Abstract: The atmosphere CO₂ gas, solar activity and volcanic eruptions are three major climate forcing. By comparing the climate forcing with the hierarchical structure of hemisphere surface temperature variations during last a hundred years, the possible external cause of the hemisphere surface temperature jump change has been investigated. For abrupt change of long-term climate in the northern hemisphere in 1924 (its timescale is about 77 years) and southern hemisphere in 1939 (its timescale is about 90 years), the greenhouse effect of atmosphere CO₂ gas is unimportant forcing. It is not very possibly caused by the obvious change in astronomical solar constant. For abrupt change of short-term climate in the northern hemisphere before 1924, there is evident corresponding of middle cool/warm period (its timescale is about 14 years) to frequently large volcanic eruptions on the low and middle/the middle and high latitude. The jump changes appeared in the southern hemisphere short-term climate (its timescale is about 5.6 years) is strongly influenced by the solar activity.

Key words: cold period, warm period, hierarchical structure, climate jump change

摘要： 利用近百年来大气中CO₂含量、太阳活动和强火山活动的历史资料，对照南北半球气温变化的层次结构，发现北半球在1924年、南半球在1939年发生的大尺度冷暖突变，CO₂气体的温室效应不是主要的强迫因素，也不太可能是由太阳常数的较大天文改变引起的，它与强火山活动有着密切关系。北半球1924年前的大冷期内中等冷期对应着中低纬强火山爆发，中等暖期对应着中高纬强火山爆发，对应关系明显。南半球中等尺度的冷暖突变与年平均相对黑子数准11.2年的周期有着明显的对应关系。

关键词: 冷暖期, 层次结构, 气候突变