Original sentence: If the only variable considered is the emission of greenhouse gases related to human activity, then climate models predict that temperatures will increase in the future; however, the precise magnitude of these increases is still uncertain , with a range of +1.4°C to +5.8°C for the temperature change between 1990 and 2100 (note: this range also includes a slight cooling due to sulphate aerosols; for CO2 alone the numbers would be higher).Much of this uncertainty results from not knowing future CO2 emissions, but there is also uncertainty about the accuracy of climate models, chiefly in the areas of clouds and aerosols which have the potential significantly reduce the net effect of CO2, although the uncertainty is such that it is not known if they under- or overpredict future climate change.The paleo climate data, suggests that the predicted impact of CO2 should be lower than the models predict, although the paleo data reflects long term equilibria and cannot rule out higher temperature increases within the lifespans of humans living today
Edited sentence: Climate models predict that temperatures will increase (with a range of 1.4°C to 5.8°C for change between 1990 and 2100 []).Much of this uncertainty results from not knowing future CO2 emissions, but there is also uncertainty about the accuracy of climate models, especially the representation of clouds.The meteorological community has responded with skepticism, in part because theories of this nature have come and gone over the course of the 20th century