Earth sciences generally recognize the following four spheres as components of the systems that make up the entire natural environment:[8]​.

• - the lithosphere.

• - the hydrosphere.

• - the atmosphere.

• - the biosphere.

These spheres correspond to the set of rocks, waters, atmosphere and life, respectively.

Some scientists include, as part of the Earth's spheres, the cryosphere (corresponding to ice) as a distinct portion of the hydrosphere, as well as the pedosphere (corresponding to soil) as an active and intermingled sphere of the previous four.

Earth sciences (also known as geosciences or geological sciences) encompass all sciences related to the direct study of planet Earth as such. There are different disciplines in earth sciences, such as physical geography, geology, paleontology, geophysics, climatology, oceanography or geodesy, among others. These disciplines use physics, chemistry, biology, geochronology, and mathematics to develop a qualitative and quantitative understanding of the major areas or spheres of the Earth.

The Earth's crust ("Crust (geology)"), or lithosphere, is the outermost solid surface of the planet and is chemically and mechanically different from the underlying mantle. It is the rock layer of the Earth with which life and humans interact. It has been largely generated by igneous processes in which magma cools and solidifies to form solid rock. Below the lithosphere is the mantle that is heated by the decay of radioactive elements. The mantle, although solid, is in a state of rheological convection. This convection process causes the lithospheric plates to move, albeit slowly. The resulting process is known as plate tectonics. Volcanoes result primarily from the melting of subducted crustal or rising mantle material in mid-oceanic ridges and mantle plumes.

Contenido

La mayor parte del agua se encuentra en uno u otro tipo de cuerpo de agua natural.

Oceans

An ocean is a major body of saline water and a component of the hydrosphere. About 71% of the Earth's surface (an area of ​​about 362 million square kilometers) is covered by the ocean, a continuous body of water that is usually divided into several major oceans and smaller seas. More than half of this area is more than 3,000 meters (9,800 feet) deep. The average ocean salinity is about 35 ppt (parts per thousand) (3.5%), and almost all seawater has a salinity in the range of 30 to 38 ppt. Although generally recognized as several "separate" oceans, these waters comprise a global, interconnected body of salt water often known as the world ocean or the global ocean.[9]​[10]​ The deep seabed makes up more than half of the Earth's surface, and is among the least modified natural environments. The major oceanic divisions are defined in part by continents, various archipelagos, and other criteria: these divisions are (in descending order of size) the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Antarctic Ocean, and the Arctic Ocean.

Rivers

A river is a natural watercourse,[11]​ usually freshwater, that flows into an ocean, lake, sea or other river. A few rivers simply flow into the ground and dry up completely before reaching another body of water.

The water in a river is generally in a channel, formed by a stream bed between the banks "Bank (geography)"). In larger rivers there is also a wider floodplain formed by waters that cover the channel. Floodplains can be very wide relative to the size of the river channel. Rivers are part of the hydrological cycle. Water within a river is typically collected from precipitation (Precipitation (meteorology)), through surface runoff, groundwater recharge), springs, and the release of water stored in glaciers and snowpacks.

Small rivers may also be called by other names, such as stream. Its current is confined within a channel and a bank "Bank (geography)"). Currents play an important corridor role in connecting fragmented habitats and therefore in conserving biodiversity. The study of streams and watercourses in general is known as surface hydrology.[12]​.

Lakes

A lake (from Latin lacus) is a terrain feature, a body of water that is located at the bottom of the basin "Depression (geography)"). A body of water is considered a lake when it is inland, not part of an ocean, and is larger and deeper than a pond.[13]​[14]​.

Earth's natural lakes are generally found in mountainous areas, rift zones, and areas with recent or ongoing glaciations. Other lakes are found in endorheic basins or along the courses of mature rivers. In some parts of the world, there are many lakes due to the chaotic drainage patterns left over from the last Ice Age. All lakes are temporary on geologic time scales, as they will slowly fill with sediment or spill out. of the basin that contains them.

A pond is a body of standing water, whether natural or man-made, that is generally smaller than a lake. A wide variety of man-made bodies of water are classified as ponds, including water gardens designed for aesthetic ornamentation, fish ponds designed for commercial fish farming, and solar ponds designed to store thermal energy. Ponds and lakes are distinguished from streams by their current velocity. While currents in streams are easily observable, ponds and lakes possess thermal micro-currents and wind-moderated currents. These features distinguish a pond from many other aquatic terrain features, such as stream pools and tide pools.

Human impact on water

Humans impact water in different ways, such as modifying rivers (through dams and stream channeling), urbanization, and deforestation. These affect lake levels, groundwater conditions, water pollution, thermal pollution and marine pollution. Humans modify rivers using direct manipulation of channels.[15] They are building dams and reservoirs and manipulating the direction of rivers and the path of water. Dams are good for humans: some communities need reservoirs to survive. However, reservoirs and dams can negatively affect the environment and wildlife. Dams stop the migration of fish and the movement of organisms downstream. Urbanization affects the environment due to deforestation and change in lake levels, groundwater conditions, etc. Deforestation and urbanization go hand in hand. Deforestation can cause flooding, decreased stream flow, and changes in riverside vegetation. The change in vegetation occurs because when trees cannot obtain adequate water, they begin to deteriorate, leading to a decreased food supply for wildlife in an area.[15]​.

La atmósfera de la Tierra sirve como un factor clave para sostener el ecosistema planetario. La delgada capa de gases que envuelve a la Tierra se mantiene en su lugar por la gravedad del planeta. El aire seco consta de 78 % de nitrógeno, 21 % de oxígeno, 1 % de argón y otros gases inertes, como el dióxido de carbono. Los gases restantes a menudo se denominan gases traza,[17]​ entre los cuales se encuentran los gases de efecto invernadero, como el vapor de agua, el dióxido de carbono, el metano, el óxido nitroso y el ozono. El aire filtrado incluye trazas de muchos otros compuestos químicos. El aire también contiene una cantidad variable de vapor de agua y suspensiones "Suspensión (química)") de gotitas de agua y cristales de hielo vistos como nubes. Muchas sustancias naturales pueden estar presentes en pequeñas cantidades en una muestra de aire sin filtrar, incluyendo polvo, polen y esporas, rocío marino"), cenizas volcánicas y meteoroides. Varios contaminantes industriales también pueden estar presentes, tales como cloro (primario o en compuestos), compuestos de flúor, mercurio "Mercurio (elemento)") y azufre tales como dióxido de azufre (SO).

