Climate change — long-term (over 10 years) are intended or rhythmic changes in the climate on the Earth as a whole or in its major regions. Climate change directly or indirectly to human activity that alters the composition of the global atmosphere.
Adverse effects of climate change involves changes in the physical environment or biota resulting from climate change which have significant deleterious effects on the composition, resilience or productivity of natural and managed ecosystems or on the operation of socio-economic systems or on human health and welfare.
Climate change can be somewhat conventionally divided into the long-period, short-period and rapid, occurring in a very short time compared to the characteristic time of changes in the socio-economic sphere. They each have their own reasons for which a number of hypotheses.
Some of the available hypotheses are based on the potential impact on the climate system extraterrestrial factors: changes in solar activity, especially the orbital motion of the Earth, meteorites fall, change in position of the magnetic poles of the Earth. Others try to explain the instability of the climate effect of internal reasons, such as: an increase of volcanic activity, changes in the concentration of carbon dioxide in the atmosphere, changes in the system of ocean currents, the natural oscillations of the atmospheric circulation.
Sun — is the main force manages the climate system, and even the slightest changes in solar radiation can have serious consequences for the climate of the earth. For many years, scientists believed that the solar activity remains constant. However, satellite observations have questioned the validity of this hypothesis.
Solar activity increases and decreases every eleven years (or, as some experts, every twenty-two years) of the solar cycle. There may be other important solar cycles. In order to assess their impact, it is necessary to carry out continuous measurements of solar activity and study traces the interaction between solar activity and climate over the past century and millennium.
Astronomical factors: In the middle of XX century, scientists have found that over millions of years, the strongest influence on the climate of the Earth is periodic changes in its orbit. Over the last 3 million years of regular oscillations of sunlight falling on the surface of the planet, caused a series of ice ages, punctuated by brief warm interglacial intervals.
One of the most well-known and widely accepted theory of the periodic freezing of the Earth is an astronomical model, proposed in 1920 by the Serbian geophysicist Milutin Milankovitch. In accordance with the hypothesis of Milankovitch Hemisphere by changing its motion may receive greater or lesser amount of solar radiation that is reflected in the global temperature.
Over millions of years, replaced many climatic cycles. At the end of the last ice age, ice, over 100 thousand years fetter the north of Europe and North America began to decline, and 6000 years ago has disappeared. Many scientists believe that the development of civilization has basically a warm interval between ice ages.
Composition of the atmosphere: The atmosphere is heated by absorbing solar radiation as well as the natural radiation the surface. The heated atmosphere radiates herself. As well as the earth's surface, it emits infrared radiation in the range of long wavelengths invisible to the eye. A significant proportion (70%) of atmospheric radiation comes to the surface, it is almost entirely absorbed (95-99%). This radiation is called "counter-radiation", as it is directed toward the self-radiation ground. The main substance in the atmosphere that absorbs terrestrial radiation and sends a counter, is water vapor.
In addition to the water vapor in the atmosphere are carbon dioxide (CO2) and other gases that absorb energy in the wavelength range 7-15 microns, ie where the energy of the earth's radiation is close to the maximum. Relatively small changes in the concentration of CO2 in the atmosphere can affect the temperature of the earth's surface. By analogy with the processes occurring in greenhouses, where penetration through the protective film radiation heats the earth, the radiation of which the film is delayed, providing additional heating, the process of interaction between the surface and the atmosphere is called the "greenhouse effect."
The phenomenon of the greenhouse effect keeps the Earth's surface temperature is a risk of the emergence and development of life. If the greenhouse effect, the average temperature of the earth would be much lower than it is now.
The influence of external factors on the global air temperature is studied through simulation. Most of the work in this area indicate that in the last 50 years, the estimated rate and magnitude of warming due to increasing greenhouse gases, it is comparable to the rate and extent of the observed warming or exceed them.
Changes in atmospheric concentrations of greenhouse gases and aerosols, changes in solar radiation and land surface properties alter the energy balance of the climate system. These changes are expressed by the term "radiative forcing", which is used to compare how, for a number of human and natural factors on the global climate is heating or cooling effect.
Other obvious causes of climate change, is the eruption of volcanoes. This possibility was discussed in the XVII century by Benjamin Franklin. The idea was that formed during the eruption cloud of small particles (aerosols) can significantly impair the flow coming to the surface shortwave radiation, almost without changing the long-wave radiation, passing into space. Further studies showed that the main influence on the radiation and thermal regime of the Earth has a layer of sulfuric acid aerosol formed in the stratosphere of the volcano ejected sulfur gases. Of greatest interest is the impact of volcanic eruptions on the air temperature. From general considerations, experts expect a drop in temperature over time.
The oceans also play an important role in the global climate system. The atmosphere has a common border with the ocean by more than 72% of the Earth's surface and responds to the changes occurring in the ocean. It must be remembered also that at any time the amount of heat stored in the vertical atmospheric column height from the Earth's surface to the boundaries of space, about the same as contained in the water column of the ocean height of 3 m, measured from the surface. Therefore, it is the ocean is the main battery and the keeper of the energy reaching the Earth solar radiation, which was later released into the atmosphere.
With large heat capacity, the oceans have a stabilizing effect on the atmosphere, making it more stable. At the same time, and the main parameters of the oceans have long-period and short-period changes, and some of them in their time characteristics are comparable to the changes occurring in the atmosphere.
The current weather conditions are largely due to the influence of the ocean. The stock of heat in the ocean is placed evenly and constantly moving ocean currents.
In addition to continuing the heat transfer surface currents in the ocean is a regular mixing water depth, known as the "thermohaline circulation", depending on the temperature of the water, and on its content of salt, or salinity salt water freezes at a lower temperature.
According to a study of Danish scientists, Earth's magnetic field also has a significant impact on the climate, and this may lead to a revision of assumptions about the fact that the primary responsibility for global warming are greenhouse gases.
According to the IPCC assessment report in 2007, with a probability of 90% of the observed changes in climate associated with human activities. Such a hypothesis was proposed in 1992 to the UN Framework Convention on Climate Change.
Anthropogenic origin of modern climate change, in particular, confirm the paleoclimatic studies based on the analysis of greenhouse gases in the air bubbles, frozen in the ice. They show that this concentration of CO2 as now was not the last 650,000 years. In comparison with pre-industrial levels (1750), the concentration of carbon dioxide in the atmosphere has increased by a third. Current global methane and nitrous oxide are also significantly higher than pre-industrial values.
The increasing concentration of the three main greenhouse gases from the mid 18th century, according to scientists, with very high probability associated with human activities, in the first place — the carbon burning of fossil fuels (oil, gas, coal, etc.), industrial processes, and as deforestation — sinks of CO2 from the atmosphere.
Global climate change will redevelop all geosystems. These observations suggest an increase in sea levels, melting glaciers and permafrost, increasing irregularity of rainfall, change in river flows and other global changes related to climate variability.
Effects of climate change are already evident today, including in the form of increased frequency and intensity of severe weather events, the spread of infectious diseases. They cause significant economic damage, threatening the existence of stable ecosystems, and human health and life. Conclusions of the scientists say that the ongoing climate changes in the future may lead to even more dangerous consequences if humanity fails to take appropriate preventive measures.
As can be seen from the article, the weather and climate affect many factors. It is therefore very important to monitor their changes before any important undertaking. To everything you need to prepare very thoroughly! For example, it is necessary to explore the most popular attractions in Europe before heading to a similar holiday. After all, a lot of interest, and would like to see them all. But as we all have limited time and finances, the main thing to choose the most interesting!