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Caused or influenced by humans; human-induced.

Also known as atmospheric pressure, it is the force exerted by the atmosphere on a given point on Earth. When barometric pressure increases, sea levels tend to fall, and when barometric pressure decreases, sea levels tend to rise. This occurs because higher atmospheric pressure exerts more force on…

Changes in average weather conditions that persist over multiple decades or longer. Climate change encompasses both increases and decreases in temperature, as well as shifts in precipitation, changes in frequency and location of severe weather events, and changes to other features of the climate…

The wearing away of land, or the removal of beach or dune sediments by wave action, tidal currents, wave currents or drainage. A combination of episodic inundation events and relative sea-level rise will serve to accelerate coastal erosion.

The invisible force around the Earth that pulls objects towards Earth’s core.

A functional unit consisting of living organisms, their nonliving environment, and the interactions within and between them. The components included in a given ecosystem and its spatial boundaries depend on the purpose for which the ecosystem is defined. In some cases, ecosystem boundaries are…

El Niño is a climate phenomenon characterized by the warming of surface waters in the central and eastern tropical Pacific Ocean. This warming disrupts normal weather patterns, leading to significant changes in global climate, including increased rainfall in some regions and droughts in others. It…

Greenhouse gases (GHGs), precursors of GHGs, and aerosols caused by human activities. These activities include the burning of fossil fuels, deforestation, land-use and land-cover change, livestock production, fertilization, waste management, and industrial processes.

The overflowing of the normal confines of a water body or the accumulation of water over areas that are not normally submerged.

The rate at which something occurs or is repeated over a particular period of time or in a given sample.

The average height of the entire ocean surface. Global mean sea level rise is caused primarily by two factors related to global warming: the added water from melting land-based ice sheets and glaciers and the expansion of seawater as it warms.

The increase in global surface temperature relative to a baseline reference period, averaging over a period sufficient to remove interannual variations (e.g., 20 or 30 years). A common choice for the baseline is 1850–1900 (the earliest period of reliable observations with sufficient geographic…

Gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of radiation emitted by Earth’s surface, by the atmosphere itself, and by clouds. This property causes the greenhouse effect. Water vapor, carbon…

High tide flooding occurs when water levels exceed heights that are calibrated to the depth-severity impact thresholds of the NOAA National Weather Service and local emergency managers to trigger public notification of impending flood risks. A day is classified as a high tide flood day if a…

An ice body originating on land that covers an area of continental size, generally defined as covering >19,000 square miles (>50,000 km²) and that has formed over thousands of years through accumulation and compaction of snow. Presently, only two ice sheets exist: the Antarctic Ice Sheet and the…

The physical structures, services, and institutions (i.e., roads, electric utilities, legal systems) needed by a community, organization, or country.

The United Nations body for assessing the science related to climate change.

Water that is either removed from land (through groundwater pumping, for example) or impounded on land (through dam building, for example) and can cause a net change in the total water found in the ocean.

Refers to sea level estimates between the time period of 2050 to 2150, and beyond.

Used to denote a low level of agreement on how models represent key processes (e.g. partial, rapid ice sheet disintegration) and limited evidence supporting model outputs.

Water levels that exceed about 4ft (1.2m) above average high tide. These are often quite destructive, requiring post-event repairs and/or rebuilding and evacuations.

Mean higher high water is the average of the highest water level observed in each day over a period

Used to denote moderate agreement among experts on the model treatment of key processes (e.g. those used in the IPCC AR6 SSPs) and moderate lines of evidence supporting model outputs.

Water levels exceed about 2 ft (0.6 m) above average high tide. These floods are disruptive to communities (e.g., stormwater backups and road closures)

Water levels exceed about 3 ft (0.9 m) above average high tide. These floods tend to cause more damage than minor floods (e.g., to homes for businesses)

Used when a scientific assessment of multiple lines of evidence collectively and consistently points towards a single sea level scenario or range across multiple sea level scenarios.

Masses of ice found in mountainous regions that store vast amounts of freshwater. As these glaciers melt due to global warming, they contribute to sea level rise by adding additional water to the oceans.

Refers to sea level estimates between the time period between now and 2050.

Systematic collection and recording of data related to the Earth's climate system.

An ocean is a  vast body of saline water that covers approximately 71% of the Earth's surface and contains roughly 97% of the planet's water. Oceans are divided into five major basins: the Pacific, Atlantic, Indian, Southern, and Arctic Oceans. These large bodies of water are interconnected and play…

The plausible range of sea-level rise is the credible and reasonable range of future sea level rise supported by published, peer-reviewed publications and consensus documents where available.

