This is a complex question centering on the concept of drawdown. 

Presently, the oceans have sequestered many gigatons of human-produced carbon caused by burning fossil fuels. Some of this carbon reacts with water to form carbonic acid, turning the ocean’s PH from slightly alkaline to neutral or slightly acidic, killing corals and damaging shell-making ability of ocean-dwelling animals.  

The earth’s forests, including boreal forests in northern latitudes and rainforests near the equator, also have sequestered carbon for thousands of years. The destruction of these forests squanders this sink and releases the stored carbon back into the atmosphere. 

For drawdown to be effective, both these sinks must be restored.

Additionally, pasture and cropland, managed parts of the food system which feeds 8 billion people, can  sequester carbon.  The clearest way to think about this is to recognize that organic matter is 58% carbon. Cover crops, management intensive grazing, reduced tillage, and working with soil biology increase organic matter over time in a measurable way.