Information Retrieval about the Contribution of Volcanic Activity and CO2 Concentration Increase to the Climate Variability

Successive filtration was used in this paper to analyze the contribution of volcanic activity and CO2 concentration increase to the climate variability. According to the comparison, the surface air temperature in the Northern Hemisphere (NH) in July has continuously increased during the past century, which is associated to the increases in greenhouse gases mostly CO2 and in volcanic activity, demonstrating that: A. The variation in the surface air temperature is approximately out of phase with that of the volcanic activity index. In other words, when volcanic activity occurs frequently, a cooling in the NH surface layer corresponds; and on the contrary, the inactive volcanic activity corresponds to a warming event. The variation in volcanic activity strongly impacts the variation in the surface air temperature, the variance contribution of which is 39.22%. B. The increase in CO2 concentration is largely consistent with that of the summer surface air temperature in the NH. However, the increase in the air temperature is not in a linear pattern, during which several cooling events interrupts. The cooling event during early 20th century is a remarkable one, so are the ones between 1950s and 1970s. Analysis shows that these events are induced by volcanic activity. The variance of contribution of CO2 variation is 38.55%. C. The variation in CO2 concentration and the volcanic activity has a significant influence on the variation in surface air temperature of the NH. The variance contribution of the two factors reaches 77.76%.