Understanding the science behind global warming

I would like to spend my next few blogs discussing the risks and opportunities presented by the need to move to more environmentally sustainable supply chains.
But first I want to spend a few moments discussing some of the basics we need to understand about the issue of global warming. Hopefully I can explain it to you in a slightly different way than you may have heard before.
From all we’ve been hearing in the media lately about carbon dioxide levels, you would think there’s tons of carbon dioxide about.
Yet CO2 is actually rare in the atmosphere. Fewer than 4 out of every 10,000 atmospheric molecules are CO2 molecules. But CO2 is the most abundant of the greenhouse gases (others include methane, nitrous oxide, HFC and CFC). And it’s produced every time we burn something and every time something decomposes.
And greenhouse gases are critically important because of their ability to trap heat near our planet’s surface.
If you want a mental picture of greenhouse gases at work, think of trying to sleep on a muggy August night in a Toronto apartment building downtown – without your air conditioner on. Now think of trying to fall asleep in a desert . For those of you who haven’t had the opportunity to do so, I can tell you it can be downright cool.
Yet the only difference between the desert and the muggy night in Toronto is a single greenhouse gas – water vapour – which is capable of retaining two-thirds of the heat trapped by all the greenhouse gases.
To give you an idea of the power greenhouse gases actually have to influence temperature we have to look beyond Earth.
Consider Venus. The atmosphere of Venus is 98% CO2 and its surface temperature is 477C. If CO2 was to reach even 1% of the Earth’s atmosphere – it would bring the surface temperature of our planet to the boiling point
The particular challenge with CO2, of course, is how quickly we are adding to it.
Prior to 1800, there were about 280 parts per million of CO2 in the atmosphere. Today the figure is around 380 parts per million. Scientists figure we can go to about 550 parts per million over the next century before we hit the threshold of dangerous changes. That may seem like a large cushion but if we keep going at our current pace it’s estimated we’re going to hit 680 parts per million by 2100.
In my next blog I’ll look specifically at Canada’s contributions to GHG emissions as well as the contribution by commercial transportation.

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With more than 25 years of experience reporting on transportation issues, Lou is one of the more recognizable personalities in the industry. An award-winning writer well known for his insightful writing and meticulous market analysis, he is a leading authority on industry trends and statistics.

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  • Lou: If global warming is caused by the amount of CO2 in the atmosphere, then why is it they are suggesting that we are going to start global cooling. In fact it was reported a few weeks ago that the earth has actually cooled in the last 10 years. I listened to a program the other night where the speaker talked about changes in the ocean currents and that the temperatures would begin to drop because the ocean currents are now coming from the north instead of the south.
    I think that there needs to be more research done by people that are not looking for a way to make money or looking for a cause to help them feel like they have a purpose in life. Any time a competent scientist or group denies the existence of global warming they are denied credibility. We are forced into spending vast amounts of money to make changes that I am convinced are not needed. I have no problem with helping the environment and all that stuff but some of this crap is going way too far. Global Warming is becoming a joke.