Convert from megagram to gigatonne

Unit Definition (megagram)
The megagram is an SI unit of mass equal to one million grams or 1000 kg. This means the megagram is identical to the tonne (metric ton). Large masses are almost always stated in tonnes in commercial applications, but megagrams are often used in scientific contexts. One megagram equals about 2204.623 pounds.

Unit Definition (gigatonne)
The gigatonne is a metric unit of mass or weight equal to one billion metric tons (tonnes) or about 2.2046 trillion pounds. This very large unit is used, for example, in discussing the amounts of carbon added to the atmosphere by human activities.