La capa de ozono de la atmósfera de la Tierra juega un papel importante en el agotamiento de la cantidad de radiación ultravioleta (UV) que llega a la superficie. Como el ADN se daña fácilmente con la luz UV, esto sirve para proteger la vida en la superficie. La atmósfera también retiene el calor durante la noche, lo que reduce las temperaturas diarias extremas.

Layers of the atmosphere

Earth's atmosphere can be divided into five main layers. These layers are determined primarily by whether temperature increases or decreases with altitude. From largest to smallest, these layers are:.

• - Exosphere: the outermost layer of the Earth's atmosphere extends from the exobase upwards, composed mainly of hydrogen and helium.

• - Thermosphere: the upper part of the thermosphere is the lower part of the exosphere, called the exobase. Its height varies with solar activity and ranges between 350-800 km (220-500 mi; ft). The International Space Station orbits in this layer, between 320 and 380 km (200 and 240 mi).

• - Mesosphere: The mesosphere extends from the stratopause to 80-85 km (50-53 mi; feet). It is the layer where most meteors burn up upon entering the atmosphere.

• - Stratosphere: The stratosphere extends from the tropopause to approximately 51 km (32 mi; ft). The stratopause, which is the boundary between the stratosphere and mesosphere, is usually 50 to 55 km (31 to 34 mi; ft).

• - Troposphere: The troposphere begins at the surface and extends to between 7 kilometers (22,965.9 feet) at the poles and 17 kilometers (55,774.3 feet) at the equator, with some variation due to climate. The troposphere is heated primarily by energy transfer from the surface, so on average the lower part of the troposphere is warmer and the temperature decreases with altitude. The tropopause is the boundary between the troposphere and the stratosphere.

Within the five main layers determined by temperature there are several layers determined by other properties.

• - The ozone layer is contained within the stratosphere. It is located mainly in the lower part of the stratosphere at approximately 15-35 km (9.3-21.7 mi; ), although the thickness varies seasonally and geographically. About 90% of the ozone in our atmosphere is contained in the stratosphere.

• - The ionosphere, the part of the atmosphere that is ionized by solar radiation, extends from 50 to 1000 km (31 to 621 mi; ) and generally overlaps both the exosphere and the thermosphere. It forms the inner edge of the magnetosphere.

• - The homosphere and the heterosphere: The homosphere includes the troposphere, the stratosphere and the mesosphere. The upper part of the heterosphere is composed almost entirely of hydrogen, the lightest element.

• - The planetary boundary layer is the part of the troposphere that is closest to the Earth's surface and is directly affected by it, mainly through turbulent diffusion.

The dangers of global warming are increasingly being studied by a large global consortium of scientists. These scientists are increasingly concerned about the possible long-term effects of global warming on our natural environment and the planet. Of particular concern are climate change and global warming caused by anthropogenic or man-made emissions of greenhouse gases, primarily carbon dioxide, which can act interactively and have adverse effects on the planet, its natural environment and the existence of human beings. It is clear that the planet is warming, and warming quickly. This is due to the greenhouse effect, caused by greenhouse gases, which trap heat within the Earth's atmosphere due to their more complex molecular structure that allows them to vibrate and, in turn, trap heat and release it back to the Earth.[18]​ This warming is also responsible for the extinction of natural habitats, which in turn leads to a reduction in wildlife populations. The most recent report from the Intergovernmental Panel on Climate Change (the group of the world's leading climate scientists) concluded that the earth will warm between 2.7 and almost 11 degrees Fahrenheit (1.5 to 6 °C) between 1990 and 2100.[19] Efforts have increasingly focused on mitigating the greenhouse gases that are causing climate change, developing adaptive strategies to global warming, and help humans, other animal and plant species, ecosystems, regions and nations adapt to the effects of global warming. Some examples of recent collaboration to address climate change and global warming include:.

• - The United Nations Framework Convention Treaty and the Convention on Climate Change, to stabilize greenhouse gas concentrations in the atmosphere at a level that prevents dangerous anthropogenic interference in the climate system.[20]​.

• - The Kyoto Protocol, which is the treaty protocol of the International Framework Convention on Climate Change, again with the goal of reducing greenhouse gases in an effort to prevent anthropogenic climate change.[21]​.

• - The Western Climate Initiative"), to identify, evaluate and implement collective and cooperative ways to reduce greenhouse gases in the region, focusing on a market-based cap-and-trade system.[22]​.

A significantly profound challenge is to identify natural environmental dynamics in contrast to environmental changes that are not within natural variations. A common solution is to adapt a static view that leaves out natural variations. Methodologically, this view could be defended when slowly changing processes and short time series are observed, while the problem arises when fast processes become essential in the object of study.

Climate

Climate analyzes the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle counts, and other weather elements in a given region over long periods of time. Weather, on the other hand, is the current condition of these same elements for periods of up to two weeks.

Climates can be classified according to the average and typical ranges of different variables, usually temperature and precipitation. The most widely used classification scheme is the one originally developed by Wladimir Köppen. The Thornthwaite system,[23]​ in use since 1948, uses evapotranspiration, as well as information on temperature and precipitation to study the diversity of animal species and the possible impacts of climate changes.[24]​.

weather

Weather is a set of all phenomena that occur in a given atmospheric area at a given time.[25]​ Most weather phenomena occur in the troposphere,[26][27]​ just below the stratosphere. Climate generally refers to daily temperature and precipitation activity, while climate is the term for average atmospheric conditions over longer periods of time.[28] When used without qualification, "climate" means the Earth's climate.

