Current projections indicate that the partial pressure of CO2 in earth's atmosphere will be double the level of the preindustrial era somewhere between the years 2036 and 2060 resulting in a 20C - 30C increase in global temperature. There is a large uncertainty concerning the quantitative ability of the oceans to absorb anthropogenic CO2 and the influence the uptake will have on global climate. A small, low power, low cost, analytical instrument is proposed with the sensitivity, durability, and long term stability to make continuous measurements of the CO2 concentration above and below the oceanic surface for periods of one year or longer without calibration or repair. During Phase I, prototype CO2 sensors were fabricated and tested with the capability of responding to 100 x 10-12g of CO2. In laboratory tests, the prototype sensor was able to measure CO2 levels to 100 ppm in the presence of oxygen and nitrogen gases. Power consumption was measured at 250 uW per sensor. During Phase II, high performance sensors will be incorporated into a prototype CO2 monitoring instrument system suitable for deployment with existing ocean monitoring and telemetry systems. Performance of the prototype will be quantified in the laboratory and ocean environment.