The Earth System Science Education Alliance (ESSEA)is administered by the Institute for Global Environmental Strategies through a grant from the National Science Foundation. More than 40 universities are members of ESSEA and offer courses in Earth system science for teachers using ESSEA developed materials. ESSEA courses are problem-based, modular, and incorporate group learning. Each module is designed to take three weeks in a normal university semester. Over 20 modules are currently available, so courses can be built around a class's particular needs. A similar number of modules are under development or review. Stratospheric ozone, coral reefs and El Nino are among the modules available. Each module is divided into three cycles with four assignments to be completed for each module. Individual assignments include examining prior knowledge and developing a lesson plan, while group assignments include researching the topic and developing an Earth system science analysis. Each module is designed to show how events do not occur in isolation and consists of three cycles. In the first cycle, a teacher will begin by reading a scenario and then explore his or her own beliefs of what is happening in the Earth system, sharing these ideas with teammates. In cycle two, the teachers investigate the issue and build a knowledge base. In cycle three, the teachers build their own lesson plan based upon what they have learned. In the past year, two Earth system science courses for in-service teachers have been offered by Seattle Pacific University. Sixteen teachers have completed a course for either three or five graduate academic credits (quarter credits).In our first course, in addition to an introductory module that introduces the concepts of Earth system science analysis and problem-based learning (PBL), modules that were completed included Global Climate Change; Brazilian deforestation; Mount Pinatubo; and Earth system science data and analysis. Nearly 20 additional modules are under development.We had some attrition for our first course. Of 11 teachers who initially enrolled, eight completed the course. The main issue for those who did not complete the course appeared to be with the Internet technology. The program is funded through October, 2009.