Climate occurs due to differences in density (temperature and humidity) between one place and another. These differences can occur due to the angle of the sun at any particular location, which varies depending on latitude from the tropics. The strong temperature contrast between polar and tropical air gives rise to the jet stream. Mid-latitude weather systems"), such as extratropical cyclones, are caused by the instability of the jet flow. Because the Earth's axis is tilted with respect to its orbital plane, sunlight hits it at different angles at different times of the year. At the Earth's surface, temperatures typically range between ±40 °C (100 °F to −40 °F) annually. For thousands of years, changes in the Earth's orbit have affected the amount and distribution of solar energy received by the Earth and influence the long-term climate.

Temperature differences at the surface in turn cause pressure differences. Higher altitudes are colder than lower altitudes due to differences in compressional heating. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and location. The atmosphere is a chaotic system, and small changes in one part of the system can grow to have large effects on the system as a whole. Human attempts to control the climate have occurred throughout human history, and there is evidence that civilized human activity, such as agriculture and industry, has inadvertently modified weather patterns.

Evidence suggests that life on Earth has existed for about 3.7 billion years.[29] All known life forms share fundamental molecular mechanisms, and based on these observations, theories of the origin of life attempt to find a mechanism that explains the formation of a single-celled primordial organism, from which all life originates. There are many different hypotheses regarding the route that could have been taken from simple organic molecules through precellular life to protocells and metabolism.

Although there is no universal agreement on the definition of life, scientists generally accept that the biological manifestation of life is characterized by organization, metabolism, growth, adaptation, response to stimuli, and reproduction.[30] It can also be said that life is simply the characteristic state of organisms. In biology, the science of living organisms, "life" is the condition that distinguishes active organisms from inorganic matter, including the capacity for growth, functional activity, and the continuous change that precedes death.[31][32]​.

A diverse variety of living organisms (life forms) can be found in the biosphere on Earth, and the common properties of these organisms (plants, animals, fungi, protists, archaea, and bacteria) are a carbon- and water-based cellular form, with complex organization and heritable genetic information. Living organisms have a metabolism, maintain homeostasis, have the capacity to grow, respond to stimuli, reproduce and, through natural selection, adapt to their environment in successive generations. The most complex living organisms can communicate through various means.

An ecosystem (sometimes used with the same meaning as environment) is a natural unit consisting of all plants, animals and microorganisms (biotic factors) in an area that function together with all non-living physical (abiotic) factors of the environment.[33]​.

Fundamental to the concept of ecosystem is the idea that living organisms are continually engaged in a set of highly interrelated relationships with all the other elements that constitute the biophysical environment in which they exist. Eugene Odum, one of the founders of the science of ecology, stated:

Any unit that includes all organisms (i.e., the "community") in a given area that interacts with the physical environment so that a flow of energy clearly leads to defined trophic structure, biotic diversity, and material cycles (i.e., the exchange of materials between living and non-living parts) within the system is an ecosystem.[34]​.

The concept of the human ecosystem is then based on the deconstruction of the human/nature dichotomy, and the emerging premise that all species are ecologically integrated with each other, as well as with the abiotic constituents of their biotope.

A greater number or variety of species or the biodiversity of an ecosystem can contribute to a greater capacity for ecosystem recovery, because there are more species present in a place to respond to change and, therefore, "absorb" or reduce its effects. This reduces the effect before the ecosystem structure is fundamentally changed to a different state. This is not universally the case and there is no proven relationship between the species diversity of an ecosystem and its ability to provide goods and services at a sustainable level.

The term ecosystem can also refer to man-made environments, such as human ecosystems and human-influenced ecosystems, and can describe any situation in which there is a relationship between living organisms and their environment. Today, there are fewer areas on the earth's surface free of human contact, although some natural or wild areas continue to exist without any form of human intervention.

Biomes are terminologically similar to the concept of ecosystems, and are climatically defined geographically defined areas of ecologically similar climatic conditions on Earth, such as communities of plants, animals, and soil organisms, often referred to as ecosystems. Biomes are defined based on factors such as plant structures (such as trees, shrubs and grasses), leaf types (such as leaf width and different parts), plant spacing (in forests, savannahs) and climate. Unlike ecozones, biomes are not defined by genetic, taxonomic, or historical similarities. Biomes are often identified with particular patterns of ecological succession and culminating vegetation.

Global biogeochemical cycles are critical for life, especially those of water, oxygen, carbon, nitrogen and phosphorus.[35]​.

• - The nitrogen cycle is the transformation of nitrogen and nitrogen-containing compounds in nature. It is a cycle that includes gaseous components.

• - The water cycle is the continuous movement of water on, above and below the Earth's surface. Water can change states between liquid, vapor, and ice at various places in the water cycle. Although the balance of water on Earth remains fairly constant over time, individual water molecules can come and go.

• - The carbon cycle is the biogeochemical cycle by which carbon is exchanged between the biosphere, pedosphere, geosphere, hydrosphere and atmosphere of the Earth.

• - The oxygen cycle is the movement of oxygen within and between its three main reservoirs: the atmosphere, the biosphere and the lithosphere. The main determining factor of the oxygen cycle is photosynthesis, responsible for the atmospheric composition and life of the modern Earth.

• - The phosphorus cycle is the movement of phosphorus through the lithosphere, hydrosphere and biosphere. The atmosphere does not play a major role in phosphorus movements, because phosphorus compounds are generally solid in the typical temperature and pressure ranges found on Earth.

Wilderness is generally defined as a natural environment on Earth that has not been significantly modified by human activity. The WILD Foundation goes into more detail, defining wildlife as:.

Protected wilderness areas and parks are considered important for the survival of certain species, ecological studies, conservation, solitude and recreation. The desert is deeply valued for cultural, spiritual, moral and aesthetic reasons. Some nature writers believe that wilderness areas are vital to the human spirit and creativity.[37]​.

The word "savage" derives from the notion of savagery; in other words, what is not controllable by humans. The etymology of the word wild comes from the Old English wildeornes, which in turn is derived from wildeor, meaning wild 'beast' (wild = 'wild' + deor = 'beast, deer').[38]​ From this point of view, it is the wild nature of a place that makes it a wilderness. The mere presence or activity of people does not disqualify an area from being "desert." Many ecosystems that are, or have been, inhabited or influenced by the activities of people can still be considered “wild.” This way of viewing the desert includes areas within which natural processes operate without much noticeable human interference.

