Our home in space

some remarks on global heating and ocean acidity

Guy Ottewell


Deforestation contributes about 17% of the world's carbon dioxide emission.
        Plants have given us the atmosphere that we animals can breathe. They take carbon dioxide out of the air, store the carbon in their own bodies, and exhale the oxygen. When cut, and very rapidly when burnt, they do the opposite: they use up oxygen and pump out carbon dioxide.
        Forests of course do more than that. 1.2 billion people depend on forests for their livelihood.
        In Brazil, forests are being destroyed at about 7,000 square miles a year. This started in the sparser woodlands of the southeast and is working into the taller and denser forests of the central Amazon basin, so the rate of carbon dioxide emission is increasing.
        The deep forest that once made Borneo (the huge island divided politically between Indonesia and Malaysia) almost unexplorable is being lost to illegal logging at a square mile a day — the world's worst rate. From the 1960s to 2011 the primary forest has shrunk from 100% to 5%. (Native peoples have been driven out, the bared ground planted with oil palm for fuel, investigators threatened and expelled. It is, according to former British Prime Minister George Brown, “probably the biggest environmental crime of our times.”)
        It's not only tropical rainforests that are being destroyed, but also the boreal forests that cover much of Scandinavia, Russia, Alaska, and Canada, and account for a third of the world's remaining woodland. The destruction is a network of feedback loops. Not only logging but mining and damming destroy trees, as does the cutting of thousands of miles of roads to reach these activities. The warming itself causes an increase in forest fires and in destruction by insects. In Russia forest fires are happening twice as fast as in the 1990s.
        Could we, by planting trees, extract from the air the amount of carbon dioxide we're now putting into it? Yes, but only by planting every year a new area the size of India.
        China, Vietnam, and Costa Rica are among the few countries that have managed to shift from deforestation to reforestation.