Global Warming, Atlantic Multi-decadal Oscillation, Thermohaline Catastrophe and Their Impact on Climate of the North Atlantic Region

摘要

This paper presents investigation of regional and global warming, Atlantic Multidecadal Oscillation (quasiperiodic natural variations of the ocean-atmosphere system in the North Atlantic with typical time scales of 50-100 years) and thermohaline catastrophe (blocking of thermohaline circulation in the North Atlantic). The typical scale of the Atlantic Multidecadal Oscillation (AMO) is determined by the intensity of the meridional oceanic circulation in the North Atlantic. The analyzed oscillation affects various climatic characteristics: air temperature, river discharge in the European and North-American regions, the number and intensity of tropical cyclones in the Atlantic Ocean, and the parameters of mid-latitude cyclones and anticyclones in the Atlantic-European region. The main mechanism by which the AMO affects the climatic characteristics of the regions neighboring with the North Atlantic is the atmospheric response to the thermal anomalies in the ocean leading to a shift of the centers of atmospheric action and to the changes in the intensity and predominant directions of propagation of atmospheric cyclones and anticyclones. By using the results of long-term instrumental observations carried out in Eastern Europe and the data array of reconstructed temperature in the Alpine region, it is shown that the AMO is responsible for a significant part of low-frequency variations of temperature in Europe. This fact confirms the potential predictability of the regional atmospheric AMO on the decadal-scale. The rate of quasi-periodical regional warming/cooling of surface air temperature due to AMO can exceed the regional temperature rising due to global warming. So, the fast warming of the North Atlantic region during the last 3-4 decades of the twentieth century is due to coincidence of human-induced temperature increase and transition from negative to positive phase of the AMO. Realization of thermohaline catastrophe for the recent climatic epoch is unlikely.