WASHINGTON (AP) — For years, airlines have offered travelers concerned about climate change an option: For an additional fee, remove their share of carbon dioxide pollution from flight by paying to protect trees.
This is the idea behind forest carbon credits. Trees absorb carbon from the atmosphere. Forest carbon credits are promises that companies, individuals, and governments can buy to offset their emissions by paying to plant or maintain trees. Here’s a look at this type of carbon credit.
WHAT ARE FOREST CARBON OFFSETS?
Imagine a forest that is at risk of being cut down to make pasture for livestock or fields for crops. A broker arrives and promises to pay the forest owner—which might be a government—to prevent this from happening.
The land is officially designated as a carbon credit project. After that, trees should not be cut down or destroyed by fire. The developer sells these promises and keeps some of the money. Far away, a polluting company buys credits instead of reducing its own emissions by a certain percentage.
Trees store carbon in their tissues, which means the longer and healthier a tree grows, the more carbon it can store. Soil and vegetation also store carbon. When a tree is cut down, the carbon stored in it is usually released into the atmosphere. If trees are ground into large pieces of timber, some of the carbon remains stored.
HOW DO THEY WORK?
A forest carbon offset, like any carbon offset, is equal to one metric ton of carbon dioxide avoided, removed or absorbed. According to the U.S. Environmental Protection Agency, a typical passenger car emits about 5 metric tons of carbon dioxide per year.
Forest carbon offsets are a subset of the multibillion dollar carbon ‘offset’ market.
There are three main types of forest carbon offsets: loans that sequester carbon by replanting trees, loans that preserve trees at risk of felling, and others that promise to improve a forest’s management and increase carbon storage.
HOW DO TREES HOLD CARBON?
Trees absorb carbon through their leaves, which makes them crucial to maintaining a livable climate. Through photosynthesis, the process that converts sunlight into chemical energy in plants, they breathe oxygen as a byproduct. Carbon is permanently stored in a tree’s fibers until it dies and decomposes.
Deforestation accelerates climate change in several ways: It stops plants from photosynthesizing so trees no longer take up carbon. It is also often accompanied by burning, which releases a lot of carbon dioxide.
WHAT ARE SOME PROBLEMS WITH FOREST OFFSETS?
It’s the same problem that all types of carbon offsets face: Do they really work?
The forest carbon offset market has ballooned over the past decade as many policymakers see them as a way to combat climate change and even finance the transition to renewable energies. But environmental groups, scientists and other experts say offset programs can be misleading.
“The problem here is that most voluntary carbon markets are self-regulated,” said Arnaud Brohe, chief executive officer of climate consulting firm Agendi and carbon markets expert.
It is often difficult to assess the climate benefit of a loan. For a forest carbon credit to be viable, it must do something for the environment that would not otherwise happen; this is a very important concept known as ‘addibility’. Loans are only valid if these trees are at active risk of being cut down. Offsets are meaningless if the trees are already protected.
Another problem is seepage, where the preservation of one forest section leads to deforestation in the other. There are also sometimes double counting issues when the same loans are counted in two different ledgers. For example, with limited regulation, loans for trees protected in one location may be counted by that country plus the country or other entity that purchased the loans.
Experts say forest carbon offset sellers often exaggerate the benefits to the environment.
“Although the projects eventually end up conserving and preserving some land, the question is how much?” said Danny Cullenward, a California-based energy economist and attorney who studies carbon emissions.
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