Americans love easy answers. When we don’t know what the real impact of our lifestyle is on the climate or global warming, it’s nice to have someone come along and tell us we can spend just a little money — entrust it to someone else — and then spend time in our Hummers, use whatever lightbulb we want, and use all the appliances and electronics we want as much as we want, knowing that we aren’t contributing to the greenhouse gases in the air that might be causing global warming.
Problem is, it’s a lie. Every ounce of gas we burn idling in the snow adds carbon dioxide to the air. Every old-fashioned lightbulb in our houses uses coal or gas or oil energy in some way, adding more. To live carbon-neutral — or maintain a lifestyle that adds zero carbon dioxide to the atmosphere — we must either stop doing the things that add carbon dioxide to the air, or find things that take it out of the air once it’s been added.
For this reason, millions are interested in carbon offset credits. These are units sold by companies that find ways to either reduce emissions or increase absorption of greenhouse gas. The most common carbon offset method is planting trees. Other companies invest money in developing nonpolluting energy, or find ways to “bury” carbon dioxide in the earth’s crust.
A Poem As Lovely As A Carbon-Eating Tree
Everyone loves trees — graceful green supporters of the sky. So it’s easy to believe that planting trees in your backyard or farm or a local park will indeed help reduce the carbon dioxide in the air and combat global warming.
But you may not have all the information. If you live in a tropical zone — which for Americans is the southernmost part of Florida or anywhere in Hawaii — planting trees may well fight global warming. If, however, you live anywhere where trees lose their leaves annually, you’re actually heating up the environment. Why? Dark colors absorb heat from the sun. Light colors — like snow, for instance — reflect that heat. Leaves, when they rot, produce carbon dioxide. And evergreen trees, though they don’t consume a huge amount of carbon dioxide, warm the earth by absorbing sunlight. The net effect in northern areas is a generalized warming.
Another problem: new-growth forests consume more carbon dioxide than old forests. That’s because young trees are vigorously growing, and they’re unlikely to die or have fallen branches. Older trees don’t grow as much so don’t consume as much carbon dioxide. They also drop more branches and are more likely to die. A simple rule to remember: dead tree material produces carbon dioxide when it rots, just like burning coal or oil does.
Most scientists who have studied using trees to counteract global warming agree that only trees planted in tropical zones, and preferably younger trees, with older trees being harvested to create items that will not produce carbon dioxide — tables or chairs or cabinets. They also advise strongly against monoculture tree farming — that’s where one type of tree is grown to the exclusion of all others — because these types of forests are more prone to disease and destroying local ecosystems. Still, when carbon credit companies sell you your credits, they’re just as likely to support these types of reforestation projects as proper, multispecies jungle projects with good forestry management.
One exception to the jungle-only rule: planting trees in cities, where they block sunlight from hot asphalt and other dark stony surfaces, can result in a net cooling of the always-warmer air in a city; this practice also results in good absorption of carbon dioxide right where it’s generated.
The moral: know what carbon offset companies are really doing with your money.
When Forests Are First Planted
So Indonesia is planting vast rain forests, converting existing peat bogs into oil palm plantations that can be harvested by a chronically poor population. Great, right? No. Indonesia, because of this conversion, may now be the third largest net producer of greenhouse gases in the world. Planting the forests requires an expenditure of fuel, which will produce greenhouse gas. And in peat bogs, anaerobic (non-oxygen-using) bacteria efficiently trap carbon dioxide underground, gases which are released when the rich soil is tilled to plant trees.
The result: if you plant too fast, your situation gets worse. Gradual introduction of new forests, along with the preservation of older ones, is more likely to work in the way carbon offset companies want. You can move a little faster in tropical areas, as healthy trees will grow as much as three times faster than they would in more temperate climates. Once the seedlings are established, they will remove up to fifty pounds of carbon dioxide annually, each. That’s significant. (When they reach maturity, this will slow down, and the tree will need to be harvested and replaced in proper management.)
How Many Trees Can We Plant?
Okay, so reforesting rain forests in tropical areas, managed properly, can achieve what carbon-offset companies promise. How many trees can we realistically plant?
It’s hard to find firm numbers on this. Environmental agencies and companies that can profit from carbon offset programs tend to use numbers that look really bad: only 2% of the Earth’s surface is covered by rainforest, for instance. Other studies have turned up numbers like 6% (the most common number),8%, and 14%. Calculating this, I assumed that the 6% figure was probably right, and that we could have up to 14% of the earth’s surface covered when good reforestation plans are followed. I also assumed a generous 900 trees per acre could be planted to produce a healthy ecosystem.
In addition, most companies estimate that 900 trees will offset the carbon production of the average American. I did the math for this myself as well, and came up with a more reasonable 300. So I’ll use that number too.
(You can see this is not an exact science — which is one of the reasons I’m very leery of it. If they can’t have matching numbers or at least numbers that come within one or two standard deviations of one another — why should I trust their science? It’s religions that expect you to take statements on faith.)
With these numbers, I came up with 2.9 billion acres of land that could be turned into rainforest, which would easily be enough to take care of everyone.
But there are some problems with this number. First, you can’t really convert all the land into rainforest. It must be managed, and the people who do this must live somewhere, shop somewhere, and convert trees into carbon neutral products somewhere. And you’ll need a lot of foresters; good jungle is very difficult to navigate in any way other than on foot or horseback.
You also absolutely must add some carbon to the atmosphere when you drive through the jungle, cut trees down, or plant fresh plots. It’s either that or building more houses for more foresters who will be forced to use stone-age tools to take care of the forests.
Then you have the issue of land ownership. Someone farms all that converted land. Governments control it. It’s used for much more than just jungle today. Anytime you start requiring land to be converted to some other use, you’re going to have resistance.
And finally, you have money. I’m sure everyone can agree that we should not pay our foresters and caretakers of this hypothetical new jungle third-world wages. They need to be educated in the care of these forests. They must be able to have a life, spouses, children, homes, gardens, clothing, vehicles, medical care, stores. They will answer to an upper management who must have office buildings. The shareholders in the companies must be able to make a profit, or they’ll remove the money invested. Governments where these jungles are located will almost certainly want a cut.
One other thing to remember: trees are temporary. When it decomposes or burns (and even those made into cabinets will decompose eventually), all the carbon in them is released back into the atmosphere. By burning fossil fuels, we’re releasing carbon that has been trapped for eons that the trees are capturing back into themselves. Eventually, we will reach an equilibrium where we can’t capture carbon with forests effectively anymore.
Is It Worth It?
The last problem with using carbon offsets: it may dissuade people from reducing their carbon emissions by simply driving less and using electricity intelligently. There are only so many trees we can plant, and we are using increasingly more fossil fuels to run our lives. As second and third world nations move forward industrially, this will only get worse.
Do we want to purchase time again with carbon offsets — or would it be better to not go for the quick fix this time? There are hundreds of ways we can improve our energy consumption habits that will stop the production of carbon dioxide, rather than trying to recapture it once it’s loose. While reforestation toward the goal of stopping global warming is laudable, it should not distract our attention from the fact that not polluting to begin with is much more effective and reliable — and we know for a fact that it works. We can’t yet say the same about reforestation.