【Reading Notes】CH Beck - Kulturgeschichte des Klimas 1

Climate Archives

The study of climate archives has advanced greatly due to the discovery of radioactive phenomena. The nuclei of many elements are unstable and emit radiation when they decay. The content of parent element and child element can be measured by mass spectrometer. Since the half-life of each element is specific, this allows for dating. If you know the chemical properties of the various minerals and the melting point of the rock, plus the dating results based on the half-life, you can infer the time when the rock cooled and formed.
The past temperature of seawater can be inferred from the isotopes of oxygen. The oxygen atom generally contains 8 neutrons, namely O-16; its isotope, O-18, contains 10 neutrons. Depending on the temperature, these oxygen atoms accumulate in marine organisms. The content of heavy oxygen increases as the temperature decreases. This method is of great significance to the study of ice age.
Sediments can not only provide information on paleoclimate, but also contain volcanic deposits, animal and plant remains, etc. The development of river stages and soils is also climate-related. Glacial remnants are also valuable climate archives. Deep-sea drilling techniques and polar ice cores can also provide information about paleoclimate. Oxygen isotope methods can also be used for polar ice cores, and analysis of "paleo-air" preserved in ice core bubbles can reveal the composition of the previous atmosphere, such as how carbon dioxide levels have changed over time. Analysis of sulfides can infer volcanic activity.
In addition, deposits of clay minerals, pollen deposits, moraine left by glaciers, tree rings, etc. can all become paleoclimate archives.
Human temperature measurement began in Galileo, and it was only in 1870 that humans collected enough data to infer the average global temperature.

causes of climate change

The author cites four main reasons. The first is solar activity. Of course, the sun is the energy source of the earth, and the activities of the sun itself, such as sunspots, will definitely affect the earth. The Yugoslav astronomer Milankovic tried to explain the glacial phenomenon in terms of the eccentricity and inclination of the Earth's orbit (saying that Schad was recently introduced to this cycle in a soil science class). He calculated that the Earth's axis of rotation and the inclination of its orbital plane wobbled in cycles of 41,000 years. The current dip is about 23.44 degrees, meaning the temperature difference between winter and summer is relatively small.
The second reason is the state of the Earth's own atmosphere, which is the greenhouse effect, both natural and man-made. Human activities have caused an increase in carbon dioxide levels in the atmosphere. Not only the burning of fossil fuels, the relatively low levels of carbon dioxide during the ice age but also because of the high forest cover, carbon atoms were fixed within the biomass of trees. At the end of the 19th century, the carbon dioxide content of the Earth's atmosphere was about 230 ppM, and by the end of the 20th century this value rose to 350 ppM. But whether the rise in carbon dioxide levels is causing the planet to warm, or whether the warming of the planet is causing the rise in carbon dioxide levels, is still controversial in the scientific community. Perhaps this is also an interactive process.
The third reason is the plate movement of the earth, which determines the location of sea and land, as well as topography, which have a major impact on climate, especially within topography. For example, the polar regions are covered by glaciers, so Albedo (reflectivity of solar radiation) is high, which is why glaciers have an important role in regulating the Earth's climate. If the glacier area shrinks, the Albedo will decrease, the solar radiation absorbed by the earth will increase, and the temperature will increase, which will cause more glaciers to melt. This is a feedback effect.
Volcanoes are also a destabilizing factor in Earth's climate. Volcanic ash, aerosols and volcanic gases affect Earth's atmosphere. If the earth's atmosphere is covered with volcanic ash, solar radiation cannot reach the earth's surface well, which may cause the earth's temperature to drop for a short time. It is speculated that the Tambora eruption in Indonesia in 1815 caused global climate anomalies and crop failures in many areas.

About "Paleoclimate"

Geologically, an ice age is defined as the presence of glaciers in the polar and alpine regions. So, as weird as it sounds, geologically we do live in an ice age. Ice ages are further divided into glacial periods and interglacial periods. Interglacial periods are the warmer ages between the two glacial periods. To be precise, we are living in an interglacial period. But this is actually a special state of the earth, because permanent glaciers do not exist on Earth more than 95% of the time, and warmer climates dominate.
Geochronology divides Earth's history into different eons (Äon), generations (Ära), periods (Periode), epochs (Epoche), and periods (Alter). The division of the four "universes" is based on the conditions for the existence of life on the earth. At the beginning of the Hadaikum (Hadaikum), there was no atmosphere at the beginning of the formation of the earth, and the basic conditions for the existence of life were lacking. Due to geothermal activity, the Earth's temperature is higher than in any period since. About 4 billion years ago, the temperature near the crust gradually dropped below 100 degrees, and water vapor could condense, thus forming mountains, rivers, lakes, seas and rain. About 3.8 billion to 2.5 billion years ago, during the Archaikum, the earth gradually formed a relatively stable ancient atmosphere. At that time, the atmosphere was very high in carbon dioxide, so the greenhouse effect was very strong, and the warm environment made possible the emergence of the first life forms, namely archaea. Scientists have found evidence of a water cycle that existed at that time in rock specimens dating back 3.2 billion years. 2.6 billion years ago, cyanobacteria (cyanobacteria) had already produced oxygen through photosynthesis. The carbon dioxide-based atmosphere slowly disintegrated, and anaerobic life forms gradually died. This was the first mass extinction event on earth.
In the following Proterozoikum, plants initially with nuclei gradually formed. Single-celled and multicellular soft-bodied organisms arose about 1.4 billion years ago. The major land masses on Earth at that time were joined together and called Rodinia. Slowly the continent of Rodinia disintegrated, and the land masses gathered in the equatorial region. Large swaths of unvegetated rock increase the reflectivity of solar radiation, and glaciers appear in the polar regions and slowly expand across the globe. A second mass extinction event occurred around 650 million years ago due to cooler temperatures.
Regarding the mass extinction, the more famous one is the five times of the Phanerozoikum, namely the Big Five. I'll have the opportunity to add this later. Regarding the aforementioned Rodinia continent, after it disintegrated, two supercontinents, Gondwana and Laurasia, were slowly formed, as well as various land masses. During the Carboniferous period of the Phanerozoic Era, these continents and blocks merged together due to the action of plate movement, called Pangea (Pangäa) (this translation is really Xindaya!).