Definitions and Terms

​​Our hope is that these definitions will serve as an umbrella definition for the terms to be used in funding, communication and outreach to help clarify how CCS is thinking about these terms and applying them in our own climate efforts.​

Climate Term Definitions



Climate adaptation refers to those actions taken to reduce vulnerability to the impacts of climate change, aimed to enhance the resilience of natural and human-based systems (2030 Greenhouse Gas Emissions Reduction Plan​)​

Adjustment in natural or human systems to a new or changing environment that exploits beneficial opportunities or moderates negative effects (U.S. Global Change Research Program,​)

Adaptive Capacity:


Definition from the IPCC Fifth Synthesis Report: The ability of systems, institutions, humans and other organisms to adjust to potential damages, take advantage of opportunities, or respond to consequences of climate change2. {WGII, III}
2 This glossary entry builds from definitions used in previous IPCC reports and the Millennium Ecosystem Assessment.

Climate Change:


Changes in long-term average weather patterns on a global, continental, regional, or local scale occurring as a result of greenhouse gas emissions. Increasing levels of emissions are being generated by human activities, including burning and producing fossil fuels, agricultural practices, and deforestation. As a result, heat is trapped in the Earth’s atmosphere at increased levels, causing global temperatures to rise. As temperatures rise, additional environmental changes, or climate impacts, occur.

Coastal Zone


The term "coastal zone" means the coastal waters (including the lands therein and thereunder) and the adjacent shorelands (including the waters therein and thereunder), strongly influenced by each other and in proximity to the shorelines of the several coastal states, and includes islands, transitional and intertidal areas, salt marshes, wetlands, and beaches. ... The zone extends inland from the shorelines only to the extent necessary to control shorelands, the uses of which have a direct and significant impact on the coastal waters, and to control those geographical areas which are likely to be affected by or vulnerable to sea level rise. Excluded from the coastal zone are lands the use of which is by law subject solely to the discretion of or which is held in trust by the Federal Government, its officers or agents.

Maryland’s coastal zone extends to the inland boundary of the 16 counties bordering the Atlantic Ocean, the Chesapeake Bay, and the Potomac River (as far as the municipal limits of Washington, D.C), and includes Baltimore City and all local jurisdictions within the counties. (​) Directly from the Coastal Zone Management Act of 1972.



The nature and degree to which a system is exposed to significant climatic variations. (​IPCC Report 2001​)

Intertidal Zone


Is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). Intertidal zones exist anywhere the ocean meets the land, from steep, rocky ledges to long, sloping sandy beaches and mudflats that can extend for hundreds of meters. (​)



Rivers, streams, lakes, and reservoirs with use classes other than II (Support of Estuarine and Marine Aquatic Life and Shellfish Harvesting) or II-P (Tidal Freshwater Estuary – includes applicable Use II and Public Water Supply). The geospatial data delineating tidal and non-tidal use classes can be found at the following link. Non-tidal use classes include waters that are:

  • Use Class I: Water Contact Recreation, and Protection of Non Tidal Warm Water Aquatic Life
  • Use Class I-P: Water Contact Recreation, Protection of Aquatic Life, and Public Water Supply
  • Use Class III: Nontidal Cold Water
  • Use Class III-P: Nontidal Cold Water and Public Water Supply
  • Use Class IV: Recreational Trout Waters
  • Use Class IV-P: Recreational Trout Waters and Public Water Supply



Coastal resilience is the capacity to anticipate threats, reduce community vulnerability, and respond to and recover from hazardous events and chronic stresses. (The RAFT, Link​)



The extent to which a system, asset, or the natural environment may be negatively affected or benefitted by the effects of climate change. (IPCC Adaptation Chapter, 2014)

Water Quality Impacts


A variety of factors associated with climate change have an influence on how nutrients impact the dissolved oxygen of the Chesapeake Bay. These include sea level rise, increased water temperature and increased precipitation, which generates more nutrient laden runoff. The ocean water dilution caused by an estimated increase in volume of the Bay, due to sea level rise, is predicted to benefit water quality. However, increased temperature and runoff are predicted to degrade water quality in terms of dissolved oxygen. Modeling analyses conducted by the Chesapeake Bay Program since 2019 estimate these factors will lead to a net degradation of water quality. (pulled from MD Climate Addendum pg. A-2​)


Hazard Definitions



An event that has the potential to cause fatalities, injuries, property damage, infrastructure damage, agricultural loss, damage to the environment, interruption of business, or other types of harm or loss (FEMA).

