Recent letter writers have expressed conflicting opinions about sugar cane's carbon footprint. One writer said that cane burning gives off carbon dioxide, contributing to global warming. Another said that growing cane gives off oxygen, thus presumably helping. Neither view captures the big picture.
Growing then burning a plant is, in itself, carbon neutral. Growth pulls CO2 from the air, building plant structures from the carbon. Burning recombines that same carbon with oxygen, releasing CO2 back into the air. It is a cycle with no net change. Net CO2 release only comes from burning a fossil fuel whose carbon was stored underground for millions of years.
Complete cane burning includes not only the harvest burn but also final burning of the waste bagasse, firing the boilers and generating electricity. That electricity probably reduces Maui Electric Co.'s fossil fuel use by more than Hawaiian Commercial & Sugar Co.'s fossil fuel usage. Overall, the HC&S operation could be a net atmospheric carbon win.
But there are alternatives to field burning. HC&S could transition away from subsidized diabetes crystals and focus on renewable energy. It could grow something like sorghum that needs no field burning. Controlled burning in a modern incinerator does not give off smoke and soot (that white stuff coming out of the smokestack is steam). I expect that HC&S is looking at this and other alternatives.
Mitch Bradley
Makawao