Wildlife includes all non-domesticated plants, animals and other organisms. The domestication of wild plant and animal species for human benefit has occurred many times across the planet and has a large impact on the environment, both positive and negative. Wildlife can be found in all ecosystems. Deserts, rainforests, plains and other areas, including more developed urban sites, have distinct forms of wildlife. While the term in popular culture usually refers to animals that are not affected by civilized human factors, most scientists agree that wildlife around the world is (now) affected by human activities.

It is the common understanding of the "natural environment" that underlies environmentalism: a broad political, social and philosophical movement that advocates various actions and policies in order to protect what nature remains in the natural environment, or restore or expand the role of nature in this environment. While true wilderness is increasingly rare, wild nature (e.g., unmanaged forests, uncultivated grasslands, wildlife, wildflowers) can be found in many places previously inhabited by humans.

Goals for the benefit of people and natural systems, commonly expressed by environmental scientists and environmentalists, include:

• - Elimination of pollution and toxics in air, water, soil, buildings, manufactured products and food.

• - Preservation of biodiversity and protection of endangered species.

• - Conservation and sustainable use of resources such as water,[41] land, air, energy, raw materials and natural resources.

• - Stop human-induced global warming, which represents pollution, a threat to biodiversity and a threat to human populations.

• - Switching from fossil fuels to renewable energy in electricity, heating and cooling, and transportation, addressing pollution, global warming, and sustainability. This may include public transportation and distributed generation, which have benefits for traffic congestion and electrical reliability.

• - Shifting from meat-intensive diets to largely plant-based diets to help mitigate biodiversity loss and climate change.[42]​.

• - Establishment of nature reserves for recreational purposes and preservation of ecosystems.

• - Sustainable and cleaner waste management, including waste reduction (or even zero waste), reuse, recycling, composting, waste-to-energy and anaerobic digestion of sewage sludge.

• - Slowing and stabilization of human population growth.[43]​.

En algunas culturas, el término entorno carece de significado porque no hay separación entre las personas y lo que ellos ven como el mundo natural o su entorno.[44]​ Específicamente en los Estados Unidos, muchas culturas nativas no reconocen el «ambiente», o se ven a sí mismas como ambientalistas.[45]​.

Environment and indigenous peoples

Indigenous peoples are local communities that inhabit 22% of the planet's territory and have a population of between 350 and 500 million people around the world.[46] These populations were historically established in various territories throughout the planet, in which they adapted and created a close relationship between the individual and the inhabited ecosystem. In this adaptation process, indigenous peoples were modifying and creating an entire symbolic world between the environment and people, to the point of becoming or recognizing themselves as part of the natural ecosystem they inhabit; This statement is supported by oral stories transmitted through generations, which subsequently derived and contributed to the development of their identity processes;[47]​ This is why there are indigenous communities that recognize themselves as descendants of beings, animals and any other element of nature.

Currently, the super population and the increase in demands on natural resources have pushed large raw material extraction companies to search, negotiate and exploit new territories in the search for fertile lands suitable to continue generating resources for large industries worldwide.[48] This situation has led to the confrontation of the ways of understanding and seeing the world by Western peoples and indigenous and local peoples, which has generated asymmetrical interethnic relations with long-term repercussions for the groups involved.

Given the relationship between indigenous peoples and the environment, these human groups are recognized as the guardians of natural ecosystems, since they consider it part of their culture and the conducive home for the continuity of their cultural practices and customs.[49]​ This is why any attack on the natural system and indigenous territories directly threatens life and the continuity of indigenous ways of life.

Climate change and indigenous peoples

Indigenous peoples, as a result of their close connection with their territories, are being impacted and affected by the changes that are occurring in the climate and the increase in temperatures worldwide, either through periods of rain above normal and the worsening of drought in arid areas. The appearance of new viruses and the extinction of local fauna species.[50]​ Situation that directly attacks their economic systems and generates an exodus and mobilization of indigenous groups to urban areas.[50]​ An example known worldwide is the deforestation of the Amazon rainforest from the different countries that make it up, in which case the negative impact on the soils and the introduction to the jungle of external elements that are decimating endemic species and communities are evident. indigenous people who live in said area.[51]​.

Climate change manifests itself in increasingly stronger natural phenomena that largely threaten the lives of human beings. Likewise, soils and natural defenses are often increasingly reduced by the force of the impact, whether unprotected soils due to the felling of forests, increased temperatures due to the absence of trees, extinction of species, and limitations in crops due to flooding, among others. Indigenous peoples are in the midst of these havoc generated by the intervention of human beings on the earth.[51]​.

Sustainable development from the indigenous vision

In 2020, the United Nations and the Fund for the Development of the Indigenous Peoples of Latin America and the Caribbean (FILAC)[47]​ published a report on the objectives of sustainable development, which includes the most relevant issues in the relationship between indigenous peoples and the environment, with a view to an alternative development model to the current one.

Many indigenous peoples are economically sustainable even in the current century,[47]​ since they continue to produce their food, build their homes from the materials found in their ecosystems and manage their own system of justice and cultural continuity, despite the advances that humanity has experienced. For indigenous peoples, development does not represent the disappearance or predation of their natural environments or the alteration of ecosystems, since this goes against their belief systems and the level of knowledge that they have developed in this long path of interaction with the environment.[52]​ For this reason, international organizations such as the United Nations and FILAC have developed research and various efforts to propose new alternatives to current economic development and which were proposed in the Sustainable Development Goals. (SDG),[52]​ since this constitutes an opportunity to advance the dialogue between development models to implement more conscious and nature-friendly alternatives.

On June 5, World Environment Day is celebrated globally. This was established by the United Nations General Assembly in 1972. It is one of the important means by which the United Nations stimulates global awareness about the environment.

• - UNEP (United Nations Environment Programme).

• - BBC. Science and Nature.

• - Science.gov: Environment and Environmental Quality.

• - Environmental certification in Spain.

