Carbon dioxide of fossil fuels and deforestation have caused the atmospheric concentration of carbon dioxide to increase by about 43% since the beginning of the age of industrialization. Most carbon dioxide from human activities is released from burning coal and other fossil fuels. Other human activities, including deforestation, biomass burning, and cement production also produce carbon dioxide. Human activities emit about 29 billion tons of carbon dioxide per year, while volcanoes emit between 0.2 and 0.3 billion tons. Human activities have caused to increase above levels not seen in hundreds of thousands of years. Currently, about half of the carbon dioxide released
Ocean storage of carbon dioxide IEA Greenhouse Gas R&D Programme estimates that dilute carbon dioxide injection would cost $70 per tonne of carbon dioxide including costs of carbon capture, transport, and storage before boat dispersal. Carbon dioxide ocean storage can occur through solid or solid hydrate of carbon dioxide. The solid state density of carbon dioxide is approximately 1.5 times greater than seawater and thus tends to sink to the ocean floor. The dissolving rate at the surface is about 0.2 cm/hr such that a small quantity of carbon dioxide can be completely dissolved before reaching the sea floor. In addition to solid carbon dioxide