Climate Change Part 1: Arctic and Antarctic – Lecture 11 PDF

Arctic and Antarctic climate change  Feedbacks System generates outputs that influence its operation Positive feedbacks generate change in the system Negative feedbacks dissipate Ruddiman 2014  The relationships...

Arctic and Antarctic climate change  Feedbacks System generates outputs that influence its operation Positive feedbacks generate change in the system Negative feedbacks dissipate Ruddiman 2014  The relationships between variables are important for understanding how feedbacks work Direct relation (+) Inverse relation (-) Variable 2 Variable 2 Variable 1 Variable 1 Direct (positive) relation – an increase in variable 1 = an increase in variable 2 Inverse (negative) relation – an increase in variable 1 = a decrease in variable 2  Positive feedback response continues to be amplified + Air temperature - Atmospheric greenhouse Permafrost gas concentrations + - Methane emissions  Negative feedback original disturbance is diminished - Air temperature + Sunlight reflected Evaporation + + Low clouds  Carbon dioxide in the atmosphere The Keeling Curve International Geophysical Year (1958)  The instrumental record Warmer than the period 1951-1980 Colder than the period 1951-1980 The Arctic is warming faster than anywhere else on Earth  Arctic amplification Excessive warming in the Arctic compared to the rest of the globe  Arctic amplification Ratio of Arctic warming to global mean warming Any change in the net radiation balance tends to produce a larger change in temperature near the poles compared to the planetary average Earth’s warming 0.85°-1.1°C Arctic warming up to 4x faster Rantanen et al. 2022 Nature, Communications Earth & Environment Arctic amplification  Why does the Arctic warm faster? Multiple factors proposed, including – Enhanced ocean heating and ice-albedo feedback – Ocean heat transport to Arctic Ocean – Meridional atmospheric moisture transport to Arctic  Arctic sea ice The new abnormal