The process where water vapor condenses in the atmosphere to form water droplets that fall to the Earth as rain, sleet, snow, hail, etc.

Refers to the short-term forecasting of climate conditions based on the current state of the climate system and its known patterns of variability. These predictions typically cover timescales from a few months to a few years and aim to forecast specific climate phenomena, such as seasonal weather…

A probabilistic method or model is based on the theory of probability or the fact that randomness plays a role in predicting future events. Probabilistic models incorporate random variables and probability distributions into the model of an event or phenomenon.

Involves the long-term simulation of future climate conditions based on various scenarios of greenhouse gas emissions and other socio-economic factors. These projections extend over decades to centuries and are not predictions of specific future weather events but rather scenarios of how the climate…

The speed or degree of change in a particular environmental parameter over a specified period.

Changes in sea level that may differ from the global average sea level change due to local factors such as subsidence, ocean currents, variations in land height, and whether the land is still rebounding from the compressive weight of Ice Age glaciers.

Scenarios used in climate modeling to describe different trajectories of greenhouse gas concentrations and their impact on global warming. Each RCP represents a different level of radiative forcing, which is the change in energy balance in the Earth’s atmosphere due to greenhouse gases.

As the sea-levels rise, the “salt front” (location of the freshwater-saltwater line) may progress further inland. This encroachment may be further exacerbated by drought, reduced rainfall or changes in water use and demand. Saltwater intrusion can result in the need for water utilities to increase…

An object that orbits around a larger body in space. Satellites can be natural, like moons orbiting planets, or artificial, meaning they are human-made objects. Artificial satellites are launched into space for various purposes, such as communication, weather monitoring, navigation, and scientific…

An instrument onboard a satellite that measures the distance between the satellite and the Earth's surface. It does this by sending radar pulses to the surface and timing how long they take to return. This data is used to determine sea surface heights and monitor ocean currents.

A plausible description of how sea level may change based on a coherent and internally consistent set of assumptions about key driving forces (e.g., emissions ) and relationships. Note that scenarios are neither predictions nor forecasts but are used to provide a view of the implications of…

Scenarios used by scientists to predict how global societies, economies, and environments might change over the 21st century. These pathways help researchers understand how different levels of social and economic development can affect climate change and how societies might respond to it. SSPs are…

A synthesis from the IPCC released in 2023 that provides an overview of the state of knowledge on the science of climate change, emphasizing new results since the previous report in 2014.

Sea level change caused by the combined effects of thermal expansion and salinity changes (steric effects) and changes in ocean circulation (dynamic effects). This term captures the influence of both temperature and salinity on seawater volume and the redistribution of water due to currents and…

The temporary increase, at a particular locality, in the height of the sea due to extreme meteorological conditions (low atmospheric pressure and/or strong winds). The storm surge is defined as being the excess above the level expected from the tidal variation alone at that time and place.

The downward movement of the Earth's surface. It can be caused by natural processes such as tectonic activity, sediment compaction, and the extraction of underground resources like water, oil, or gas.

An instrument fitted with sensors that continuously record the height of the surrounding water-level to help with tide and sea level change monitoring. Measures the height of the sea relative to land at a specific location.

Periodic rise and fall of sea levels caused by the gravitational interactions between the Earth, the Moon, and the Sun. The variations in tidal patterns and magnitudes are influenced by the relative positions of the Moon, the Sun, and the Earth, as well as by the topography of the coastline and the…

Estimates of relative sea level rise out to 2050. To create them, the rate and acceleration of sea level rise from 1970 to present is calculated from sea level rise observations from sets of tide gauges, and then extrapolated into the future. 

A long-term, persistent change in the average state of the climate system or its components, such as temperature, precipitation, or sea level. These trends are identified by analyzing climate data over extended periods, typically decades or longer, to distinguish systematic changes from short-term…

The upward movement of the Earth's surface. It can occur due to tectonic activity, such as the collision of tectonic plates, or as a result of glacial isostatic adjustment, where the land rebounds after being compressed by heavy ice sheets during the last Ice Age.

The upward or downward movement of the Earth's surface.. This movement can result from tectonic activity, glacial rebound, or human activities like groundwater withdrawal. It influences relative sea level change by either amplifying (subsidence) or mitigating (uplift) the effects of sea level rise.