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Regional Climate Sensitivity‐ and Historical‐Based Projections to 2100
Author(s) -
Hébert Raphaël,
Lovejoy Shaun
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl076649
Subject(s) - gcm transcription factors , climatology , forcing (mathematics) , climate change , environmental science , climate model , scale (ratio) , general circulation model , representative concentration pathways , projection (relational algebra) , climate sensitivity , sensitivity (control systems) , transient climate simulation , computer science , geography , geology , cartography , oceanography , algorithm , electronic engineering , engineering
Reliable climate projections at the regional scale are needed in order to evaluate climate change impacts and inform policy. We develop an alternative method for projections based on the transient climate sensitivity (TCS), which relies on a linear relationship between the forced temperature response and the strongly increasing anthropogenic forcing. The TCS is evaluated at the regional scale (5° by 5°), and projections are made accordingly to 2100 using the high and low Representative Concentration Pathways emission scenarios. We find that there are large spatial discrepancies between the regional TCS from 5 historical data sets and 32 global climate model (GCM) historical runs and furthermore that the global mean GCM TCS is about 15% too high. Given that the GCM Representative Concentration Pathway scenario runs are mostly linear with respect to their (inadequate) TCS, we conclude that historical methods of regional projection are better suited given that they are directly calibrated on the real world (historical) climate.