Measuring uplift and exhumation can be tricky. Measuring the uplift of a point requires measuring its elevation change – usually geoscientists are not trying to determine the uplift of a singular point, but rather the uplift over a specified area. Accordingly, the change in elevation of all points on the surface of that area must be measured, and the rate of erosion must be zero or minimal. Also, sequences of rocks deposited during that uplift must be preserved. Needless to say, in mountain ranges where elevations are far above sea level these criteria are not always easily met. Paleoclimatic restorations though can be very valuable; these studies involve inferring changes in climate in an area of interest from changes with time of flora/fauna that is known to be sensitive to temperature and rainfall. The magnitude of the exhumation a rock has been subjected to may be inferred from geobarometry (measuring previous pressure and temperature history of a rock or assemblage). Knowing the pressure and temperature history of a region can yield an estimate of the ambient geothermal gradient and bounds on the exhumation process; however, geobarometric/geothermometric studies do not produce a rate of exhumation (or any other information on time). One can infer exhumation rates from fission tracks and from radiometric ages as long as one has an estimated thermal profile.