Oslo Pilots CCS System at Waste Incineration Plant to Slow Climate Change

by Erin Larsen

Norway just became the first country to attempt to capture CO2 from the fumes of burning trash. A test plant at a waste incinerator in Klemetsrud will test several technologies for CO2 capture with a goal of presenting results to the government by June 2016. If successful, this innovative project will be a huge step forward for carbon capture technology and will help Norway mitigate the environmentally degrading impacts of its largest emission source. Continue reading

Coffee Agroforests Can Store Significant Levels of Carbon

by Stephen Johnson

Over 40% of the world’s terrestrial surface is covered by agricultural activities, and approximately half of that area is agroforestry. Agroforests, agricultural areas that are at least 10% covered by tree shade, run the gamut from areas with a few exotic species to structurally complex, highly diverse ecosystems that mimic natural forests. Woody vegetation biomass is approximately 50% carbon, so incorporating trees into agricultural areas significantly improves the ability of these systems to sequester and store carbon. Given that agroforests cover almost half a billion hectares, they may represent a significant and underestimated carbon sink. The amount of carbon that can be stored is determined by a variety of factors, including the number of trees and the density of their wood. The type of and number of the trees present in turn depends on the individual management of the farm. In Ethiopia, Tadesse et al. (2014) investigated how different management regimes affected the species of trees present and the amount of carbon stored, compared to natural forests. They measured the density and species of trees in smallholder coffee farms, state-owned plantations, and forest fragments, and used these measurements to determine the carbon storage capacity of each forest. They also interviewed farmers to see how and why species are selected for inclusion in plantations. Tadesse et al. found that agroforests can store 50-62% of the carbon that natural forests can store. They also found that farmers tended to prefer and harvest denser-wooded species, though less dense species were used for some limited purposes. Continue reading

Carbon Storage in Restored Forests is Species and Age Dependent

by Stephen Johnson

Deforestation in tropical rainforests is a significant and growing conservation concern, and for good reason: as well as harboring high levels of biodiversity, tropical forests are estimated to store 59% of global terrestrial carbon. The capacity of woody plants to store carbon, which constitutes 50% of their biomass, makes them an indispensible consideration in the effort to mitigate global climate change. Of course, forests can’t store carbon if they don’t exist. In the past 14 years alone, more than 100 million hectares of tropical forest have been lost—an area greater than Texas and Arizona combined. This continued destruction has prompted interest in the ability of ecological restoration—replanting forests—to provide ecosystem services such as carbon sequestration and biodiversity habitat. In attempting to rapidly revitalize damaged ecosystems, fast-growing, pioneer species with low wood density are often chosen to replant, though slower-growing, denser species may be required for long-term carbon storage and ecosystem health. To help resolve this question, Shimamoto et al. (2014) examined the biomass accumulation of ten tree species with different ages and growth patterns. By comparing measurements of fast and slow-growing trees in forests of different ages, they were able to determine carbon sequestration through analysis of covariance tests as well as linear and non-linear models. They found that in the first 35-40 years, fast-growing species accumulate the most carbon, but after 40 years, slow-growing species accumulate more carbon, and older forests overall sequester more carbon than young forests. Continue reading

Underground Storage of CO2 : Attempts to Eliminate Carbon Emissions

by Nour Bundogji

Postdoctoral researcher Yossi Cohen and Professor of Geophysics Daniel Rothman, at Massachusetts Institute of Technology, recently published an article in the Royal Society Proceedings on the effectiveness of storing carbon dioxide underground in an effort to decrease carbon emissions in our atmosphere. When I first read this I immediately envisioned suction cups elevated high into earth’s atmosphere connected to long pipes extended deep within earth’s crust. Yet, you guessed it, the technology is quite different. Instead, greenhouse gases emitted by coal-fired power plants would be pumped into salt caverns 7,000 feet underground where these gases would react with the salt water and solidify (Cohen and Rothman, 2015). The U.S. Environmental Protection agency estimated that this technology could eliminate up to 90 percent of carbon emissions from coal-fired facilities. Considering the current state of our ozone layer and the drastic climate changes we’ve been experiencing these past years, this seems like a promising step forward in saving our environment. However, commentators on this technology, like Christopher Martin from Bloomberg, pointed out a few flaws. I knew it was too good to be true. Continue reading