Greenland ice sheetThe Greenland ice sheet (Grønlands indlandsis, Sermersuaq) is a vast body of ice covering , roughly near 80% of the surface of Greenland. It is sometimes referred to as an ice cap, or under the term inland ice, or its Danish equivalent, indlandsis. The acronym GIS is frequently used in the scientific literature. It is the second largest ice body in the world, after the Antarctic ice sheet. The ice sheet is almost long in a north–south direction, and its greatest width is at a latitude of 77°N, near its northern margin.
EvapotranspirationEvapotranspiration (ET) is the combined processes by which water moves from the earth's surface into the atmosphere. It covers both water evaporation (movement of water to the air directly from soil, canopies, and water bodies) and transpiration (evaporation that occurs through the stomata, or openings, in plant leaves). Evapotranspiration is an important part of the local water cycle and climate, and measurement of it plays a key role in agricultural irrigation and water resource management.
Ice coreAn ice core is a core sample that is typically removed from an ice sheet or a high mountain glacier. Since the ice forms from the incremental buildup of annual layers of snow, lower layers are older than upper ones, and an ice core contains ice formed over a range of years. Cores are drilled with hand augers (for shallow holes) or powered drills; they can reach depths of over two miles (3.2 km), and contain ice up to 800,000 years old. The physical properties of the ice and of material trapped in it can be used to reconstruct the climate over the age range of the core.
Glacier mass balanceCrucial to the survival of a glacier is its mass balance of which surface mass balance (SMB), the difference between accumulation and ablation (sublimation and melting). Climate change may cause variations in both temperature and snowfall, causing changes in the surface mass balance. Changes in mass balance control a glacier's long-term behavior and are the most sensitive climate indicators on a glacier. From 1980 to 2012 the mean cumulative mass loss of glaciers reporting mass balance to the World Glacier Monitoring Service is −16 m.
GreenlandGreenland (Kalaallit Nunaat, kalaːɬːit nʉnaːt; Grønland, ˈkʁɶnˌlænˀ) is a North American autonomous territory in the Kingdom of Denmark. It is one of three countries that form the Kingdom, the others being Denmark proper and the Faroe Islands; the citizens of all three countries are citizens of Denmark and the European Union. The capital and largest city of Greenland is Nuuk. Greenland lies between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago.
General circulation modelA general circulation model (GCM) is a type of climate model. It employs a mathematical model of the general circulation of a planetary atmosphere or ocean. It uses the Navier–Stokes equations on a rotating sphere with thermodynamic terms for various energy sources (radiation, latent heat). These equations are the basis for computer programs used to simulate the Earth's atmosphere or oceans. Atmospheric and oceanic GCMs (AGCM and OGCM) are key components along with sea ice and land-surface components.
Ice sheetIn glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at Last Glacial Maximum, the Laurentide Ice Sheet covered much of North America, the Weichselian ice sheet covered Northern Europe and the Patagonian Ice Sheet covered southern South America. Ice sheets are bigger than ice shelves or alpine glaciers.
Water vaporWater vapor, water vapour or aqueous vapor is the gaseous phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Water vapor is transparent, like most constituents of the atmosphere. Under typical atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation. It is less dense than most of the other constituents of air and triggers convection currents that can lead to clouds and fog.
Climate modelNumerical climate models use quantitative methods to simulate the interactions of the important drivers of climate, including atmosphere, oceans, land surface and ice. They are used for a variety of purposes from study of the dynamics of the climate system to projections of future climate. Climate models may also be qualitative (i.e. not numerical) models and also narratives, largely descriptive, of possible futures.
Global surface temperatureIn earth science, global surface temperature (GST; sometimes referred to as global mean surface temperature, GMST, or global average surface temperature) is calculated by averaging the temperature at the surface of the sea and air temperature over land. Periods of global cooling and global warming have alternated during Earth's history. of reliable global temperature measurements began in the 1850—1880 time frame. Through 1940, the average annual temperature increased, but was relatively stable between 1940 and 1975.
