Evidence for the Leading Role of Temperature Variations Relative to Greenhouse Gas Concentration Variations in the Vostok Ice Core Record

摘要

The cause-and-effect interrelation between long-term variations in temperature and greenhouse gas concentration (GGC) in the atmosphere is an important aspect of the problem of climatic variations. According to [1], anthropogenic GGC growth is of primary significance, whereas recent warming is a consequence of the GGC-induced greenhouse effect [1]. However, the available paleoclimatic data cast doubt on the unconditional unidirectional character of this interrelation. It has been established that the onset of the four glacial epochs was characterized by synchronous (coherent) decreases of the air temperature (based on the deuterium content dD in the Vostok ice core) and the methane (M) concentration, while the carbon dioxide (C) concentration decreased with a small lag [2]. The onset of the interglacial warm epoch was probably triggered by insolation growth. The increase of GGC (particularly, M) was at first slow and then significantly rapid. According to [3], the C growth lag was 600 ± 200 yr, which is within the relative accuracy range of time scales for the compared series (approximately ± 1000 yr), because air bubbles, which are used for the GGC assessment, diffuse within the ice core for several thousands of years after snow deposition.