First, make a copy of the XML file in Rhye's and Fall, so you can put it back if this does not work or if you want to have Global Warming work again. Be sure and label it so you know where it came from. Then
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So, find the XML in Rhye's and Fall and make the above change. If Rhye's and Fall has already modded Global Warming in some way, this may or may not work.
Oh yeah, one more detail. You can't "change horses in mid stream". In other words, no modding change will affect a game already in progress. You have to make the change before starting a game. This is because all these status things are part of the Savegame.