Isotopic analysis of carbon dioxide is an important tool for characterization of the exchange and transformation of carbon between the biosphere and the atmosphere. These measurements require highly accurate and precise instruments that are capable of providing isotopic abundances to discriminate between man-made and natural carbon sources. Laser-based isotopic measurements offer the Earth Science research community an opportunity to gather critical information on the generation and fate of carbon dioxide. Improvements to existing technology are needed for carbon isotope measurements to be made with minimal labor, for long periods, in remote areas and harsh conditions. The proposed Phase I project extends the application of well established near infrared laser and detector technology that is proven in trace gas field measurements towards the development of an automated isotopic carbon dioxide sensor that can be deployed in balloon-based systems, remotely operated robotic aircraft, or in harsh conditions such as volcanic fumaroles.