It’s not often that I’ve taken a request on Major Karnage, but in response to some criticism that I had of a rather inane rant about the carbon tax, I was asked what my stance is. I will, therefore, try to briefly explain the whole climate change debate from my perspective. The first post will deal with climate change in general, the second will deal with the carbon tax specifically.
The whole climate change debate really, at the end of the day, is about the science. What I find ironic/depressing is how so many people, the author of that post included, seem to take what is said about a “scientific consensus” at face value. On the other hand, the critics of climate change often seem to display an alarming degree of “confirmation bias” – lauding anyone that attacks climate science, no matter how dubious their credentials. I take the view that to be able to argue confidently on these kinds of issues, it is essential to actually understand the science – don’t take Gillard’s word for it or Abbott’s. In fact, don’t even take my word for it. I feel like the whole world is up-in-arms over this issue, yet the most vocal proponents of carbon taxes seem to have taken everything they know about climate science from an Al Gore documentary.
So what does the science say?
Before I start, just so everyone knows, I do have a science degree – meaning that I can read scientific articles and know what they’re on about, but I’m not exactly Stephen Hawking.
The best summary that I’ve seen was done by The Royal Society and can be downloaded HERE, while the best collection of graphs and pictures comes from NASA and can be downloaded HERE (look at the second half for the graphs). As the Royal Society report notes, there is a general (but not unanimous) agreement that the Earth’s surface temperature has increased over the last few decades and that CO2 levels have increased significantly as a result of human activity. Also, methane levels have increased, probably due to human activity but possibly due to other factors. There is proof that there is a “greenhouse effect”, in that these gases can trap solar energy in our atmosphere and so increase the temperature.
That said, the climate is extremely complex and there is a lot that is not yet known. Climate models are becoming more and more sophisticated, but they are still extremely simplistic and do not yet have the capability to include all of the variables that we know cause the climate to change. There are even some things that are very poorly understood, as well as a hell of a lot that we do not really consider. For instance, there is very limited understanding of natural “carbon capture” – where CO2 is stored in soil and plants – even though it is estimated that 50% of all human emissions are taken-up in this way. Also, temperature readings from more than 150 years ago are very inaccurate – they mostly rely on readings from gas bubbles trapped in glaciers. In the geological scheme of things like the climate, 150 years is nothing.
Finally, our attention spans are really too short for the whole debate. Climate change does not happen over days, months or even years – it happens over decades, centuries and millennia. A particularly cold winter, or even five winters, does not mean that the world is not warmer over a 20-year period. Similarly, a particularly warm 50 years may mean nothing over the course of a millenium.
The longer the period of time that you are looking at is, the clearer the trends will become. The graph above shows this – it is using the moving average over 5 years (red) and 11 years (blue). Compare that to the one below, which has one month and one year averages – this shows how it is possible to choose a time period that will show cooling, but this does not fit with the overall trend (as seen above).
The reality is that the climate is, incontrovertibly, getting warmer. There is not a lot more to say on the subject – people who refute this are either ignorant or dishonest. That said, there is a lot that “warmists” don’t like to talk about.
What we don’t talk about
There are also a lot of factors that affect the climate that no one in the debate seems to be really mentioning. Remember how greenhouse gasses trap sunlight that was reflected from the Earth? Well, as everyone who has worn a black suit on a hot day will know, dark colours absorb heat, whereas bright colours reflect it. This has a huge net effect on the environment – the more of the planet’s surface that is dark (i.e. rainforests, farmland, black rocks), the more energy is absorbed and vice versa. Because of this, clouds actually create a significant cooling effect, as does deforestation. However, water vapour in the atmosphere that does not form clouds acts as a greenhouse gas in fact, less water vapour in the atmosphere reduced global warming by 25% over the last decade. I’m waiting for a steam tax…
Another thing that causes global cooling is pollution. Yes, you read that right. There was no global warming for 100 years after the industrial revolution started, despite huge levels of CO2 emissions. Why is this? Well, pollution was a lot dirtier at the time – particles of soot and smoke prevented sunlight from reaching the planet’s surface. Similarly, volcanoes have found to have a significant cooling effect because of the ash emitted, as well as the sulphur dioxide (SO2) emitted high into the atmosphere.
This is even assuming that we know everything that causes global temperatures to change, which may well not be the case. The climate is thought to have changed significantly in the last 2,000 years – ancient writings sound like a hotter world than today, then there was a mini-ice age that ended somewhere around the 1500s. There is not, at this time, a causative link between emissions and warming. This means that we know that emissions have gone up and that, in theory, emissions cause warming; but we do not know for absolute sure that the one caused the other, it’s just a correlation.
In fact, we know that warming increases levels of CO2 . There are billions of tons of CO2 dissolved in water on the planet. CO2 is also what makes the bubbles in sparkling drinks. When you leave Coke in a warm place, the CO2 escapes and the drink becomes flat – the same phenomenon means that warmer oceans emit huge amounts of CO2 (are we going to start taxing the Tasman?)
Obviously, this post was just the – wait for it – tip of the iceberg. People spend their entire lives studying this stuff; I’ve spent a few hours reading some scientific journal articles and you just spent 10 mins reading a blog post. The take-home point point is this: nothing is certain. And arts students really need to stop lecturing me about “understanding the science”.
Stay tuned for Part 2, where I’ll talk more politics and less science.