Well the people who make a living projecting high CO2 levels would be surprised, since that is about 50% higher than their recent highest projections. Some olde

Well the people who make a living projecting high CO2 levels would be surprised, since that is about 50% higher than their recent highest projections. Some older predictions had the levels in 2100 up to 800ppm, but the IPCC has been revising them downward for quite some time now. This is in part because we've had them for long enough to see they haven't been accurate, and because the "worst case" ones don't use any theory they just calculated a straight based on the highest rate they find. These predictions have consistently been higher than actual data. So the likelihood that we'd hit 1000ppm by 2100 would mean they'd have to have predicted around 1100-1200 ppm by then, but their worst case is around 800ppm. Which, based on their historical performance would indicate the worst case is more akin to 600-700.