Rethinking Lifestyle

A Big Greenhouse

  • David Dawson, Guest Author
  • Retired Beekeeper, Environmental Activist

Everyone knows that if you leave your car outside in the sun with the windows closed it get hot inside – very hot even. The other day I was in a greenhouse with simple plastic cover and it was remarkably hot inside even though it was below freezing outside.

In the old days houses were insulated with wood shavings. Then fiberglass was invented and that has now completely replaced wood shavings. Probably the oldest insulating material is natural wool or feathers, but technology has given us Styrofoam, polyester or even cellulose fibres. Gases have insulating properties too. For example, manufacturers of double or triple pane windows put an insulating gas between the layers of glass – and I’m sure that is welcomed by everyone…and thus everyone must accept that gases can insulate.

As you can see there is a variety of insulating materials, including gases, and even a single layer of plastic traps the heat in a greenhouse. The atmosphere is made up of approx. 78% nitrogen, 21% oxygen and 1% other gases, including carbon dioxide. For all the time man has been on planet earth this atmospheric mix has been constant, even through various ice ages. It just happens that the temperature range on earth is ideal for life as we know it. Maybe on Mars or other planets, life forms will be totally different because of different gas ratios and different temperatures. We may never know.

The reason why Earth’s temperature has remained stable for so long is that the incoming radiation from the sun during the day is sufficient to compensate for the loss during the night: it is the historical mix of gases that allows the world’s temperature to stay in equilibrium. However for the last 100 years we have been burning more and more carbon-containing oil and coal. The carbon combines with oxygen in the atmosphere turning into carbon dioxide that is released into the atmosphere, for example from the exhaust pipe of your car or truck. As you agreed above, gases can insulate and for the record carbon dioxide is an insulating gas – much more so than nitrogen or oxygen.

The net result is rather like that plastic on the greenhouse. The world heats up due to the sun but the insulating effect of carbon dioxide in the atmosphere prevents more of the heat escaping during the night. The more insulation you have in your attic the warmer your house will be, but in the planet’s case it is more insulation in the atmosphere that is causing the world to heat up. It’s simple really.

For the record, worldwide we humans are generating 40 billion tons of carbon dioxide every year. Some gets absorbed into the oceans as carbonic acid and thus acidifying the sea, some gets absorbed in trees but worldwide we are cutting down more trees than are re-growing, so most ends up in the atmosphere as an insulating layer like the plastic on the greenhouse.

The purpose of this article is to give you, dear reader, a different perspective on the cause of global warming and even convince a few people that do not yet believe the climate is changing. Have I succeeded?