Introduction — Outline of Earth Sciences
Earth science, often termed geoscience or the geosciences (and occasionally referenced as “Earthquake sciences”), comprises the collective scientific disciplines that investigate planet Earth. Situated within the physical sciences and the wider natural sciences, it employs empirical, physics-based and quantitative methods to observe, model and explain Earth’s systems. Earth’s unique status as the only known life-bearing planet motivates its treatment as a distinct domain within planetary science.
The field addresses the planet’s structure in an integrated way, explicitly incorporating the atmosphere alongside solid-Earth components and emphasizing interactions among lithosphere, hydrosphere, cryosphere and atmosphere. Conceptual schematics and hierarchical outlines are commonly used to represent these relationships and to organize the many subfields. This organizational framing highlights the inherently interdisciplinary character of Earth science: multiple branches converge to study coupled physical processes and to map thematic links across scales and domains.
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A planetary-scale false-color composite produced from September 1997 to August 2000 by the SeaWiFS Project (NASA/Goddard and ORBIMAGE) illustrates global patterns of oceanic and terrestrial photoautotroph abundance, providing a broad synoptic view of the biosphere and underscoring how remotely sensed datasets can represent interactions among Earth’s subsystems.
Earth’s ecosphere is commonly conceptualized as a set of nested, interacting spheres that approximate the planet’s form. Four principal spheres—atmosphere, biosphere, hydrosphere and geosphere—capture most subsystem interactions, while the ecosphere as a whole resides within the heliosphere. Beyond these, the magnetosphere constitutes the outermost region in which the planet’s magnetic field governs the motion of charged particles.
The atmosphere is the gaseous envelope surrounding Earth and is described both by vertical layers defined by temperature structure (troposphere, stratosphere, mesosphere, thermosphere, exosphere) with intervening boundaries (tropopause, stratopause, mesopause, thermopause, exobase), and by dynamical mixing regimes (the homosphere below the turbopause where gases are well mixed, and the heterosphere above where molecular diffusion produces compositional stratification). The lowest part of the troposphere directly influenced by surface friction and exchange processes is the planetary boundary layer. Superposed on these classifications, the ionosphere denotes the ionized component of the upper atmosphere—primarily within the mesosphere–thermosphere region—where solar radiation creates free electrons and ions.
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The biosphere comprises the totality of ecosystems and living organisms and their interactions. Anthropogenic modifications of the environment are often described collectively as the anthroposphere, while the rarely used term noosphere designates the sphere of human thought and cultural influence. The hydrosphere encompasses all liquid and vapor water on, under and above Earth’s surface; portions of the hydrosphere that are frozen (glaciers, ice sheets, sea ice, permafrost) comprise the cryosphere. The pedosphere—the soil envelope at Earth’s surface—acts as a dynamic interface linking lithosphere, atmosphere, hydrosphere and biosphere through weathering, biotic activity and soil-forming processes.
The geosphere or Solid Earth denotes Earth’s solid constituents and internal structure. Compositional layering defines the crust as the outer solid shell, the Moho as the crust–mantle boundary, and the mantle as the thick silicate region between crust and core. Mechanical and seismic divisions overlay this framework: the rigid lithosphere forms the mechanical outer shell, beneath which the asthenosphere is a mechanically weak, ductile portion of the upper mantle; deeper mantle zones (sometimes termed mesozone) lie above the core, and the Gutenberg discontinuity marks the seismic boundary between mantle and core. The core resulted from planetary differentiation that concentrated dense metallic elements centrally: the outer core is a liquid iron–nickel layer whose motions drive the geomagnetic field, the Lehmann discontinuity separates it from the solid inner core, which consists principally of an iron–nickel alloy.
Atmospheric science
Atmospheric science is an integrative field that treats the atmosphere as a dynamic component of the Earth system, examining its composition, physical and chemical processes, and exchanges of energy and mass with the hydrosphere, cryosphere, biosphere and lithosphere. It spans scales from molecular reactions and cloud microphysics to planetary-scale circulation and multi-decadal climate change, and underpins practical activities such as air-quality management, weather forecasting and climate projection.
