>Climate modeling, like most compute intensive fields, uses Fortran because it's fast and that's what the software needs to be. Also because the laws of physic

>Climate modeling, like most compute intensive fields, uses Fortran because it's fast and that's what the software needs to be. Also because the laws of physics (and the math to do approximation) don't change very often. The older that Runge-Kutta function is in the codebase, the more chance it has to be part of the sample code that they test the compiler's optimizer/benchmark with too! And Fortran is old enough it's possible to build wrappers around it, should the user really need a new interface.