A technique known as "enhanced rock weathering" may help remove carbon from the atmosphere, and a model shows the method will only leak minimal carbon if its products are stored in the ocean. Constraining the planet below 1.5ºC or 2ºC of global warming from a preindustrial baseline by century's end will be more likely if carbon dioxide currently in the atmosphere is physically removed. Many climate models include the removal of between 5 and 10 gigatons of carbon dioxide per year through the end of the century.