Climatology frames climate as the statistical characterization of weather variables—temperature, precipitation, wind, humidity and pressure—averaged and analyzed over extended times and regions. Climatologists seek to quantify mean states, variability, trends, teleconnections and extremes using observational records, reanalyses and model ensembles, thereby situating contemporary changes within longer-term context and projecting future conditions.
Meteorology concentrates on atmospheric phenomena on short to medium time scales. It addresses synoptic systems (fronts, cyclones, anticyclones), mesoscale processes (convective systems, sea breezes, flow over topography) and boundary-layer dynamics, and relies on in situ measurements, remote sensing, numerical weather prediction and data assimilation to generate deterministic and probabilistic forecasts.
Paleoclimatology reconstructs past climates over geological to millennial timescales by interpreting natural archives—ice cores, tree rings, lake and marine sediments, speleothems and corals—to infer past temperature, precipitation, atmospheric composition and circulation. These reconstructions extend the observational record, test model sensitivity and feedbacks, and place recent climate variability in a long-term perspective. A specialized branch, paleotempestology, uses geological and documentary proxies (for example, coastal overwash deposits, coral growth anomalies and tree-ring scars) to reconstruct the frequency, intensity and spatial patterns of intense storms and tropical cyclones and their links to climate variability and sea-level change.
Atmospheric chemistry examines the composition of the air and the chemical pathways that regulate concentrations of key species—ozone, aerosols, reactive trace gases and greenhouse gases—through photochemistry, heterogeneous reactions on particle surfaces and gas–aerosol interactions. It traces sources, sinks, transport and transformation processes and evaluates implications for air quality, human health and radiative forcing. Complementing chemistry, atmospheric physics applies fluid dynamics, thermodynamics and radiative-transfer theory to explain circulation, wave dynamics, convection, turbulence, cloud microphysics and the planetary radiation balance, providing the quantitative foundations used to parameterize processes in weather and climate models.
Across these subdisciplines a common methodological toolkit is employed: field networks and radiosondes, satellite and radar remote sensing, laboratory analyses (isotopes, chemical tracers, particle characterization), paleoproxy sampling and chronologies, and numerical modeling that ranges from large-eddy simulations to global climate models. The synthesis of observations, laboratory work and models enables process attribution, quantitative prediction and the translation of scientific insight into applied and policy-relevant information.
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Geology
Geology is the integrated study of Earth’s materials, structures, physical properties and the processes that produce, modify and redistribute rocks, landforms and subsurface features through time. It combines descriptive and interpretive approaches to reconstruct Earth’s history, establish absolute and relative ages of rocks and sediments, and relate stratigraphic sequences to depositional environments and basin evolution.
The discipline encompasses mineral- and rock-focused sciences—mineralogy and gemology characterize mineral species and gem materials; petrology investigates the origin, composition and internal textures of igneous, metamorphic and sedimentary rocks; and mineral physics probes the mechanical and thermodynamic behaviour of materials at depth. Chemical and isotopic methods in geochemistry and geochronology provide compositional tracers and numerical age constraints that are central to understanding processes such as mineral formation, weathering and fluid–rock interaction.
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Surface and near-surface processes are treated through sedimentology, sedimentary stratigraphy and geomorphology, which link transport and depositional mechanisms (fluvial, eolian, coastal, mass-wasting) to landscape development and resource distribution. Complementary fields address cryospheric and volcanic phenomena: glaciology examines ice dynamics and their geomorphic imprint, while volcanology studies magma generation, eruption dynamics and degassing. Structural geology and tectonics interpret deformation features (folds, faults, fabrics) to elucidate kinematics and mechanics of mountain building, basin formation and seismic hazard.
Seismology applies quantitative wave physics to earthquakes and elastic-wave propagation, whereas paleoseismology documents prehistoric seismic events in stratigraphic and geomorphic records. Hydrologic aspects are covered by hydrogeology, which characterizes groundwater occurrence and flow in porous and fractured media, and by environmental geology, which applies geological knowledge to contamination, land-use planning, slope stability and remediation. Applied resource-oriented branches include economic geology, petroleum geology and engineering geology, each focused on exploration, evaluation and the integration of geological data with design and hazard mitigation.
