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What is climate change?

Climate change is caused by increases in gases that get trapped in the atmosphere, holding heat closer to Earth’s surface. The resulting increasing temperatures have cascading effects on ecosystems and communities.

In Maryland, our built infrastructure and natural resources can exacerbate and alleviate the impacts of climate change. Built infrastructure such as roads and buildings can increase water flow after storm events because the water cannot seep into the ground. ​This stormwater runoff can increase flooding and pollution. Buildings and infrastructure also trap heat. Urban environments can be more than 10 degrees Fahrenheit warmer than more vegetated areas. Land subsidence is also leading to increased rates of flooding, because as land sinks, sea levels become higher. Natural and built habitats, such as wetlands, stormwater ponds, and forests, can alleviate these impacts by absorbing stormwater and cooling landscapes.

Increasing temperatures, changing precipitation patterns, flooding, sea level rise, and invasive species all have an effect on the way our state’s natural resources can be enjoyed. The Maryland Department of Natural Resources is employing techniques and nature-based solutions to protect Maryland’s natural resources and the benefits they provide.

​Climate Definitions provides an overview of terms relevant to the department’s climate resilience initiatives.

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How is climate change impacting us?

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Temperature

Temperatures in Maryland have already increased by an average of 2.5 degrees Fahrenheit since the beginning of the 20th century. Increased temperatures intensify heat waves, droughts, and air pollution. They also cause a loss of suitable habitat in the Chesapeake Bay and give an advantage to invasive species. Increased temperatures also impact agriculture, recreation, and general outdoor activities.

Sea-level rise

Scientists predict sea levels will rise by 1.6 feet between 2000 and 2050. This will have dramatic impacts in Maryland, particularly on the low-flying coastal landscape and the Eastern Shore. The state already lost 13% of lower Eastern Shore marshes between 1980 and 2010, and up to 20% of coastal forest and 14% of farmland in that area could slip away by 2100. Annapolis has seen a 1300% increase in days of flooding since 1950.

Precipitation

Climate change contributes to heavier downpours. Precipitation from heavy storms has increased in the eastern U.S. by more than 25% since 1958, and 30% of rainstorms from 2007-2016 would have been in the top 1% of storm intensity in the 1950s. Scientists project a 5 to 10% increase in average rainfall here by 2050. Higher precipitation results in part from the greater amount of water vapor in the air.

Storms

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Scientists expect a greater frequency and intensity of storms due to climate change. Maryland experienced 24 weather disasters between 2010 and 2018. Coastal storms cost an average of $200 million in damage annually in Maryland in 2015, and that cost is expected to increase by $7 to $30 million each year by 2030, by $20 to $160 million each year by 2050, and as much as an additional $340 million annually by 2100.

Drought

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Though precipitation in Maryland is projected to increase, these events are anticipated to be flashier, with drier periods between larger storm events. Prolonged drought can cause soil to become dry and less absorbent, reducing agricultural yield and making the landscape more prone to flooding. Drought can also dry up small streams and decrease rainfall, increasing the salinity of the Chesapeake Bay watershed and altering habitat. In extreme cases, drought can impact drinking water supply by reducing water input into wells and reservoirs.

Wildfires

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Climate change contributes to warmer, drier conditions that increase the risk of wildfires. Although wildfires are a more serious concern in the western United States, wildfires do affect Maryland. On average, the Maryland Forest Service responds to 123 wildfires, burning about 1,780 acres of forest, brush, and grasses in a year. A small percentage of wildfires are caused by lightning, while 96% of wildfires result from human activity. The Maryland Forest Service works to reduce the risk of fires on the landscape with techniques such as prescribed burns, which remove dry forest fuels in a controlled setting.

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