Paper: Loptson et al 2014

Title: Investigating vegetation–climate feedbacks during the early Eocene

For a fuller description of the paper itself, go to the end of this web page.

Each simulation published in this paper corresponds to a unique 5 or 6 character code on the web pages.
The following table lists the name of the simulation as used in the paper, and the corresponding code name

The webpage gives you the ability to examine the published simulations, but you can also download the raw (netcdf) files to perform your own analysis. Detailed instructions on how to use the webpages and access the data can be found here: Using_BRIDGE_webpages.pdf

There are 6 simulations used in this paper: 3 different ice sheet states on 2 different palaeogeographies at the EOT

You can have make you own analysis and plots by going here

Simulation Name as in PaperSimulation name on web pages
2xSHRUBtddmz
4xSHRUBtddmg
2xDYNtddmr
4xDYNtddms
4xFIXEDtdghu


This is a fuller description of paper

This paper shows that including vegetation feedbacks in HadCM3L by including TRIFFID in the model does warm the climate at high latitudes in the early Eocene, but not enough to explain the model-data discrepancy.

NameLoptson et al
Brief DescriptionThis paper shows that including vegetation feedbacks in HadCM3L by including TRIFFID in the model does warm the climate at high latitudes in the early Eocene, but not enough to explain the model-data discrepancy.
Full Author ListClaire A. Loptson, Daniel J. Lunt, Jane E. Francis
TitleInvestigating vegetation–climate feedbacks during the early Eocene
Year2014
JournalClimate of the Past
Volume10
Issue3-4
Pages419-436
DOI10.5194/cp-10-419-2014
Contact's NameClaire Loptson
Contact's emailC.Loptson@my.bristol.ac.uk
AbstractEvidence suggests that the early Eocene was a time of extreme global warmth. However, there are discrepancies between the results of many previous modelling studies and the proxy data at high latitudes, with models struggling to simulate the shallow temperature gradients of this time period to the same extent as the proxies indicate. Vegetation–climate feedbacks play an important role in the present day, but are often neglected in these palaeoclimate modelling studies, and this may be a contributing factor to resolving the model–data discrepancy. Here we investigate these vegetation–climate feedbacks by carrying out simulations of the early Eocene climate at 2 × and 4 × pre-industrial atmospheric CO2 with fixed vegetation (homogeneous shrubs everywhere) and dynamic vegetation. The results show that the simulations with dynamic vegetation are warmer in the global annual mean than the simulations with fixed shrubs by 0.9 ◦C at 2 × and 1.8 ◦C at 4×. Consequently, the warming when CO2 is doubled from 2 × to 4 × is 1 ◦C higher (in the global annual mean) with dynamic vegetation than with fixed shrubs. This corresponds to an increase in climate sensitivity of 26 %. This difference in warming is enhanced at high latitudes, with temperatures increasing by over 50 % in some regions of Antarctica. In the Arctic, ice–albedo feedbacks are responsible for the majority of this warming. On a global scale, energy balance analysis shows that the enhanced warming with dynamic vegetation is mainly associated with an increase in atmospheric water vapour but changes in clouds also contribute to the temperature increase. It is likely that changes in surface albedo due to changes in vegetation cover resulted in an initial warming which triggered these water vapour feedbacks. In conclusion, dynamic vegetation goes some way to resolving the discrepancy, but our modelled temperatures cannot reach the same warmth as the data suggest in the Arctic. This suggests that there are additional mechanisms, not included in this modelling framework, behind the polar warmth or that the proxies have been misinterpreted.