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The majority of respondents had expected some warming to occur between 1970 and 2000, and described human emissions of carbon dioxide as the primary cause, but there was a disagreement on the extent, and a few had thought that an increase in volcanic activity would offset carbon dioxide emissions by elevating atmospheric sulfate concentrations ...
Total atmospheric mass is 5.1480×10 18 kg (1.135×10 19 lb), [42] about 2.5% less than would be inferred from the average sea level pressure and Earth's area of 51007.2 megahectares, this portion being displaced by Earth's mountainous terrain. Atmospheric pressure is the total weight of the air above unit area at the point where the pressure ...
Although various proxies for past atmospheric CO 2 levels in the Eocene do not agree in absolute terms, all suggest that levels then were much higher than at present. In any case, there were no significant ice sheets during this time. [13] Earth surface temperatures increased by about 6 °C from the late Paleocene through the early Eocene. [13]
The carbon dioxide levels necessary to thaw Earth have been estimated as being 350 times what they are today, about 13% of the atmosphere. [63] Since Earth was almost completely covered with ice, carbon dioxide could not be withdrawn from the atmosphere by release of alkaline metal ions weathering out of siliceous rocks.
The Great Oxidation Event (GOE) or Great Oxygenation Event, also called the Oxygen Catastrophe, Oxygen Revolution, Oxygen Crisis or Oxygen Holocaust, [2] was a time interval during the Earth's Paleoproterozoic era when the Earth's atmosphere and shallow seas first experienced a rise in the concentration of free oxygen. [3]
Ocean acidification means that the average seawater pH value is dropping over time. [1]Ocean acidification is the ongoing decrease in the pH of the Earth's ocean.Between 1950 and 2020, the average pH of the ocean surface fell from approximately 8.15 to 8.05. [2]
By the early 1980s, the slight cooling trend from 1945 to 1975 had stopped. Aerosol pollution had decreased in many areas due to environmental legislation and changes in fuel use, and it became clear that the cooling effect from aerosols was not going to increase substantially while carbon dioxide levels were progressively increasing.
Arrhenius was the first to use the principles of physical chemistry to estimate the extent to which increases in the atmospheric carbon dioxide are responsible for the Earth's increasing surface temperature. His work played an important role in the emergence of modern climate science. [6]