Exascale supercomputers are a disruptive technology because of their complex memory hierarchies and increasing distance between memory and disk.  Efficiently using an exascale machine also requires ultra-high resolution.  Such simulations produce a unique challenge for the model input and output due to the scale of the simulations, the amount of data being read and written out and the unique machine architectures. The SCORPIO (Software for Caching Output and Reads for Parallel I/O) library used by E3SM is able to meet these challenges. In this poster we will discuss how the SCORPIO library is able to achieve good I/O performance for decadal-scale SCREAM simulations. We will present our latest results of simulations from exascale supercomputers like Frontier and will also present the recent advances in the SCORPIO library that facilitate debugging and tuning of I/O for exascale E3SM simulations.