Coastal hazards include the following traditional hazards and those identified in the CZMA: flooding; coastal storms (including associated storm surge); geological hazards (e.g., tsunamis, earthquakes); shoreline erosion (including bluff and dune erosion); sea level rise; Great Lake level change; land subsidence; and saltwater intrusion… The five hazards that consistently resulted in widespread impacts across Maryland include: coastal hazards; flood; winter storm; tornado; and, wind.​

Hazard Mitigation


In a planning context, any sustainable action to reduce or eliminate long-term risk to people and property from future disasters through actions to break the cycle of disaster damage, reconstruction and repeated damage (Adaptation Framework​).



A rotating low-pressure weather system that has organized thunderstorms but no fronts (a boundary separating two air masses of different densities). Hurricanes occur at 74 mph, whereas tropical storms occur from 39-74 mph. Hurricanes with maximum sustained surface winds of less than 39 miles per hour (mph) are called tropical depressions (NOAA​).



Effects on natural and human systems that result from hazards. Evaluating potential impacts is a critical step in assessing vulnerability (Climate Resilience Toolkit)

Coastal Flooding

  • High Tide Flooding (aka sunny day flooding, king tide flooding):​ Occurs when sea level rise combines with local factors to push water levels above the normal high tide mark. Changes in prevailing winds, shifts in ocean currents, and strong tidal forces (which occur during full or new moon) can all cause high tide flooding, inundating streets even on sunny days (NOAA).
  • Nuisance Flooding: Coastal flooding that occurs at high tide and interrupts day to day activities leading to a public inconvenience such as road closures, and overwhelmed storm drains (MyCoast)
  • Storm Surge: Storm surge is the abnormal rise in seawater level during a storm, measured as the height of the water above the normal predicted astronomical tide. The surge is caused primarily by a storm’s winds pushing water onshore (NOAA)
  • Critical Infrastructure: systems, assets, facilities and networks that society relies on for economic vitality and public health and safety (US Dept of Homeland Security)


  • Duration: An amount of time used to measure rainfall intensity, such as 30 minutes, 1 hour or 24 hours.
  • Intensity: Rainfall intensity is determined as the average rainfall rate in mm/h or mm/min for specific rainfall duration and a selected frequency. (ScienceDirect)
  • Increased Storm Intensity: More heat and water in the atmosphere and warmer sea surface temperatures are increasing storm precipitation and could provide more fuel to increase storm wind speeds. Storm intensity is measured by the maximum surface wind speed or the minimum sea level pressure. (ClimateSignals)

Relative Sea Level Rise (RSLR)


The change in the level of the ocean relative to the land at a particular location. RSLR includes both global and local factors. Globally, sea level is rising due to climate change as warmer temperatures cause the thermal expansion of ocean water and the melting of land ice. Locally, sea level change is also affected by vertical land motion, or the movement of land up or down. In the Mid-Atlantic region, the land is slowly subsiding, or sinking, leading to RSLR rates greater than the average global rate (SLR Projections Guidance Document)

Saltwater intrusion


the movement of brackish water -- water with a total dissolved-solid (TDS) concentrations greater than or equal to 1,000 milligrams per liter (mg/L) -- into freshwater, including into surface waters, aquifers, and water within soils. (SWI Planning document​)



A series of extremely long waves caused by a large and sudden displacement of the ocean, usually the result of an earthquake below or near the ocean floor. The tsunami risk in Maryland is very low, and if one were to occur it is important to go inland and to higher ground. (NOAA​)

Urban Heat


Urbanized areas that experience higher temperatures than outlying areas. Structures such as buildings, roads, and other infrastructure absorb and re-emit the sun’s heat more than natural landscapes such as forests and water bodies. Urban areas, where these structures are highly concentrated and greenery is limited, become “islands” of higher temperatures relative to outlying areas. Daytime temperatures in urban areas are about 1–7°F higher than temperatures in outlying areas and nighttime temperatures are about 2-5°F higher. (EPA​)

Water quality impacts


Increasing temperature, runoff and erosion are predicted to degrade water quality throughout Maryland. Modeling analyses conducted by the Chesapeake Bay Program since 2019 estimate these factors will lead to a net degradation of water quality. (Modified from MD Climate Addendum​ pg. A-2)



Wildfires are a common occurrence in Maryland. The only natural cause of wildfires is lightning, and this accounts for only 4% of the wildfire ignitions in Maryland. The remaining 96% of wildfires are caused by humans. Maryland’s leading cause of wildfires is improper debris or outdoor burning that ignites an average of 35% of the fires each year (Maryland DNR)