Earth sciences generally recognize the following four spheres as components of the systems that make up the entire natural environment:[8]​.

• - the lithosphere.

• - the hydrosphere.

• - the atmosphere.

• - the biosphere.

These spheres correspond to the set of rocks, waters, atmosphere and life, respectively.

Some scientists include, as part of the Earth's spheres, the cryosphere (corresponding to ice) as a distinct portion of the hydrosphere, as well as the pedosphere (corresponding to soil) as an active and intermingled sphere of the previous four.

Earth sciences (also known as geosciences or geological sciences) encompass all sciences related to the direct study of planet Earth as such. There are different disciplines in earth sciences, such as physical geography, geology, paleontology, geophysics, climatology, oceanography or geodesy, among others. These disciplines use physics, chemistry, biology, geochronology, and mathematics to develop a qualitative and quantitative understanding of the major areas or spheres of the Earth.

The Earth's crust ("Crust (geology)"), or lithosphere, is the outermost solid surface of the planet and is chemically and mechanically different from the underlying mantle. It is the rock layer of the Earth with which life and humans interact. It has been largely generated by igneous processes in which magma cools and solidifies to form solid rock. Below the lithosphere is the mantle that is heated by the decay of radioactive elements. The mantle, although solid, is in a state of rheological convection. This convection process causes the lithospheric plates to move, albeit slowly. The resulting process is known as plate tectonics. Volcanoes result primarily from the melting of subducted crustal or rising mantle material in mid-oceanic ridges and mantle plumes.

Contenido

La mayor parte del agua se encuentra en uno u otro tipo de cuerpo de agua natural.

Oceans

An ocean is a major body of saline water and a component of the hydrosphere. About 71% of the Earth's surface (an area of ​​about 362 million square kilometers) is covered by the ocean, a continuous body of water that is usually divided into several major oceans and smaller seas. More than half of this area is more than 3,000 meters (9,800 feet) deep. The average ocean salinity is about 35 ppt (parts per thousand) (3.5%), and almost all seawater has a salinity in the range of 30 to 38 ppt. Although generally recognized as several "separate" oceans, these waters comprise a global, interconnected body of salt water often known as the world ocean or the global ocean.[9]​[10]​ The deep seabed makes up more than half of the Earth's surface, and is among the least modified natural environments. The major oceanic divisions are defined in part by continents, various archipelagos, and other criteria: these divisions are (in descending order of size) the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Antarctic Ocean, and the Arctic Ocean.

Rivers

A river is a natural watercourse,[11]​ usually freshwater, that flows into an ocean, lake, sea or other river. A few rivers simply flow into the ground and dry up completely before reaching another body of water.

The water in a river is generally in a channel, formed by a stream bed between the banks "Bank (geography)"). In larger rivers there is also a wider floodplain formed by waters that cover the channel. Floodplains can be very wide relative to the size of the river channel. Rivers are part of the hydrological cycle. Water within a river is typically collected from precipitation (Precipitation (meteorology)), through surface runoff, groundwater recharge), springs, and the release of water stored in glaciers and snowpacks.

Small rivers may also be called by other names, such as stream. Its current is confined within a channel and a bank "Bank (geography)"). Currents play an important corridor role in connecting fragmented habitats and therefore in conserving biodiversity. The study of streams and watercourses in general is known as surface hydrology.[12]​.

Lakes

A lake (from Latin lacus) is a terrain feature, a body of water that is located at the bottom of the basin "Depression (geography)"). A body of water is considered a lake when it is inland, not part of an ocean, and is larger and deeper than a pond.[13]​[14]​.

Earth's natural lakes are generally found in mountainous areas, rift zones, and areas with recent or ongoing glaciations. Other lakes are found in endorheic basins or along the courses of mature rivers. In some parts of the world, there are many lakes due to the chaotic drainage patterns left over from the last Ice Age. All lakes are temporary on geologic time scales, as they will slowly fill with sediment or spill out. of the basin that contains them.

A pond is a body of standing water, whether natural or man-made, that is generally smaller than a lake. A wide variety of man-made bodies of water are classified as ponds, including water gardens designed for aesthetic ornamentation, fish ponds designed for commercial fish farming, and solar ponds designed to store thermal energy. Ponds and lakes are distinguished from streams by their current velocity. While currents in streams are easily observable, ponds and lakes possess thermal micro-currents and wind-moderated currents. These features distinguish a pond from many other aquatic terrain features, such as stream pools and tide pools.

Human impact on water

Humans impact water in different ways, such as modifying rivers (through dams and stream channeling), urbanization, and deforestation. These affect lake levels, groundwater conditions, water pollution, thermal pollution and marine pollution. Humans modify rivers using direct manipulation of channels.[15] They are building dams and reservoirs and manipulating the direction of rivers and the path of water. Dams are good for humans: some communities need reservoirs to survive. However, reservoirs and dams can negatively affect the environment and wildlife. Dams stop the migration of fish and the movement of organisms downstream. Urbanization affects the environment due to deforestation and change in lake levels, groundwater conditions, etc. Deforestation and urbanization go hand in hand. Deforestation can cause flooding, decreased stream flow, and changes in riverside vegetation. The change in vegetation occurs because when trees cannot obtain adequate water, they begin to deteriorate, leading to a decreased food supply for wildlife in an area.[15]​.

La atmósfera de la Tierra sirve como un factor clave para sostener el ecosistema planetario. La delgada capa de gases que envuelve a la Tierra se mantiene en su lugar por la gravedad del planeta. El aire seco consta de 78 % de nitrógeno, 21 % de oxígeno, 1 % de argón y otros gases inertes, como el dióxido de carbono. Los gases restantes a menudo se denominan gases traza,[17]​ entre los cuales se encuentran los gases de efecto invernadero, como el vapor de agua, el dióxido de carbono, el metano, el óxido nitroso y el ozono. El aire filtrado incluye trazas de muchos otros compuestos químicos. El aire también contiene una cantidad variable de vapor de agua y suspensiones "Suspensión (química)") de gotitas de agua y cristales de hielo vistos como nubes. Muchas sustancias naturales pueden estar presentes en pequeñas cantidades en una muestra de aire sin filtrar, incluyendo polvo, polen y esporas, rocío marino"), cenizas volcánicas y meteoroides. Varios contaminantes industriales también pueden estar presentes, tales como cloro (primario o en compuestos), compuestos de flúor, mercurio "Mercurio (elemento)") y azufre tales como dióxido de azufre (SO).

