At the risk of alienating half of my faithful readers, with the upcoming Climate Change conference in New York, here is my take on why climate change skeptics might be...uhhhh.....skeptical.
In the following graphs, I have compared changes in global temperature to changes in CO2 (the alleged ring leader of the heat trapping gasses) concentrations.
[Temperature data is from NASA's Goddard Institute for Space Studies and CO2 data is from the U.S. Department of Commerce / National Oceanic & Atmospheric Administration / NOAA Research.]
The IPCC (Intergovernmental Panel on Climate Change - the UN's body that publishes the various climate change reports) has stated the concentration of CO2 in the atmosphere is the key - and essentially only - driver of temperature changes. They have been saying this - quite forcefully - for decades.
And the first graph certainly supports that correlation.
The red line depicts changes in global temperature from the long term average, using a five year rolling average to smooth out short term fluctuations. Or weather as we like to call it.
The blue line depicts CO2 concentrations in parts per million, PPM. The CO2 line looks to be straight, but the year over year increases are just very consistent.
And for the last 35 years the two do seem to move in lock step. I don't need a big, fancy climate model to see that.
Okay, so let's zoom in, eh, on the last 15 years or so.
But one of the major pitfalls of looking at data like this is mistaking correlation for causation. Just because two sets of data are correlated does not necessarily mean one is causing or driving the other.
Which is what I think the IPCC has done.
They state emphatically that CO2 and only CO2 is responsible for global temperature increase.
"Could it possibly be due to solar activity?"
"What about the El Niño effect?
"Changing Jet Stream?"
The next graph shows the predictable increase in CO2 concentration over the last seven or eight years.
And this is where the IPCC models predict imminent disaster if this trend continues. Because we can easily see what their models will predict for temperature increases for those eight years - and beyond. OMG!
But.......wait for it......big finish.......
Here's what actually happened.
Temperatures have remained essentially constant during that time. What?
This is what the climate heretics have been saying for the last decade - are you sure it is CO2 driving temperature change? Could there be something else?
Recently, the IPCC did have to admit that of their 117 climate models, 114 got it wrong. Ouch.
But, supporters say, this is the hottest it's been in 200 years.
But the key question is; is CO2 driving it? Or could it be something else?
In the statistics business, confusing correlation with causation has a name. It's called "Ice Cream Sales Cause Shark Attacks!"
Because if you only look at the data, as ice cream sales increase, so do shark attacks. As sales drop off, so do shark attacks. Every year. Year after year. Oh my God, for the love of humanity, we must stop selling ice cream!
The obvious point here being, there is something else driving both of these. And coincidentally, it's called temperature. Oh my God, for the love of humanity, we must stop the temperature from increasing!