The phenomenon of global warming is anincrease in the earth's temperature due to thegreenhouseeffect where 50% of the main contributors to thegreenhouse effect are carbon dioxide (CO2). Carbondioxide is one of the ingredients needed for photosynthesis.Photosynthesis is carried out by plants that havechloroplasts. Plants in the watersare Seaweed. Gracilariachangii is a type of red seaweed (Rhodophyceae). Thedominant pigment from Gracilaria changii is carotenoids.Carotenoid serves as a light energy absorbent forphotosynthesis and serves to protect chlorophyll from lightdamage. Seeing the important role of carotenoids inGracilaria changii so that this study aims to determine theeffect of increasing temperature and carbon dioxideoncarotenoid pigments.Research on the scenario of globalwarming in this region was first carried outon alaboratory scale, many previous studies were carried outin the cultivation area.Thisstudy was conducted for 40days, seaweed that has been cleaned is put into anaquarium and given an injection of CO2. We were exposedto present-day control seawater (400 ppm pCO2) andseawater treated with CO2to simulate ocean conditionspredicted for the next 50–100 years (700 ppm, 1000 ppm,and 1300 ppm) and temperature treatment (30oC, 32oC,34oC). The research design applied in this study is aCompletelyRandomized Design consisting of ninetreatments with three replications. Data analysis used isAnalysis of Variance (ANOVA) continued by Post hocTest. The results obtained from this study there weresignificant differences (P <0.05) of carbon treatment incarotenoid pigments. The highest carotenoid pigments arefound in 700 ppm CO2injection treatment.