April 25, 2009
By the numbers ye shall know them
Divide By Three
To understand what will probably happen to Earth's climate over the next century, you only need to look at the estimates of global warming alarmists and divide by three. Shh. Don't tell them or they will just multiply their current figures to compensate.
There is no doubt that CO2 is a greenhouse gas and pushes up the temperature. Nobody is arguing that. But CO2 pushing up the temperature is a first order effect. It would only contribute about 1 degree of warming over the century if CO2 doubled to 580 parts per million.
The people who want you to stay awake nights worrying about climate change have a theory that CO2 will somehow cause water vapor to retain more heat, and that this will multiply the effects of CO2 by 3 (some of the more absurd alarmists claim even more).
The problem is there is no evidence of this actually happening on this planet. The reason is that the alarmists couldn't correctly model cloud cover, which looks as though it counterbalances the effects of CO2 to a certain extent, preventing much greater warming.
The history of modern climate goes back 11,000 years, to the end of the last Ice Age. Most people know that the climate has warmed since the end of the last Ice Age, and that sea levels have climbed as the Ice melted. But few people realize that most of that warming happened during the first 1,000 years after the Ice Age ended, and that since then global temperatures have fluctuated within a fairly narrow band of between 14 and 16 degrees.
And what the alarmists will never tell you is that we are still within that fairly narrow band of temperatures. We are, many geologists feel (and oh, how alarmists hate geologists--they tend to have a sense of perspective) recovering from the Little Ice Age shown in the chart I linked to.
Temperatures have been warmer than they are today. For half of the past six million years, temperatures have been warmer than they are today. More recently, during the past 11,000 years, temperatures were warmer during the Holocene Optimum, the Roman Optimum and the Medieval Warming Period. Notice the use of the word 'optimum' in describing these epochs. The warmer temperatures were quite beneficial to us, allowing humans to grow wine in England and plant crops in Greenland.
CO2 now exists in our atmosphere in concentrations of 386 parts per million. In the past, concentrations have been as high as 6,000 parts per million. And despite that, there has been no runaway burning up of the planet and the normal climate cycles have continued. Because that's what climate does. It changes.
The Earth will continue to warm and the sea levels will probably continue to rise for the remainder of this inter-glacial interlude. Our contributions of CO2 will have a slight effect, increasing the temperature about one and a half degrees this century.
So if you take the predictions of the panicologists who want you to completely change the nature of your life and our society and divide by three, you get a fair idea of what's actually going to happen.