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Summary Climate Change
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Summary of the most important facts and content related to climate change.
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CAUSES OF CLIMATE CHANGES climate – the average state of the atmosphere over a certain area
climate change - all possible forms of climate instability
climate fluctuation – instability of the climate consisting of any form of systematic change
climatic oscillation – proper climatic fluctuation
climate is much more difficult to determine than time, climate changes are not easily observable
previously, scientists believed that the climate is unchanging and that by measuring the elements over a
longer period, the "normal" value of an individual element will be obtained
for the Krapin Neanderthal about 130,000 years ago, the average annual temperature was about 5 °C
higher
natural factors
Milanković's cycles - Serbian mathematician Milutin Milanković from the first half of the 20th
century.
– three orbital parameters of the Earth change cyclically
– different intensity of solar radiation in different parts, different heating of the planet
– pointed out that all these orbital changes have very little effect on the total annual amount of
energy that the Earth receives from the Sun
– he believed that these changes cause significant differences in the distribution of solar energy
by season and at different latitudes
– this theory does not answer all questions, primarily why such glacial and interglacial changes
were not recorded before the Quaternary, and there were orbital changes
– does not explain the gradual drop in temperature during the Quaternary (each glacial and
interglacial slightly colder than the previous one)
– Milanković's calculations say that the last w ü is Roman glacial lasted 144,000-21,000 years ago,
solar radiation
and evidence says it lasted 70,000-10,000 years ago
– Milanković emphasizes the different intensity of warming in different latitudes and points out
that cooling in higher latitudes was followed by warming in lower latitudes
– paleoclimatological evidence speaks of cooling throughout the Earth, and even in the tropics
a) axial precession – the Earth's axis rotates like a spinning wheel in a period of 25,800 years –
Plato's year
– the change in the direction of the Earth's axis in relation to the stars
– if we pass through the perihelion and aphelion around the solstice, the seasonal differences
between the seasons will be more pronounced in one hemisphere compared to the other
– if we pass through perihelion and aphelion around the equinoxes, the seasonal contrasts will be
equal in both hemispheres
– today the Earth is at perihelion on January 3, and at aphelion on July 4, so the seasons in the
southern hemisphere are somewhat more extreme than in the northern
b) change in the tilt of the axis of rotation - in relation to the orbital plane 22.1 - 24.5° in 45,000
years
– increasing the angle of inclination increases the amplitude of the seasonal cycle of insolation:
summers are hotter and winters are colder current inclination 23.4°
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, c) change in the eccentricity of the Earth's orbit around the Sun - the shape changes from an
almost regular circle (eccentricity 0.005) to an ellipse (eccentricity 0.068) in a period of 100,000
years
– at the highest eccentricity, the amount of received radiation in aphelion (the position when the
Earth is farthest from the Sun) and perihelion (the position when the Earth is closest to the Sun)
differs by 30 %
– the current eccentricity is 0.017
glacial and interglacial changes within the glaciation
the Pliocene -Quaternary glaciation begins at the end of the Pliocene and continues today,
we live in an ice age
glacials and 5 interglacials took place
modern man lives in an interglacial
INTENSITY OF SOLAR RADIATION
Solar radiation represents the entire spectrum of electromagnetic radiation coming from the
Sun
Sunspots - darker and colder areas on the surface of the Sun with an average temperature of
about 4000 °C, and the rest has a temperature of 6000 °C
– appearance and origin are related to the influence of strong magnetic fields
– they most often appear in cycles that last 11, 22 or 80-90 years
– the greater the number of spots, the stronger the radiation intensity, because then the
surrounding areas are brighter and warmer
– during the extremely warm period of 900-1100 there were many sunspots
– 1430 – 1850, less number of sunspots, little ice age
– 1645 – 1715 no Sunspots at all – Maunder minimum the strongest winters
– 1790 – 1830 cooling again – Dalton minimum
– 1950s more than 200 spots temperature rise - Modern maximum
aerosols - reaches the upper layers of the atmosphere
aerosols can cause an increase in temperature because they absorb solar radiation well, and it is
very difficult to pass terrestrial radiation and thus prevent heat loss
volcanic eruptions
an excessive amount prevents the penetration of the Sun's short-wave radiation and reduces
the temperature
aerosols are created by the blowing of particles by wind from deserts, eruptions or forest fires
– most associated with anthropogenic impact via fossil fuel combustion or industry
eruption of Toba in Sumatra about 75,000 years ago "volcanic winter" 5-10 years +
consequences
8/26/1883, the strongest recorded eruption in geological history on the Indonesian island of
Krakatau
– the new island of Anak Krakatau was created
tectonics
orogeny (collision) – convergent boundary of lithospheric plates
oceanization (spreading) – divergent boundary of lithospheric plates
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, ANTHROPOGENIC FACTORS
fossil fuels – irreplaceable raw materials in transport, energy and industry, products of CO2 and N2 O
combustion
– as much as 95% of the burning of fossil fuels refers to the northern hemisphere, where the
concentration of CO2 is 2 ppm higher
deforestation increases the CO2 concentration
– in densely populated areas due to living space: settlements, roads, agricultural areas
– in tropical rain forests due to the profit from quality species: ebony, sandalwood, mahogany
– by absorbing CO2 in photosynthesis, forests contribute to regulating its concentration
– felling additionally releases the carbon stored in the trees
– decrease in rainfall due to less evaporation
intensive agriculture - nitrogen oxides, the greenhouse effect, are released from artificial fertilizers
global warming - gradual warming of the lower layers of the atmosphere due to the greenhouse effect
– associated with anthropogenic emissions of greenhouse gases
– it begins with the industrial revolution at the end of the 18th century, and continues today
fast-growing urbanization, concreting, asphalt surfaces urban center "heat islands"
ACID RAINFALL
acid precipitation - any precipitation with a pH value below 5
lowering of pH is caused by nitrogen and sulfur oxides from households, industry, and car exhaust
gases
non-metallic oxides in a humid atmosphere react with water vapor, nitric and sulfuric acids
acid in the soil dissolves nutrients such as calcium, which is important for plant growth and
development
damages the roots of trees or reaches the leaves or needles of trees through rainfall and damages plant
tissue
brown spots appear on the plants and drying occurs
the seas are becoming increasingly acidic and poorer in oxygen as a result of the dissolution of CO 2 in
the oceans
after the last ice age, the pH of the ocean was 8.3, and today it has dropped to 8.1
the pH will be 7.4 in 2300
– negative effect on organisms with a CaCO3 skeleton that dissolves in acids
since the 1980s, biological productivity has decreased by 6%
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