Geology also extends beyond Earth: planetary geology applies terrestrial principles to other planetary bodies, and geodetic sciences quantify Earth’s shape, orientation and gravity field with implications for mass distribution and sea level. Geophysical methods (gravity, magnetics, seismic, electromagnetic, heat-flow) and geomagnetics provide the quantitative tools to image subsurface structure and to study the origin and temporal variability of the magnetic field. At the micro- and bio-geological interface, micropaleontology, paleontology and palynology (broadly construed to include particulate proxies) reconstruct past environments and biostratigraphy, while geomicrobiology investigates microbe–mineral interactions and microbially mediated geochemical cycles.
Geography is the systematic study of the Earth’s surface and the societies that occupy it, integrating natural processes, human activities and the spatial arrangements of places and regions. As a discipline it bridges the physical and the social: physical geography investigates environmental systems housed within the atmosphere, hydrosphere, biosphere and geosphere, while human geography examines the spatial organization of cultures, economies and political life.
Physical geography encompasses fields such as hydrology—which applies scientific and engineering principles to the distribution and movement of water relative to land—and the analysis of climate, landforms, soils, vegetation and interactions between surface and subsurface processes. Human geography addresses the spatial dimensions of human existence, including the production and meaning of cultural landscapes, patterns of population and economic activity, urban systems, territorial governance and the reciprocal influence between communities and their environments.
A suite of methods and technologies underpins contemporary geographic inquiry. Cartography and topography translate terrain and spatial relationships into map form, addressing symbolization, projection, scale, relief representation and elevation modelling. Geographic information science treats the theory and methods for collecting, modelling, visualizing and assessing the quality of spatial data within GIS platforms. Geostatistics provides the statistical tools to model spatial dependence, interpolate values across space and quantify uncertainty in spatial predictions. Remote sensing and photogrammetry acquire spatial information from airborne or satellite sensors and derive accurate three‑dimensional measurements from imagery, respectively. Global Navigation Satellite Systems and related satellite navigation services deliver precise positioning and timing essential for mapping, surveying and geolocation.
Spatial decision support systems combine spatial datasets, analytical models and scenario testing to inform land‑use, resource management and planning choices. Within the environmental domain, geographers engage with environmental chemistry and various soil sciences: environmental soil science examines human interactions with the pedosphere and its links to the biosphere, lithosphere, hydrosphere and atmosphere; edaphology focuses on soil influences on organisms and ecosystems; and pedology treats soils as natural bodies within the landscape. Together these subfields and methods enable geography to analyse and interpret the complex spatial patterns and processes that shape the Earth and its societies.
Oceanography
Oceanography is an interdisciplinary science that examines the ocean as an integrated component of the Earth system, emphasizing spatial and temporal patterns of ocean properties and the exchanges between ocean, atmosphere, cryosphere and continents. It addresses the ocean’s functions within global climate, biogeochemical cycles and marine ecosystems, and spans processes that operate from local coastal zones to basin-scale and global circulation.
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Physical oceanography investigates the ocean’s dynamic state: currents, tides, waves, stratification, mixing and the transport of heat and salt. It characterizes how these processes vary across scales and how large-scale circulation links oceanic behavior to weather and climate.
Chemical oceanography treats the composition and reactive behavior of seawater and dissolved constituents. Key concerns include salinity and major ion distributions, nutrient and trace element cycles, dissolved gases, acid–base and redox conditions, and the pathways by which chemicals are transformed, moved and stored in marine environments.
Biological oceanography explores how marine organisms both shape and respond to their physical, chemical and geological surroundings. Topics include primary production, food-web structure, the distribution and transport of plankton and benthos, and the biological control of nutrient and carbon cycling, as well as ecological responses to physical forcing such as mixing and circulation.
