In conventional δO analysis, both the δO values in carbonates and water are needed to estimate paleoclimate. However, for many times and places, the δO in water can only be inferred, and also the O/O ratio between carbonate and water may vary with the change in temperature. Therefore, the accuracy of the thermometer may be compromised.
Whereas for the carbonate clumped-isotope thermometer, the equilibrium is independent of the isotope compositions of waters from which carbonates grew. Therefore, the only information needed is the abundance of bonds between rare, heavy isotopes within the carbonate mineral.