Carbon dating unreliable
Isochron methods avoid the problems which can potentially result from both of the above assumptions.
Isochron dating requires a fourth measurement to be taken, which is the amount of a different isotope of the same element as the daughter product of radioactive decay.
This is clearly a very complex task, so models are built to estimate are weather, averaged out over time - usually 30 years.
Trends are important because they eliminate - or "smooth out" - single events that may be extreme, but quite rare.
The simplest form of isotopic age computation involves substituting three measurements into an equation of four variables, and solving for the fourth.
The equation is the one which describes radioactive decay: If one of these assumptions has been violated, the simple computation above yields an incorrect age.
In addition, it requires that these measurements be taken from several different objects which all formed at the same time from a common pool of materials.
The models successfully predicted the climatic response after the eruption.
Models also correctly predicted other effects subsequently confirmed by observation, including greater warming in the Arctic and over land, greater warming at night, and stratospheric cooling.
However, all models improve over time, and with increasing sources of real-world information such as satellites, the output of climate models can be constantly refined to increase their power and usefulness.
Climate models have already predicted many of the phenomena for which we now have empirical evidence.