Let’s get facts right on climate change
The terrible smogs in China (Mail) are the result of vehicle exhaust particulate pollution, not carbon dioxide emissions as was incorrectly stated by the Channel 4 science correspondent. Carbon dioxide on its own is a clear, colourless, non-toxic gas. I hear a lot of bad science being spouted during the Paris climate talks. Studies have proven that air pollution actually prevents sunlight from reaching us, so smogs actually cool the ambient temperature rather than raising it. This has been demonstrated repeatedly by volcanic eruptions which emit airborne particulate aerosol matter. The volcanic eruptions of mounts Pinatubo and Tambora resulted in lower temperatures worldwide, known as the years without a summer. Smog and pollution do kill people but shouldn’t be confused with pure carbon dioxide emissions: carbon dioxide is good for both plants and ocean life. Air pollution lowers temperatures. After the 9/11 attacks, for instance, all planes were grounded in New York. Because the skies were clear of hazy aircraft vapour trails, the sunlight was able to reach the earth unfiltered and temperatures shot up in New York. I wish science reporters would get their facts right. The Chinese smogs will result in respiratory deaths but will lower global ambient temperatures, not raise them. I’m all for clean energy but clearer, non-polluted skies will lead to greater sunlight radiation reaching earth and warmer temperatures, boosting crop production.
SUSAN THOMAS, Oxford. I WAS disappointed to see the Panorama programme on emissions gloss over the issue. Ten years ago in the U.S., truck and engine manufacturers came up with diesel exhaust fluid (DeF), a urea-based fluid injected into a catalyst in the exhaust system which converts nitrous oxide/dioxide (NOX) emissions into ammonia and water. This system is in universal use in large commercial vehicles, and now in all diesel cars imported into the U.S., with the exception of VW. The now-infamous VW deception allegedly came from the vehicle engine control unit recognising when the emissions were being tested and switching in a DeF supply. If this is the case, the explanation supplied by VW that it was just a rogue technician is nonsense. In the UK and europe, however, DeF is used in trucks but not yet in all cars because the emission controls we have are concerned only with CO2, not NOX. I’m afraid the advisers our Government uses on emissions know nothing about diesel engines, or they would know how polluting they are.
TIM BURD, Southampton.