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.