Antarctic ice sheetThe Antarctic ice sheet is one of the two polar ice caps of Earth. It covers about 98% of the Antarctic continent and is the largest single mass of ice on Earth, with an average thickness of over 2 kilometers. Separate to the Antarctic sea ice it covers an area of almost and contains of ice. A cubic kilometer of ice weighs approximately 0.92 metric gigatonnes, meaning that the ice sheet weighs about 24,380,000 gigatonnes. It holds approximately 61% of all fresh water on Earth, equivalent to about 58 meters of sea level rise if all the ice were above sea level.
Climate changeIn common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to Earth's climate. The current rise in global average temperature is more rapid than previous changes, and is primarily caused by humans burning fossil fuels. Fossil fuel use, deforestation, and some agricultural and industrial practices increase greenhouse gases, notably carbon dioxide and methane.
Ice-sheet modelIn climate modelling, Ice-sheet models use numerical methods to simulate the evolution, dynamics and thermodynamics of ice sheets, such as the Greenland ice sheet, the Antarctic ice sheet or the large ice sheets on the northern hemisphere during the last glacial period. They are used for a variety of purposes, from studies of the glaciation of Earth over glacial–interglacial cycles in the past to projections of ice-sheet decay under future global warming conditions. Beginning in the mid-18th Century, investigation into ice sheet behavior began.
Atmospheric temperatureAtmospheric temperature is a measure of temperature at different levels of the Earth's atmosphere. It is governed by many factors, including incoming solar radiation, humidity and altitude. When discussing surface air temperature, the annual atmospheric temperature range at any geographical location depends largely upon the type of biome, as measured by the Köppen climate classification Lapse rate Temperature varies greatly at different heights relative to Earth's surface and this variation in temperature characterizes the four layers that exist in the atmosphere.
Sea surface temperatureSea surface temperature (SST), or ocean surface temperature, is the ocean temperature close to the surface. The exact meaning of surface varies according to the measurement method used, but it is between and below the sea surface. Air masses in the Earth's atmosphere are highly modified by sea surface temperatures within a short distance of the shore. Localized areas of heavy snow can form in bands downwind of warm water bodies within an otherwise cold air mass.
Thermal massIn building design, thermal mass is a property of the mass of a building that enables it to store heat and provide inertia against temperature fluctuations. It is sometimes known as the thermal flywheel effect. The thermal mass of heavy structural elements can be designed to work alongside a construction's lighter thermal resistance components to create energy efficient buildings.
Instrumental temperature recordThe instrumental temperature record is a record of temperatures within Earth's climate based on direct, instrument-based measurements of air temperature and ocean temperature. Instrumental temperature records are distinguished from indirect reconstructions using climate proxy data such as from tree rings and ocean sediments. Instrument-based data are collected from thousands of meteorological stations, buoys and ships around the globe.
Effects of climate changeClimate change affects the physical environment, ecosystems and human societies. Changes in the climate system include an overall warming trend, more extreme weather and rising sea levels. These in turn impact nature and wildlife, as well as human settlements and societies. The effects of human-caused climate change are broad and far-reaching, especially if significant climate action is not taken. The projected and observed negative impacts of climate change are sometimes referred to as the climate crisis.
Scientific consensus on climate changeThere is a strong scientific consensus that the Earth is warming and that this warming is mainly caused by human activities. This consensus is supported by various studies of scientists' opinions and by position statements of scientific organizations, many of which explicitly agree with the Intergovernmental Panel on Climate Change (IPCC) synthesis reports. Nearly all actively publishing climate scientists say humans are causing climate change. Surveys of the scientific literature are another way to measure scientific consensus.
Attribution of recent climate changeEfforts to scientifically ascertain and attribute mechanisms responsible for recent global warming and related climate changes on Earth have found that the main driver is elevated levels of greenhouse gases produced by human activities, with natural forces adding variability. The likely range of human-induced surface-level air warming by 2010–2019 compared to levels in 1850–1900 is 0.8 °C to 1.3 °C, with a best estimate of 1.07 °C. This is close to the observed overall warming during that time of 0.9 °C to 1.
