The people who lived in the Amazon regions back before any Europeans showed up on the scene had an ingenious way to survive there. By creating mounds of biochar, the pre-Columbian peoples made beds for their crops that drained far better than the native soil, which is nutrient-poor and prone to flooding. And, it seems, they unintentionally contributed to the biodiversity of the region.
In a study in the Proceedings of the National Academy of Sciences, scientists led by Doyle McKey of France investigated the savannas of French Guiana, in the far northern part of South America. These plains are flooded during the rainy season, dry and parched in the summer, and often burned by fires. It was while walking through this landscape that McKey started wondering about undulations in the terrain [New Scientist]. Just how effective were these people at creating favorable cropland? McKey found that the drainage capacity of the mounds was nine times that of the rest of the savanna.
The Republic of Maldives has big plans for discarded coconut shells: they can become both a fertilizer and a planet-cooler. The Maldivian government has announced plans to burn the shells and turn them into biochar, a form of high-carbon charcoal that takes a long time to decompose, and which can be used to nourish the soil. It’s one effort of many that the government of the Indian Ocean archipelago hopes will help it achieve carbon neutrality by the year 2020.
The “slow-cooked” organic waste project was launched through a partnership between the Maldives government and the British company Carbon Gold. The scheme would not only reduce organic garbage, it would also decrease dependence on imported fertilizer. Carbon Gold argues that the biochar is an effective way of removing CO2 from the atmosphere. The company says the fertiliser also improves soil fertility…. “Waste that would have rotted or been burnt before is now locked up and put very safely in the soil,” [BBC], says company cofounder Daniel Morrel. Researchers believe that biochar doesn’t break down (and therefore release its carbon) for hundreds of years.
A climate scientist in England has invented a new process for turning wood into charcoal with giant microwaves, and says that the technique may be the best tool humans have for sequestering carbon and slowing global warming. The “biochar” created in the process locks in carbon from the wood, and sequesters it for thousands of years before the charcoal finally decomposes.
Biochar received new attention recently when researchers ranked geoengineering schemes based on their ability to slow global warming, and listed biochar as one of the most effective (and cheapest) approaches. The English scientist, Chris Turney, is eager to move from theory to practice, and has founded a company called Carbonscape that set up a microwave-powered kiln in Blenheim, in New Zealand’s South Island, in October last year…. The stove the Carbonscape directors call the Black Phantom can fix up to one tonne of carbon a day [The Australian].
Charcoal is typically produced by slowly heating wood in industrial ovens, but Turney says his microwave process is cleaner and more efficient. The idea came from a cooking accident when he was a teenager, in which he mistakenly microwaved a potato for 40 minutes and found that the vegetable had turned into charcoal. “Years later when we were talking about carbon sequestration I thought maybe charcoal was the way to go,” he said [The Guardian].
Sunshades in the stratosphere to reflect sunlight away from our planet. Dumping iron into the oceans to encourage algae blooms that would take up carbon dioxide. Painting every rooftop white. These are just a few of the geoengineering schemes that have been suggested to artificially alter the planet’s climate and counteract global warming.
Now researchers have helpfully ranked 17 proposals on their possible efficacy, saying that it’s past time to take a hard look at the ambitious ideas. “There is a worrying feeling that we’re not going to get our act together fast enough,” says [coauthor Tim] Lenton, referring to international efforts to limit greenhouse gas emissions. Scientists have reached a “social tipping point” and are starting to wonder which techniques might complement emissions cuts, he says [New Scientist]. The study, published in Atmospheric Chemistry and Physics, didn’t include an analysis of costs and environmental impacts.
Lenton says there has been too much hype and not enough analysis regarding geoengineering schemes, so he decided to start by asking a straightforward question. At the most basic level, earth’s surface temperature is governed by a balance between incoming Solar radiation and outgoing terrestrial radiation [Physics World]. The researchers examined how each of the geoengineering schemes would sway that balance, either by reflecting away solar radiation or reducing carbon dioxide that traps heat in the atmosphere. They found that a few proposed technologies could have a planet-wide cooling impact, but say those would be extremely hard to pull off.