May 2019 to April 2020, an increase over 2018's 12 days, and higher than the 1995-2005 average of 2 days annually. The increase is attributed to sea level rise caused by climate change. Resultant flood damages caused local businesses to lose as much as $172,000 a year. On Naval Academy grounds, seawater came out of storm drains, with McNair Road and Ramsay Road flooding 20 times in 2020 and more than 40 times each in 2018 and 2019. Adaptation approaches such as seawalls and building up the height of roadways and athletic fields are predicted to last only a few decades. High-tide flooding is also known as tidal flooding, sunny day flooding and nuisance flooding.

Homes and infrastructure

In 2003, storm surges from Hurricane Isabel in the Chesapeake Bay flooded downtown Annapolis, North Beach, and several communities on the Eastern Shore, causing more than 1.27 million homes in Maryland to lose power — the worst outage Maryland had ever seen — and about $462 million in damages. A 2008 report from the Maryland Commission on Climate Change found that the destructive potential of Atlantic tropical storms and hurricanes has increased since 1970 in association with warming sea surface temperatures, and that rains and winds from hurricanes were likely to increase as ocean waters warm. On Maryland's Eastern Shore, Ocean City and other developed areas are very susceptible to rising sea levels. As wetlands and barrier islands that protect rural communities from the ocean become more inundated, damage from extreme weather events will increase. The estimated loss of infrastructure and cultural assets from rising sea levels at Assateague Island National Seashore alone, for example, could reach as high as $141.9 million.

"Although hurricanes are rare, their wind speeds and rainfall rates are likely to increase as the climate continues to warm. Rising sea level is likely to increase flood insurance rates, while more frequent storms could increase the deductible for wind damage in homeowner insurance policies". A March 2019 study by the First Street Foundation found that Maryland had already lost over half a billion dollars in property value because of tidal flooding linked to sea level rise.

Ecosystems

Climate change poses a threat to bird species that depend on high elevation habitats that have been greatly reduced in size, such as the northern saw-whet owl and golden-crowned kinglet. It also impacts birds that reside in coastal marsh habitats during their nesting season, including rails and sparrows, through sea level rise and severe weather events such as storms and tidal surges. "The most vulnerable marshes along Chesapeake Bay are inhabited by great blue heron, bald eagle, American black duck, and snowy egret. The marshes near Ocean City and Assateague Island provide forage for shorebirds, such as sandpipers and plovers, and several species of ducks and geese spend the winter in these marshes". In addition to impacting habitat availability, climate change can directly affect the timing of prey availability through species abundance and distribution. For example, a decrease in horseshoe crab populations has led to a decrease in ruddy turnstones, with interacting effects related to the avian bird flu