Climate change will impact health through a variety of pathways - both direct and indirect. Identifying the specific link between climate-related hazards and vulnerability will require the integration of socio-environmental, meteorological, and health data. An enhanced monitoring and tracking system is critical for public health efforts to identify and reach populations vulnerable to climate-related hazards, mobilize resources, and inform local climate action policy to reduce climate-related health risks. In this paper we present a novel application of a geospatial tool that integrates multiple data sources, allowing for the streamlined visualization of environmental risk, socio-economic and demographic vulnerability, baseline mortality, and policy intervention measures. GEMSS (Geospatial Emergency Management Support System) is a browser-based application that is designed to assemble geospatial information from multiple local or remote sources in a common operating environment, allowing for multi-data visualization. Using vulnerability to extreme heat and heavy rainfall-induced flooding as climate impacts on health, we tested GEMSS's capability as a multi-data platform to visually analyze spatial patterns of climate change environmental public health indicators at the local level. The selected indicators relied on socio-environmental and demographic vulnerability, health, policy, and weather data. The GEMSS system has the potential to support multiple goals including: a) the ongoing monitoring and assessment of climate-related vulnerability through visualization; b) providing policymakers with an open-source tool for understanding how vulnerable populations and the environment could be impacted by proposed climate action policies; c) tracking the ongoing status of climate change policies in reducing socio-environmental vulnerability; d) raising awareness among the general public about the links between climate change and public health; and, e) providing a basis for epidemiologic research (i.e., identifying gaps between climate and human vulnerability leading to hypotheses and hypotheses-testing). (C) 2011 Elsevier Ltd. All rights reserved.