synonymenvironmental change (A series of biophysical changes on land, ocean and atmosphere caused by the system driven by the interwoven human activities and natural processes) generally refers to global environmental changes
Global Environmental Change (GEC)human activityA series of biophysical changes in land, ocean and atmosphere caused by the system driving interwoven with natural processes.It can pose a great threat to mankind.[1]
From the increasingly serious problem of global environmental changeEarth systemA consortium that conducts the integrated study of the Earth System, aims to promote the integration research and change research of the earth system, and uses these changes to study the global sustainable development capability——Earth System Science Alliance(Earth System Science Partnership, ESSP) consists of the following four major global environmental change plans:
Spatial-temporal spectral characteristics of global environmental change
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As an open system, the interaction of solar radiation, atmospheric composition, atmospheric process, sea land relationship, ocean circulation, ice sheet, land topography, surface composition and human activities in the Earth's surface system can be shown as multi-level driving, response, feedback, amplification and other very complex relationships in a time series.
Therefore, global environmental change will show somePeriodic change, but also some gradual changes and abrupt changes.
time scale
Global environmental change can be divided into five temporal characteristics:
1. Millions to billions of years (geological history period)
Global change events are controlled by the evolution laws and processes of the Earth's planets, such asLithospheric plateThe movement of the Earth led to the vicissitudes of the earth's evolution. The mountain building and land building movements on the land formed mountains, plateaus and other large topographic units, the formation and evolution of the atmosphere and hydrosphere, and the origin of life and the emergence of primitive humans.(Irreversible events).
2. Thousands to hundreds of thousands of years (the latest geological historical period)
Quaternary glaciation-The alternation of interglacial periods, the rise and fall of the sea surface, and the changes of atmospheric composition accompanied by changes in temperature, dryness and wetness, such as the change of dust content, the development of ancient soil layers, the distribution, migration and extinction of biological species, and the birth and development of human civilization.(Reversible event)
3. Years to hundreds of years (inter year, inter decade to inter century)
Typical events include the trend rise of global temperature, quasi periodic fluctuations and mutations of temperature, sea surface temperature, precipitation, runoff, surface erosion, plant phenology and growth season, changes in plant population structure and possible movement of vegetation belt.
Driving forces: long-term changes in solar activity, volcanic activity, atmospheric circulation, El Nino Southern Oscillation and other natural factorsAtmospheric greenhouse effectThe enhancement of was the factor.
4. Days to quarters
Typical events: seasonal fluctuations of atmospheric circulation, seasonal fluctuations of temperature, precipitation and surface experience, seasonal changes of plant communities and farming seasons, soil plant atmosphereBiogeochemical cycleThe interannual change of.
Driving force: annual cycle of solar radiation input.
5. Seconds to hours:
Typical events: daily changes of climate elements, weather phenomena from several minutes to several hours, daily changes of plant and soil temperature, and material and energy transfer between soil plant atmosphere.
Driving force: daily cycle of solar radiation energy input.
Spatial scale
1. Global scale: the spatial range is more than 20000 km, which is about equivalent to the hemispherical to global scale.Characteristic events: solar radiation energy distribution, atmospheric circulation and ocean current, greenhouse effect and global climate change, ozone layer destruction, etc.(1a~billions a).
2. Regional scale: the spatial range is 100~20000 km, and the regional units include the natural zones and sea areas on the continent, ocean and land.The characteristic events are monsoon and large-scale weather process, ocean current, El Nino Southern Oscillation, tectonic movement and orogeny of rock surrounding plate, alternation of ice age and ice age, climate zone and zonal vegetation soil formation, etc.(1a~billions a).
3. Local scale: the spatial range is 10~100km.Characteristic event earthquake, water and soil loss in the basin, mesoscale weather system (such as mesocyclone, thunderstorm, etc.), horizontal change of plant phenology, urban climate and air pollution, pollution of rivers and waters, mineralization, etc.(1d~million a)
4. Local scale: spatial range<10km.Characteristic events include volcanic eruptions, surface erosion in small watersheds, small-scale weather systems (such as tornadoes, valley winds, sea and land winds), changes in plant phenology with topography, micrometeorology of vegetation canopy, nutrient cycling in soil, point source and line source pollution events, etc.(s~1a)
Relevance of space-time scales
The time scale and space scale of various events and processes in the global system are related.Generally speaking, events and processes with larger spatial scales have larger time scales;The time scale of events and processes with small spatial scale is also small.The spatial scale of global climate change can reach more than 20000 km, and the corresponding time scale is decades to hundreds of years, while the spatial scale of vegetation canopy micrometeorology change is only a few centimeters to meters, and the corresponding time scale is seconds to minutes.[1]
Driving forces of global environmental change
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External factors
Solar radiation;Solar activity: sunspots and flares, plaques, flares, prominences, etc.
Earth internal factors
(1) A series of changes caused by plate movement: changes in land and sea distribution, uplift of mountains and plateaus, volcanic activity (cooling → "parasol effect")
(2) The polar drift caused by the distribution of material inside the earth.
human factor
The changes in the state and function of the earth system caused by human activities have accelerated rapidly in the past 200 years since industrialization. On a time scale of tens to hundreds of years, the impact of human activities on global change and the impact of global change on human beings are extremely significant,Human ecosystemThe process has become an indispensable part of the global change process.
However, human ecosystem, land cover change, and pollutant emissions affect the global biogeochemical cycle process, the composition of the earth's surface system → the functional imbalance and change of the natural system, and lead to global environmental change through cumulative or systematic changes.(For example, the record of the highest temperature in the world is constantly broken)[1]
