Forests have long been dubbed as "the lungs of the Earth." Their carbon storing capacity has attracted green investments from companies and governments looking to reduce their carbon footprint by restoring and preserving forestry landscapes. A recent study by Yale University, however, revealed a culprit, right in the back yard of most forests, which is likely to alter the way emission reductions in some forestry offset projects are being accounted for.
Yale researchers studied samples collected by the United States Geological Survey from over 4,000 U.S. streams and rivers. Their findings were unexpected, to say the least.
"Rivers and streams in the United States are releasing enough carbon into the atmosphere to fuel 3.4 million car trips to the moon," states the report published on the website of the Yale School of Forestry and Environmental Studies. The amount is estimated to be around 100 million metric tons of carbon dioxide each year - the equivalent of a car burning 40 billion gallons of gasoline.
But where is this staggering magnitude of carbon release coming from? And, more importantly, how does it translate when it comes to the future of green investments in forestry offsets?
There are three main causes for carbon leakage into rivers and streams: decomposition of dead trees and other plants, changes in atmospheric conditions and human activity.
"A significant amount of carbon contained in land, which first is absorbed by plants and forests through the air, is leaking into streams and rivers and then released into the atmosphere before reaching coastal waterways," scientists explain.
Their paper also notes that climate changes cause more precipitation, which in turn will cause more terrestrial carbon leaking into streams and rivers. And what researchers are further trying to determine is how much of the carbon release is caused by human activities, such as logging and land development.
The Yale study, which was partly funded by a NASA Earth and Space Science Fellowship and a NASA Carbon and Ecosystems Program grant, will no doubt change the way forestry carbon budgets are being calculated.
Many green investments focus on reforestation and conservation of trees as a way to offset emissions done by human and industrial activities in other geographic areas. Some of these offsets are eligible for carbon credits, which they sell as a way to earn revenue and sustain themselves financially. Carbon credits are issued on the basis of how many tons of greenhouse gas emissions are being sequestered by the forest each year. The above study findings may lower the carbon sequestration value of forests along rivers and streams, posing not only financial, but also managerial challenges.
For one thing, a forest situated next to a carbon-spewing river or stream will end up with a lower overall carbon reduction capacity. This, in turn, will lead to less carbon credits issued and lower revenue for investors. Most effected of these changes are likely to be offset projects in the Amazon and other tropical areas. The sustainability of local communities will also be impacted as many poor indigenous people from these communities rely on revenue from carbon credit sales as a source of income.
The added carbon breathing capacity of rivers will also prompt changes in some carbon standards. Third-party quality assurance entities may have to revise their offset evaluation process and adapt their reduction quantification methods to reflect the new carbon balance of forests situated along river basins.
The role of human activity in carbon leakage into streams and rivers is another challenge, which, although yet to be specified, can have a significant impact on how forestry offsets are managed. If logging and other land developments, such as tourism and agroforestry, prove to be significant contributors to carbon release into the water of streams, offsets will have to employ new methods aimed at curbing harmful human activity in those forestry areas.
