In the upcoming years, high-resolution, long-duration simulations performed with advanced climate models will produce tens of petabytes of output. To be useful, this output must be made available to global change impacts researchers nationwide, both at national laboratories and at universities, other research laboratories, and other institutions. The magnitude and complexity of the data problem already challenges the strained resources of research groups and has the potential to stand as a formidable barrier to research progress if not addressed. For target research goals to be realized, fundamentally new methodologies for managing, accessing, recombining, analyzing and intercomparing distributed data are required. The Earth System Grid (ESG) is a DOE-sponsored research effort aimed at addressing this problem by building a foundation for next-generation analysis applications, web-based data portals, and collaborative problem-solving environments. Collaborators from DOE centers, USC, and NCAR have built upon the Globus toolkit, Data Grid technologies, and high-bandwidth networking to develop techniques and technologies for high-speed movement of data between centers and users, replica catalogs for keeping track of data location, request managers for coordinating multiple transfers, and a Grid-enabled version of the data analysis package produced by the Program for Climate Model Diagnosis and Intercomparison (PCMDI). Future efforts will include the development of distributed processing capabilities with an emphasis on server-side support for analysis, integration with thin-client data portal environments, and experimentation with the blending of emerging community infrastructure such as DODS (the Distributed Oceanographic Data System) and LAS (PMEL’s Live Access Server). Though the current focus is climate research, ESG technology potentially has broad applicability to other earth system research such as weather and beyond to any project that relies upon large-scale distributed computing and subsequent data analysis by a geographically dispersed community.