It seems that creating huge plane areas will induce tornadoes.

Hi Natalia.  Thanks.  In order to create tornadoes you need warm and cold air masses colliding.  I am not sure you would have that over Canada even today....

Not sure what you mean by "quickly". A typical test could be to simulate a time slice of the glaciation with and without an ice sheet. This is however quite expensive as you have to spin-down the ocean model to these conditions for >1000 years first. Located behind the Rockies in terms of westerlies, the position of the Laurentide ice dome might not as much influence the jetstream in addition.

You may have a look at the publication below (Löfverström et al., 2014) and many references therein for the influence of ice sheets on atmospheric circulation.

Article Evolution of the large-scale atmospheric circulation in resp...

Dear Joanne,

Prof. John E. Kutzback, of the University of Wisconsin in Madison, worked extensively on the climate impacts of large ice sheets over periods of tens of thousands of years. You'll be well advised to study his numerous publications. You can start by searching the Internet for his name.

Good luck. Michel.

Excellent advice. Thank you all very much.  Joanne :-)

I have looked at the effect of the Antarctic Ice Sheets, in particular on the effect to Ocean circulation.

https://www.researchgate.net/publication/224524073_Effects_of_mountains_and_ice_sheets_on_global_ocean_circulation

Journal of Climate (Impact Factor: 4.9). 06/2011; 24:2814-2829. DOI: 10.1175/2010JCLI3982.1

I hope this helps

Article Effects of Mountains and Ice Sheets on Global Ocean Circulation

Thanks Tiago.  I have also found a good study on Nature Geoscience discussed here: http://wattsupwiththat.com/2015/02/23/study-finds-massive-climate-change-in-north-america-before-there-was-even-an-argument-about-it/

Joanne, The articles cited above (various John Kutzbach publications; Schmittner et al 2011; and Oster et al 2015) are excellent suggestions. Another article that may be of interest to you, recently published in Climate Dynamics, is: doi:10.1007/s00382-015-2502-8; "Higher Laurentide and Greenland ice sheets strengthen the North Atlantic ocean circulation" by Xun Gong et al. 2015. Model simulations of various glacial and interglacial climates are conducted with the goal of identifying different [North Atlantic-based] surface-wind patterns (and associated ocean circulation patterns) that evolve under different profiles of ice-sheet topographies. Marcia

Oh nice, Marcia! Thanks for pointing this out.  Joanne :-)

If the Greenland ice sheet is removed the temperature contrasts between the warm air masses over North-Atlantic stream and cold air masses over Greenland will derease. That means weaker Iceland depression and decrease of the intensivity of western drift and more contunental climatic conditions in Europe.

I asked above - not sure what you mean by "quickly"?. There is a publication by Zhang et al. (2014) with a comprehensive complex fully coupled model about gradually changing the ice sheet height of the northern hemisphere. Based on the simulation for LGM conditions, this can trigger abrupt climate shifts resembling the DO-cycles. This is a very important result because so far most simulations only get rapid shifts through a meltwater pulse to trigger the AMOC. This simulation suggests it can happen without such a trigger just by ice sheet height changes.

Article Abrupt glacial climate shifts controlled by ice sheet changes

Hi Frederik, thanks for the recommendation. I will check into it. Have a great day, Greetings from Columbus Ohio, USA today.  Joanne :-)

Okay I see that it was Dmitry who answered. The RG display is a bit misleading. Thanks, Dmitry.

Frederic, I see that I did not answer your question. What I meant by "quickly" is the scenario where the Laurentide Ice Sheet was impacted by an extraterrestrial bolide, as proposed by Firestone et al. 2007.  I am studying dynamic environmental change from the Last Glacial Maximum to the Holocene and I am testing this hypothesis. The effects would have been large ice ejecta flung outwards, overland meltwater flow with scouring of soil and likely rock ala Channeled Scablands,, and, if a rim of LIS ice persisted, swash within the LIS basin of melwater possibly creating swarms of drumlins. 

Joanne,

One of the world authorities on climate change over long time periods, and in particular about the impact of ice sheets on the general circulation of the atmosphere, is Prof. John E. Kutzback. His home page is here

http://www.wicci.wisc.edu/kutzbach.php

and you'll find a comprehensive list of his publications here:

http://ccr.aos.wisc.edu/cgi-bin/htgrep.cgi?kutzbach&submit=Submit

Cheers, Michel.

Thanks very much Michel.  Greetings from Knoxville, Tennessee. :-)

Ah OK, I didn't know you're investigating a "scenario where the Laurentide Ice Sheet was impacted by an extraterrestrial bolide" (around 12.9 kyr BP). I'm not sure if this event really took place but it is a very good idea to test it. The Younger Dryas cooling in the model is simply simulated by fresh water slowing down the AMOC. It is however not clear where and how much really entered the ocean. The melt water was more or less tuned to get the simulation in line with proxy evidence. Would be nice if you can keep me up to date if you've found out more.