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Paleoceanography and marine geology extend oceanographic inquiry through time and into the sedimentary record. Paleoceanography reconstructs past ocean conditions—temperature, circulation, chemistry and sea level—using proxies preserved in sediments, microfossils and geochemical signatures. Marine geology examines the origin and evolution of the seafloor and continental margins, including plate tectonics, mid‑ocean ridge spreading, trench and volcanic formation, and sedimentation on shelves and abyssal plains, which together archive Earth history. Limnology, the study of inland waters, is treated alongside these marine disciplines as it applies comparable physical, chemical and biological frameworks to lakes, rivers and wetlands and situates freshwater systems within broader catchment and landscape contexts.
Planetary science
Planetary science is the interdisciplinary study of planets (including Earth), natural satellites, and planetary systems—particularly those within the Solar System—emphasizing the physical and chemical processes that govern their formation, evolution, and current states. It integrates observational data, laboratory analyses, and numerical models to explain surface and interior properties, atmospheric behavior, and system-scale interactions across a range of bodies and environments.
Planetary geology applies the methods and concepts of terrestrial geology to bodies that orbit stars. It examines rock types and compositions (lithology), surface morphology and landforms, structural features such as faults and folds, and the range of geologic processes (volcanism, impact cratering, tectonism, erosion) that shape planets, moons, and other orbiting objects.
Selenography is the Moon-focused subset of planetary mapping and description. It documents lunar topography, impact craters, maria, highlands and other morphological elements, producing the cartographic and descriptive framework used for comparative studies, chronology (e.g., crater counting), and mission planning.
Theoretical planetology (theoretical planetary physics/chemistry) models planetary interiors by adopting explicit assumptions about bulk composition and the physical state of constituent materials and then computing radial profiles of internal properties—such as temperature, pressure, density, phase boundaries, and rheology. These calculations underpin interpretations of thermal evolution, magnetic field generation, and convective or tectonic behavior.
History of Earth science
Earth science comprises the integrated set of physical sciences concerned with Earth’s form, composition, processes and systems across local to global scales. It treats the planet as a coupled system in which atmosphere, hydrosphere, biosphere, lithosphere and pedosphere interact; disciplines within the field examine materials, dynamics and feedbacks that structure environments and transform them through time.
Atmospheric sciences form an umbrella for investigations of the air envelope, from short‑term weather dynamics to long‑term climate behavior. Meteorology applies atmospheric physics and dynamics to explain and forecast weather, atmospheric chemistry addresses the composition and reactive processes of gases and aerosols (with consequences for air quality, ozone and radiative forcing), climatology quantifies statistical properties and variability of climate, and paleoclimatology reconstructs past climates from proxy records to contextualize modern change.
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Hydrological and marine sciences treat water in its many settings. Hydrology studies the movement, distribution and quality of surface and subsurface waters, while hydrogeology focuses on groundwater flow, aquifer properties and human impacts on subsurface resources. Oceanography integrates physical, chemical, biological and geological perspectives on the sea; marine biology and freshwater biology (limnology) examine the organisms and ecological processes in marine and inland waters respectively. Coastal geography links these marine and terrestrial realms, combining geomorphology, oceanography and human dimensions to understand shoreline change and littoral use.
The solid Earth and surface processes are addressed by geology and its allied specialties. Geology, petrology and mineralogy investigate rocks and minerals, their origins and internal structures; geophysics uses seismic, gravitational, magnetic and electromagnetic methods to image interior structure and dynamics; seismology and volcanology focus on earthquakes and magmatic activity respectively. Geomorphology analyzes the agents that sculpt terrain—fluvial, glacial, aeolian, coastal and tectonic processes—while glaciology examines ice as an active landscape agent. Topography documents surface relief and form across land and planetary bodies.
Soil and near‑surface studies bridge the lithosphere and biosphere. Soil science characterizes formation, classification and properties of soils; environmental soil science emphasizes human–soil interactions, contamination, fertility and links with other Earth reservoirs. Environmental geology applies geological knowledge to problems such as erosion, land stability and subsurface contamination, often in close relation with hydrogeology.
