Would Obama's climate swindle take tens of millions of farmland out of production?

Johanns takes on climate bill

[Sen. Mike Johanns, R-Neb] then wanted to know if cap and trade passes and money is to be made from planting trees, how much farmland will be lost?
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Johanns pressed further. “I’m not asking you about productivity. I’m asking you — or maybe (Jackson) — to tell me in your forecasts how many productive acres of farmland will go out of production. We’ll start there. Then, I’ll ask other questions.”

Jackson, too, claimed not to have such a number. “I have heard numbers that are being attributed to EPA’s modeling efforts that are on the order of tens of millions of acres. We’re looking into that. But what EPA’s models show and the conclusion you can draw is that if an offset is geared around aforestation, many farmers will choose to do that. But we don’t have a firm estimate.”
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[Johanns] “And yet we have a House bill (Waxman/Markey) that passed. I find that shocking. I find it amazingly shocking that could happen without the aforementioned information being available.”

From a letter to Peterson here:

There are a number of different analyses on cap and trade that show reductions in farm income reaching all the way up to 94 percent by 2035. And, according to press reports, EPA is projecting that this legislation would take 56 million crop acres out of production due to afforestation. For these reasons, we must continue to gather information on the consequences of this legislation.