La capa de ozono de la atmósfera de la Tierra juega un papel importante en el agotamiento de la cantidad de radiación ultravioleta (UV) que llega a la superficie. Como el ADN se daña fácilmente con la luz UV, esto sirve para proteger la vida en la superficie. La atmósfera también retiene el calor durante la noche, lo que reduce las temperaturas diarias extremas.

Layers of the atmosphere

Earth's atmosphere can be divided into five main layers. These layers are determined primarily by whether temperature increases or decreases with altitude. From largest to smallest, these layers are:.

• - Exosphere: the outermost layer of the Earth's atmosphere extends from the exobase upwards, composed mainly of hydrogen and helium.

• - Thermosphere: the upper part of the thermosphere is the lower part of the exosphere, called the exobase. Its height varies with solar activity and ranges between 350-800 km (220-500 mi; ft). The International Space Station orbits in this layer, between 320 and 380 km (200 and 240 mi).

• - Mesosphere: The mesosphere extends from the stratopause to 80-85 km (50-53 mi; feet). It is the layer where most meteors burn up upon entering the atmosphere.

• - Stratosphere: The stratosphere extends from the tropopause to approximately 51 km (32 mi; ft). The stratopause, which is the boundary between the stratosphere and mesosphere, is usually 50 to 55 km (31 to 34 mi; ft).

• - Troposphere: The troposphere begins at the surface and extends to between 7 kilometers (22,965.9 feet) at the poles and 17 kilometers (55,774.3 feet) at the equator, with some variation due to climate. The troposphere is heated primarily by energy transfer from the surface, so on average the lower part of the troposphere is warmer and the temperature decreases with altitude. The tropopause is the boundary between the troposphere and the stratosphere.

Within the five main layers determined by temperature there are several layers determined by other properties.

• - The ozone layer is contained within the stratosphere. It is located mainly in the lower part of the stratosphere at approximately 15-35 km (9.3-21.7 mi; ), although the thickness varies seasonally and geographically. About 90% of the ozone in our atmosphere is contained in the stratosphere.

• - The ionosphere, the part of the atmosphere that is ionized by solar radiation, extends from 50 to 1000 km (31 to 621 mi; ) and generally overlaps both the exosphere and the thermosphere. It forms the inner edge of the magnetosphere.

• - The homosphere and the heterosphere: The homosphere includes the troposphere, the stratosphere and the mesosphere. The upper part of the heterosphere is composed almost entirely of hydrogen, the lightest element.

• - The planetary boundary layer is the part of the troposphere that is closest to the Earth's surface and is directly affected by it, mainly through turbulent diffusion.

The dangers of global warming are increasingly being studied by a large global consortium of scientists. These scientists are increasingly concerned about the possible long-term effects of global warming on our natural environment and the planet. Of particular concern are climate change and global warming caused by anthropogenic or man-made emissions of greenhouse gases, primarily carbon dioxide, which can act interactively and have adverse effects on the planet, its natural environment and the existence of human beings. It is clear that the planet is warming, and warming quickly. This is due to the greenhouse effect, caused by greenhouse gases, which trap heat within the Earth's atmosphere due to their more complex molecular structure that allows them to vibrate and, in turn, trap heat and release it back to the Earth.[18]​ This warming is also responsible for the extinction of natural habitats, which in turn leads to a reduction in wildlife populations. The most recent report from the Intergovernmental Panel on Climate Change (the group of the world's leading climate scientists) concluded that the earth will warm between 2.7 and almost 11 degrees Fahrenheit (1.5 to 6 °C) between 1990 and 2100.[19] Efforts have increasingly focused on mitigating the greenhouse gases that are causing climate change, developing adaptive strategies to global warming, and help humans, other animal and plant species, ecosystems, regions and nations adapt to the effects of global warming. Some examples of recent collaboration to address climate change and global warming include:.

• - The United Nations Framework Convention Treaty and the Convention on Climate Change, to stabilize greenhouse gas concentrations in the atmosphere at a level that prevents dangerous anthropogenic interference in the climate system.[20]​.

• - The Kyoto Protocol, which is the treaty protocol of the International Framework Convention on Climate Change, again with the goal of reducing greenhouse gases in an effort to prevent anthropogenic climate change.[21]​.

• - The Western Climate Initiative"), to identify, evaluate and implement collective and cooperative ways to reduce greenhouse gases in the region, focusing on a market-based cap-and-trade system.[22]​.

A significantly profound challenge is to identify natural environmental dynamics in contrast to environmental changes that are not within natural variations. A common solution is to adapt a static view that leaves out natural variations. Methodologically, this view could be defended when slowly changing processes and short time series are observed, while the problem arises when fast processes become essential in the object of study.

Climate

Climate analyzes the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle counts, and other weather elements in a given region over long periods of time. Weather, on the other hand, is the current condition of these same elements for periods of up to two weeks.

Climates can be classified according to the average and typical ranges of different variables, usually temperature and precipitation. The most widely used classification scheme is the one originally developed by Wladimir Köppen. The Thornthwaite system,[23]​ in use since 1948, uses evapotranspiration, as well as information on temperature and precipitation to study the diversity of animal species and the possible impacts of climate changes.[24]​.

weather

Weather is a set of all phenomena that occur in a given atmospheric area at a given time.[25]​ Most weather phenomena occur in the troposphere,[26][27]​ just below the stratosphere. Climate generally refers to daily temperature and precipitation activity, while climate is the term for average atmospheric conditions over longer periods of time.[28] When used without qualification, "climate" means the Earth's climate.

