Getting Back to the Garden

摘要

Growing levels of anthropogenic carbon dioxide (CO2) emissions and related global warming are challenging the world to find new sources of energy that do not contribute to the increase in atmospheric greenhouse gases. Ideally, such sources would be renewable and sustainable, which implies that they should not be based on fossil fuels. In principle, biomass can meet these requirements, and thus is gaining popularity as a fuel source. It is sometimes considered to be carbon neutral, because the carbon emitted as CO2 during combustion came from the atmosphere by way of photosynthesis, but that calculation should take into account a complete cycle, which means that biomass equal to the amount harvested must be regrown.