Arctic Sea Ice and the Mean Temperature of the Northern Hemisphere

• Main Authors: Laubereau, Alfred, Iglev, Hristo
• Format: Report
• Language: unknown
• Published: arXiv 2017
• Subjects: Geophysics physics.geo-ph; Atmospheric and Oceanic Physics physics.ao-ph; FOS Physical sciences; Arctic; albedo; Global warming; Sea ice
• Online Access: https://dx.doi.org/10.48550/arxiv.1706.05835; https://arxiv.org/abs/1706.05835

The importance of snow cover and ice extent in the Northern Hemisphere was recognized by various authors leading to a positive feedback of surface reflectivity on climate. In fact, the retreat of Arctic sea ice is accompanied by enhanced solar input in the Arctic region, i.e. a decrease of the terrestrial albedo. We have studied this effect for the past six decades and estimate the corresponding global warming in the northern hemisphere. A simple 1-dimensional model is used that includes the simultaneous increase of the greenhouse gases. Our results indicate that the latter directly cause a temperature rise of only 0.2 K in 1955 to 2015, while a notably larger effect 0.7 +/- 0.2 K is found for the loss of Arctic sea ice in the same time. These numbers comprise most of the reported mean temperature rise of 1.2 +/- 0.2 K of the northern hemisphere. The origin of the sea-ice retreat is discussed, e.g. internal variability or feedback by the CO2 concentration increase. Our data also suggest a delayed response of the global surface temperature rise to the loss of sea ice with a time constant of approximately 10 to 20 years. : 13 Pages, 2 figures