Climate occurs due to differences in density (temperature and humidity) between one place and another. These differences can occur due to the angle of the sun at any particular location, which varies depending on latitude from the tropics. The strong temperature contrast between polar and tropical air gives rise to the jet stream. Mid-latitude weather systems"), such as extratropical cyclones, are caused by the instability of the jet flow. Because the Earth's axis is tilted with respect to its orbital plane, sunlight hits it at different angles at different times of the year. At the Earth's surface, temperatures typically range between ±40 °C (100 °F to −40 °F) annually. For thousands of years, changes in the Earth's orbit have affected the amount and distribution of solar energy received by the Earth and influence the long-term climate.

Temperature differences at the surface in turn cause pressure differences. Higher altitudes are colder than lower altitudes due to differences in compressional heating. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and location. The atmosphere is a chaotic system, and small changes in one part of the system can grow to have large effects on the system as a whole. Human attempts to control the climate have occurred throughout human history, and there is evidence that civilized human activity, such as agriculture and industry, has inadvertently modified weather patterns.

Evidence suggests that life on Earth has existed for about 3.7 billion years.[29] All known life forms share fundamental molecular mechanisms, and based on these observations, theories of the origin of life attempt to find a mechanism that explains the formation of a single-celled primordial organism, from which all life originates. There are many different hypotheses regarding the route that could have been taken from simple organic molecules through precellular life to protocells and metabolism.

Although there is no universal agreement on the definition of life, scientists generally accept that the biological manifestation of life is characterized by organization, metabolism, growth, adaptation, response to stimuli, and reproduction.[30] It can also be said that life is simply the characteristic state of organisms. In biology, the science of living organisms, "life" is the condition that distinguishes active organisms from inorganic matter, including the capacity for growth, functional activity, and the continuous change that precedes death.[31][32]​.

A diverse variety of living organisms (life forms) can be found in the biosphere on Earth, and the common properties of these organisms (plants, animals, fungi, protists, archaea, and bacteria) are a carbon- and water-based cellular form, with complex organization and heritable genetic information. Living organisms have a metabolism, maintain homeostasis, have the capacity to grow, respond to stimuli, reproduce and, through natural selection, adapt to their environment in successive generations. The most complex living organisms can communicate through various means.

An ecosystem (sometimes used with the same meaning as environment) is a natural unit consisting of all plants, animals and microorganisms (biotic factors) in an area that function together with all non-living physical (abiotic) factors of the environment.[33]​.

Fundamental to the concept of ecosystem is the idea that living organisms are continually engaged in a set of highly interrelated relationships with all the other elements that constitute the biophysical environment in which they exist. Eugene Odum, one of the founders of the science of ecology, stated:

Any unit that includes all organisms (i.e., the "community") in a given area that interacts with the physical environment so that a flow of energy clearly leads to defined trophic structure, biotic diversity, and material cycles (i.e., the exchange of materials between living and non-living parts) within the system is an ecosystem.[34]​.

The concept of the human ecosystem is then based on the deconstruction of the human/nature dichotomy, and the emerging premise that all species are ecologically integrated with each other, as well as with the abiotic constituents of their biotope.

A greater number or variety of species or the biodiversity of an ecosystem can contribute to a greater capacity for ecosystem recovery, because there are more species present in a place to respond to change and, therefore, "absorb" or reduce its effects. This reduces the effect before the ecosystem structure is fundamentally changed to a different state. This is not universally the case and there is no proven relationship between the species diversity of an ecosystem and its ability to provide goods and services at a sustainable level.

The term ecosystem can also refer to man-made environments, such as human ecosystems and human-influenced ecosystems, and can describe any situation in which there is a relationship between living organisms and their environment. Today, there are fewer areas on the earth's surface free of human contact, although some natural or wild areas continue to exist without any form of human intervention.

Biomes are terminologically similar to the concept of ecosystems, and are climatically defined geographically defined areas of ecologically similar climatic conditions on Earth, such as communities of plants, animals, and soil organisms, often referred to as ecosystems. Biomes are defined based on factors such as plant structures (such as trees, shrubs and grasses), leaf types (such as leaf width and different parts), plant spacing (in forests, savannahs) and climate. Unlike ecozones, biomes are not defined by genetic, taxonomic, or historical similarities. Biomes are often identified with particular patterns of ecological succession and culminating vegetation.

Global biogeochemical cycles are critical for life, especially those of water, oxygen, carbon, nitrogen and phosphorus.[35]​.

• - The nitrogen cycle is the transformation of nitrogen and nitrogen-containing compounds in nature. It is a cycle that includes gaseous components.

• - The water cycle is the continuous movement of water on, above and below the Earth's surface. Water can change states between liquid, vapor, and ice at various places in the water cycle. Although the balance of water on Earth remains fairly constant over time, individual water molecules can come and go.

• - The carbon cycle is the biogeochemical cycle by which carbon is exchanged between the biosphere, pedosphere, geosphere, hydrosphere and atmosphere of the Earth.

• - The oxygen cycle is the movement of oxygen within and between its three main reservoirs: the atmosphere, the biosphere and the lithosphere. The main determining factor of the oxygen cycle is photosynthesis, responsible for the atmospheric composition and life of the modern Earth.

• - The phosphorus cycle is the movement of phosphorus through the lithosphere, hydrosphere and biosphere. The atmosphere does not play a major role in phosphorus movements, because phosphorus compounds are generally solid in the typical temperature and pressure ranges found on Earth.

Wilderness is generally defined as a natural environment on Earth that has not been significantly modified by human activity. The WILD Foundation goes into more detail, defining wildlife as:.

Protected wilderness areas and parks are considered important for the survival of certain species, ecological studies, conservation, solitude and recreation. The desert is deeply valued for cultural, spiritual, moral and aesthetic reasons. Some nature writers believe that wilderness areas are vital to the human spirit and creativity.[37]​.

The word "savage" derives from the notion of savagery; in other words, what is not controllable by humans. The etymology of the word wild comes from the Old English wildeornes, which in turn is derived from wildeor, meaning wild 'beast' (wild = 'wild' + deor = 'beast, deer').[38]​ From this point of view, it is the wild nature of a place that makes it a wilderness. The mere presence or activity of people does not disqualify an area from being "desert." Many ecosystems that are, or have been, inhabited or influenced by the activities of people can still be considered “wild.” This way of viewing the desert includes areas within which natural processes operate without much noticeable human interference.