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The biological and ecological dimensions of Earth science consider organisms and their spatial and temporal distributions. Ecology addresses interactions that determine abundance and community structure; biogeography links those patterns to environmental and geological history; population dynamics, parasitology and paleontology examine demographic processes, host–parasite relationships and the fossil record, respectively, connecting biological change to environmental and geological drivers.
Environmental science and environmental chemistry provide the integrative, quantitative frameworks for assessing anthropogenic impacts and ecosystem chemistry. These disciplines draw on physics, chemistry, biology, geology and social sciences to analyze pollutant fate, nutrient cycles and toxicological effects, informing management and mitigation of environmental problems.
Spatial and computational methods underpin measurement, representation and analysis. Geography synthesizes spatial analysis of places, regions and human–environment interactions; cartography translates spatial data into maps and globes; geodesy establishes the Earth’s size, shape, orientation and gravity field as the reference for positioning; geoinformatics and geostatistics supply the hardware, software, data standards and statistical tools for capturing, managing, modelling and visualizing geospatial data.
Comparative and planetary perspectives extend Earth science beyond our planet. Planetary geology applies terrestrial geological principles to planets, moons, asteroids and comets to interpret surfaces, interiors and impact histories, enabling cross‑planetary comparisons that illuminate Earth’s own evolution.
Together, these interlinked disciplines form a multidisciplinary framework for describing, explaining and managing Earth’s physical environments, from instantaneous weather events to billion‑year tectonic and biological transformations.
Earth science journals
Earth science journals publish research that spans the full breadth of spatial and temporal scales relevant to the Earth system, from localized landforms under a kilometre to planetary dimensions (Earth mean diameter ~12,742 km; mean radius ~6,371 km), and from instantaneous geophysical events (seconds–days) to processes unfolding over millions to billions of years. A principal theme is how phenomena operating at different scales interact to generate the geographic patterns observed in the lithosphere, hydrosphere, atmosphere, cryosphere and biosphere.
The disciplinary scope combines core subfields of physical geography and geoscience—plate tectonics and orogeny, volcanism and geodynamics, sedimentology and stratigraphy, geomorphology, glaciology and cryosphere dynamics, hydrology and oceanography, atmospheric processes and climate change, paleoenvironmental and paleoclimate reconstruction, and planetary geology. Work in these areas emphasizes cross‑cutting linkages among Earth’s spheres and integrates biological and chemical perspectives where relevant.
In Quaternary and Holocene studies, radiocarbon (14C) remains a central chronometer: the conventional 14C half‑life is ~5,730 years and practical dating extends to on the order of 50,000 years. Published studies routinely discuss calibration of 14C ages, reservoir offsets, and the combination of radiocarbon with complementary techniques (e.g., luminescence, U‑series) to build robust chronologies for coastal, lacustrine, peatland and archaeological records.
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Contemporary observational approaches reported in journals range from satellite remote sensing (optical and radar) to ground‑based networks. Interferometric Synthetic Aperture Radar (InSAR) affords millimetre‑to‑centimetre detection of surface deformation, Global Navigation Satellite Systems (GNSS) deliver millimetre–centimetre positional precision for crustal motion, seismic arrays enable tomographic imaging of subsurface structure, gravity and magnetic surveys map density and lithology contrasts, and airborne LiDAR yields high‑resolution topography crucial for quantifying geomorphic processes.
High‑value contributions are often synthetic reviews that critically integrate primary studies across regions and methods, develop conceptual frameworks for complex phenomena (for example, sea‑level change, sediment routing systems, or teleconnections in regional climate), distill robust patterns and remaining uncertainties, and articulate research priorities that bridge regional case studies and global comparisons.
Quantitative process studies and modeling provide the mechanistic backbone for interpretation and prediction. Examples include seismic‑wave propagation and tomography to resolve crust and mantle structure, geodetic constraints on strain accumulation and release for earthquake hazard assessment, numerical ice‑sheet models to estimate sea‑level contributions, coupled climate–carbon‑cycle simulations for past and future states, and data–model fusion approaches that convert diverse observations into testable process understanding.
