Читать книгу Harmony: A New Way of Looking at Our World - Tony Juniper - Страница 10

Giant ferns that grew in carboniferous swamp forests 300 million years ago and microscopic plankton that once drifted in the oceans, were among the organisms that helped to create the coal, oil and gas deposits that now drive the modern world. Provided by the sun, energy that flowed through living organisms long ago in the Earth’s past was trapped, transformed and then held tight in the hydrocarbon compounds that now power our industrial societies. That energy source, which took hundreds of millions of years to accumulate gradually, is being used up all at once, and the carbon that was, in the process, taken out of the air and stored away over such vast periods is being released as carbon dioxide in a great single pulse. As a result, we are upsetting a balance established over millions of years, and on a massive scale. This is an indisputable fact and it seems to me that the ice cores and the graphs drawn from the Mauna Loa measurements act as a cold, silent and independent witness to the changes that have occurred after more than two centuries of industrialization.

RIGHT: This satellite image, covering an area approximately 2 miles wide, shows intact rainforest in green in the south of Brazil at the top of the image and agricultural land at the bottom of the picture across the border in northern Argentina.

However, it is not only fossil fuels that are causing an ever more pressing atmospheric crisis. Around a fifth of annual human-induced carbon dioxide emissions come from the continuing clearance of our planet’s forests, particularly the tropical rainforests. During 2007 I received the direst warnings from leading scientists as to the implications of this particular trend.

The tropical rainforests are to me without doubt the most incredible terrestrial ecosystems on Earth, and for a considerable number of years I have been working hard to convey this fact to as many people as possible. They are literally the Earth’s air-conditioning system, and are also a vital mechanism that moves water around the globe. Without them we would have less of the rain that, for now, allows crops to grow and farms to thrive, but they are also enormous carbon storage reservoirs. Billions of tonnes of carbon are locked up in them, but as the rainforests are degraded and cleared away by logging operations, or replaced by cattle pasture, or with plantations of commodity crops, such as soya and palm oil, the carbon that was once in the trees and the soil beneath them is transferred to the atmosphere as carbon dioxide, adding to the burden of greenhouse gases.

What makes matters considerably worse is how the tropical rainforests also absorb about 15 per cent of our emissions, such as those from cars and power stations. As they are cleared, so their ability to reduce the impact of our emissions from industry and transport is diminished. More than a third of the tropical rainforests have already been removed, the vast majority since the 1950s. The rest are fast disappearing, as demand for land to grow the crops that feed global commodity markets spirals upward. This is for me one of the greatest tragedies of our age, not least because it is unnecessary.

Necessary or not, the increased levels of carbon dioxide brought about principally because of fossil fuel combustion and deforestation have already led to an elevated global average temperature. Scientists are now confident that the net effect of human activities since the mid-eighteenth century, when coal use began to rise rapidly, has been one of warming. Global average temperatures have increased by about 0.8° Celsius since this time and there is strong evidence that most of the observed increase in temperature since the mid-twentieth century is directly attributable to increases in anthropogenic carbon dioxide and other greenhouse gases. This is now a mainstream view, backed by a vast body of scientific evidence.

Of course the changes we have caused to our planet’s atmosphere were not an intentional or conscious act. They are the inadvertent results of how we have grown economies, made life more comfortable and promoted people’s welfare. They are unintended consequences of what we have come to call development, and the process continues today as we seek to expand our comfort and solve problems in ways that generate yet more greenhouse gases. But it is different now, not least because I don’t believe we can go on any longer pretending that we do not know about the problems we are creating. Thanks to modern science we now know the consequences of the way we have chosen to live, and the way we have become used to meeting our needs – and we are also increasingly aware and informed about the grave legacy we are leaving for those who follow us in the near future.

OVERLEAF: Moon rise over an oil refinery. Refineries heat crude oil and pass it through catalytic cracking towers. Pollution released in the process causes the moon to appear red.