I think that calculating the true cost of any new regulations with any certainty, let alone the sweeping changes being proposed, is not really possible. Common sense tells me it will cost a lot in both hard dollars and productivity.
But it's even more ethereal to predict the impact of these regulations on climate. We don't even know that a warmer climate is even a bad thing on the whole - there are studies to the contrary - let alone whether such regulations would have any impact whatsoever. Common sense tells me it would have little to no impact.
But I don't need to rely on just common sense. Somebody posted somewhere that all the models predicted significant global warming over the last 20 years, and all these models were wrong. Despite pumping greater and greater amounts of CO2 into the atmosphere, warming has stalled. Hurricanes and other severe weather are at near record lulls. Our planet doesn't really seem to give two shits about what we do. Life goes on.