Credit: Nick Reddyhoff

By harvesting and burning fossil fuels, human beings essentially provide the tail end of a cycle hundreds of millions of years long. Plants and algae that grew by taking in carbon dioxide eventually turned into the deposits of coal and petroleum that we use to power our lives, rereleasing into the atmosphere the same carbon dioxide that nature had previously sequestered. Reducing these emissions will require us to change the way we think about both energy and carbon.

Select from the choices above to read the entire article.