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Applied research connects these foundations to societal needs: assessments of seismic and volcanic hazard, evaluations of coastal vulnerability to erosion and sea‑level rise, groundwater and hydrocarbon resource mapping, analyses of landscape response to tectonic and climatic forcing, and use of paleoenvironmental archives to inform resilience and adaptation strategies.
Finally, the field is inherently interdisciplinary and globally distributed. Research synthesizes geology, geophysics, chemistry, biology and remote sensing to produce geographically explicit insights across high‑latitude glaciers and polar systems, tropical monsoon domains, mountain belts, continental margins and island arcs. Comparative studies that include other planetary bodies further contextualize Earth’s geographic evolution within a planetary framework.
People influential in Earth science
A small number of practitioners and scholars have decisively shaped how Earth scientists and geographers conceptualize surface processes, deep time, planetary evolution and the socio‑political dimensions of environmental knowledge. Their work spans empirical field observation, theoretical synthesis, quantitative reconstruction and the mapping of science itself, and it underpins contemporary approaches to landscape interpretation, paleoenvironments, resource distribution and climate policy.
James Hutton established the methodological and temporal foundations of modern physical geography and geomorphology by arguing that present processes operating over immense timescales explain the rock record. Through field demonstrations—most famously angular unconformities at Siccar Point—he articulated cyclic erosion, sedimentation and uplift that form the rock cycle and introduced uniformitarian reasoning and “deep time” as essential frameworks for stratigraphic interpretation and landscape evolution.
Alfred Wegener reconceptualized past land distributions and paleoenvironments by proposing continental drift and the existence of Pangaea. He marshalled the geographic fit of continental margins, concordant orogenic belts, matching fossil assemblages across now-distant continents and aligned paleoclimatic indicators (e.g., glacial deposits in tropical latitudes) to argue for former continental juxtapositions. Although lacking a physical mechanism in his lifetime, Wegener’s biogeographic and paleoclimatic synthesis presaged and was later incorporated into the plate‑tectonic paradigm that mechanistically explains seafloor spreading, subduction and the mobility of lithospheric plates.
Contemporary researchers working at the interface of human and physical geography—represented here by the profile of Isabelle Daniel—combine spatial analysis, remote sensing and GIS with regional case studies to link local landscape dynamics to broader patterns of climate variability, resource distribution and socio‑environmental vulnerability. This integrative, scale‑bridging approach supports process‑based explanation, spatially explicit quantification of change (river basins, coasts, urban‑periurban gradients) and policy‑relevant regional assessment.
Robert Hazen’s concept of mineral evolution reframes mineralogy within planetary history by tracing how mineral diversity and complexity increase as a function of geodynamic, geochemical and biological change. Events such as the Great Oxidation Event generated novel mineral assemblages (e.g., iron oxides), providing a temporal and spatial template that links tectonics, surface environments and biosphere expansion; the concept also enables comparative studies of mineral inventories on other planetary bodies, informing planetary geography and astrobiological assessments of habitability.
Naomi Oreskes’ historical and bibliographic work maps the geography of scientific knowledge production and its intersections with politics and public policy. Her analyses—most notably the demonstration of broad consensus in peer‑reviewed climate literature and exposés of organized denial—situate climate science within institutional networks of scientists, funders, think tanks and media, elucidating how these networks shape regional and global policy responses and the transmission of scientific consensus across scales.
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Michael E. Mann has advanced quantitative paleoclimatology by synthesizing multiple proxy records (tree rings, ice cores, corals, sediments) into spatially resolvable reconstructions of past temperature variability. His work, including the well‑known “hockey stick” reconstruction, links proxy and instrumental records to demonstrate the exceptional nature of recent warming, underpins attribution of anthropogenic forcing, and informs geographic analyses of regional climate impacts, vulnerability mapping and adaptation planning.
Collectively, these figures illustrate the progression from place‑based field observation and conceptual models to spatially explicit, multi‑proxy and socio‑institutional analyses that span temporal scales from deep Earth history to contemporary anthropogenic change and spatial scales from local landscapes to the global system.