Wildlife includes all non-domesticated plants, animals and other organisms. The domestication of wild plant and animal species for human benefit has occurred many times across the planet and has a large impact on the environment, both positive and negative. Wildlife can be found in all ecosystems. Deserts, rainforests, plains and other areas, including more developed urban sites, have distinct forms of wildlife. While the term in popular culture usually refers to animals that are not affected by civilized human factors, most scientists agree that wildlife around the world is (now) affected by human activities.

It is the common understanding of the "natural environment" that underlies environmentalism: a broad political, social and philosophical movement that advocates various actions and policies in order to protect what nature remains in the natural environment, or restore or expand the role of nature in this environment. While true wilderness is increasingly rare, wild nature (e.g., unmanaged forests, uncultivated grasslands, wildlife, wildflowers) can be found in many places previously inhabited by humans.

Goals for the benefit of people and natural systems, commonly expressed by environmental scientists and environmentalists, include:

• - Elimination of pollution and toxics in air, water, soil, buildings, manufactured products and food.

• - Preservation of biodiversity and protection of endangered species.

• - Conservation and sustainable use of resources such as water,[41] land, air, energy, raw materials and natural resources.

• - Stop human-induced global warming, which represents pollution, a threat to biodiversity and a threat to human populations.

• - Switching from fossil fuels to renewable energy in electricity, heating and cooling, and transportation, addressing pollution, global warming, and sustainability. This may include public transportation and distributed generation, which have benefits for traffic congestion and electrical reliability.

• - Shifting from meat-intensive diets to largely plant-based diets to help mitigate biodiversity loss and climate change.[42]​.

• - Establishment of nature reserves for recreational purposes and preservation of ecosystems.

• - Sustainable and cleaner waste management, including waste reduction (or even zero waste), reuse, recycling, composting, waste-to-energy and anaerobic digestion of sewage sludge.

• - Slowing and stabilization of human population growth.[43]​.

En algunas culturas, el término entorno carece de significado porque no hay separación entre las personas y lo que ellos ven como el mundo natural o su entorno.[44]​ Específicamente en los Estados Unidos, muchas culturas nativas no reconocen el «ambiente», o se ven a sí mismas como ambientalistas.[45]​.

Environment and indigenous peoples

Indigenous peoples are local communities that inhabit 22% of the planet's territory and have a population of between 350 and 500 million people around the world.[46] These populations were historically established in various territories throughout the planet, in which they adapted and created a close relationship between the individual and the inhabited ecosystem. In this adaptation process, indigenous peoples were modifying and creating an entire symbolic world between the environment and people, to the point of becoming or recognizing themselves as part of the natural ecosystem they inhabit; This statement is supported by oral stories transmitted through generations, which subsequently derived and contributed to the development of their identity processes;[47]​ This is why there are indigenous communities that recognize themselves as descendants of beings, animals and any other element of nature.

Currently, the super population and the increase in demands on natural resources have pushed large raw material extraction companies to search, negotiate and exploit new territories in the search for fertile lands suitable to continue generating resources for large industries worldwide.[48] This situation has led to the confrontation of the ways of understanding and seeing the world by Western peoples and indigenous and local peoples, which has generated asymmetrical interethnic relations with long-term repercussions for the groups involved.

Given the relationship between indigenous peoples and the environment, these human groups are recognized as the guardians of natural ecosystems, since they consider it part of their culture and the conducive home for the continuity of their cultural practices and customs.[49]​ This is why any attack on the natural system and indigenous territories directly threatens life and the continuity of indigenous ways of life.

Climate change and indigenous peoples

Indigenous peoples, as a result of their close connection with their territories, are being impacted and affected by the changes that are occurring in the climate and the increase in temperatures worldwide, either through periods of rain above normal and the worsening of drought in arid areas. The appearance of new viruses and the extinction of local fauna species.[50]​ Situation that directly attacks their economic systems and generates an exodus and mobilization of indigenous groups to urban areas.[50]​ An example known worldwide is the deforestation of the Amazon rainforest from the different countries that make it up, in which case the negative impact on the soils and the introduction to the jungle of external elements that are decimating endemic species and communities are evident. indigenous people who live in said area.[51]​.

Climate change manifests itself in increasingly stronger natural phenomena that largely threaten the lives of human beings. Likewise, soils and natural defenses are often increasingly reduced by the force of the impact, whether unprotected soils due to the felling of forests, increased temperatures due to the absence of trees, extinction of species, and limitations in crops due to flooding, among others. Indigenous peoples are in the midst of these havoc generated by the intervention of human beings on the earth.[51]​.

Sustainable development from the indigenous vision

In 2020, the United Nations and the Fund for the Development of the Indigenous Peoples of Latin America and the Caribbean (FILAC)[47]​ published a report on the objectives of sustainable development, which includes the most relevant issues in the relationship between indigenous peoples and the environment, with a view to an alternative development model to the current one.

Many indigenous peoples are economically sustainable even in the current century,[47]​ since they continue to produce their food, build their homes from the materials found in their ecosystems and manage their own system of justice and cultural continuity, despite the advances that humanity has experienced. For indigenous peoples, development does not represent the disappearance or predation of their natural environments or the alteration of ecosystems, since this goes against their belief systems and the level of knowledge that they have developed in this long path of interaction with the environment.[52]​ For this reason, international organizations such as the United Nations and FILAC have developed research and various efforts to propose new alternatives to current economic development and which were proposed in the Sustainable Development Goals. (SDG),[52]​ since this constitutes an opportunity to advance the dialogue between development models to implement more conscious and nature-friendly alternatives.

On June 5, World Environment Day is celebrated globally. This was established by the United Nations General Assembly in 1972. It is one of the important means by which the United Nations stimulates global awareness about the environment.

• - UNEP (United Nations Environment Programme).

• - BBC. Science and Nature.

• - Science.gov: Environment and Environmental Quality.

• - Environmental certification in Spain.