What does this mean for fighting global warming? Brazil is the world’s eighth-largest emitter of greenhouse gases, and most of those emissions come not from industry and cars but from loggers, ranchers, and farmers burning the forest. Just substituting slash-and-char for slash-and-burn could reduce human-produced carbon emissions in the Amazon by 12 percent.
Even better, burning agricultural wastes in a controlled process called pyrolysis can convert wood and other organic waste into useful volatile gases, heat, electricity, and bio-oil. The process is win-win: Burning the biomass produces substantial amounts of rich biochar from waste material like peanut shells and rice husks, and mixing this biochar into soil could more than offset the carbon that is emitted into the atmosphere—not only during the burning process itself, but also when the derived fuels are used.
“You wouldn’t just be carbon neutral, you would be carbon negative, drawing carbon dioxide out of the atmosphere, producing energy and improving the climate in the process,” Lehmann says. Through workshops with other scientists, he is trying to spread the gospel about terra preta worldwide, carrying on where Petersen left off.
Samples of various Amazon soils showing the marked
color variation.
On August 13, 2006, on the anniversary of Petersen’s death, Neves
and the archaeologists at the Central Amazon Project held a daylong
commemoration, traveling from site to site in a large caravan,
describing each excavation and Petersen’s role in the work. Although he
helped revise the chronology of northeastern Native American and
Caribbean pre-Columbian archaeology, Petersen will perhaps be
remembered best for his work in the Amazon. He was not the first to
become enthralled with the puzzle of Amazonian prehistory, but he was
among the most passionate and effective in spreading his enthusiasm. He
never wanted to be the “one,” Heckenberger recalls, instead preferring
to give credit to the “many.” “He was a mentor to a lot of people, but
he never thought of it that way. He wasn’t teaching. He was sharing his
experience. It wasn’t a lecture, it was a dialogue. Jim was simply the
best archaeologist and the most infectious teacher I ever met.”
At the end of the day, the extended group gathers on the sandy beach at Açutuba. Before us lies the breathtaking expanse of the Rio Negro. Açutuba—the first and most extensive site excavated in the Central Amazon Project—is where this revolution in thinking about the Amazon began. Covering up to 75 acres, it had a central plazalike area surrounded by several mounds, established agricultural fields within a circumscribed radius, defensive earthworks, and palisades near the river.
From the beach you can look out at the broad Rio Negro and imagine what it must have been like for Spanish conquistadors exploring the river for the first time. Were these the spectacular settlements that Orellana described?
“I think the best homage we can pay to Jim is to continue the work,” Neves says, “to keep asking questions and to keep looking for answers.”
