Climate change basics

It is something we can’t see, or smell. We may not be able to notice any visible problem in our own backyard for many decades yet, but we need to realise the full cost of CO2 emissions from fossil fuels VERY SOON, as the bill for the arrears is on its way.

The sun provides this planet with energy, but nowhere near enough to prevent the earth from being a frozen lump in space, an ice world not unlike the moons of Saturn. Life is possible because a shield of CO2 stops the energy from the sun that hits the earth from escaping back into space. It’s our invisible little blanket. Throughout the history of the planet, the CO2 layer has varied, and our climate frequently changes. In our lifetimes, the planet has been in a ‘sweet spot’, the CO2 layer is not too thin and not too dense. This allows a huge diversity of living things to flourish from the vast swarms of plankton that whales eat in Antarctica, to the huge fields of crops that are adapted to our current climate and keep us alive.

CO2 can naturally enter the atmosphere from processes like volcanos. Plants suck this CO2 out of the atmosphere and then store the carbon in their stems and leaves, and also let out oxygen. This has kept the world a pretty nice place to live for a long time. About 300-350 million years ago the earth was mostly ocean with lots of shallow swamps full of ferns and other early plant life. The CO2 concentrations were 1500ppm, about 4 times more than today and the earth was hot, about 10 degrees Celcius higher on average. There were no humans or dinosaurs, the land was ruled by plants and giant insects. So much plant life was growing and sucking up CO2 that 50 million years later the CO2 levels fell to almost the same as current levels. The big decaying mats of swamp plants were squashed by geological forces into a gooey liquid (oil), or a soft rock (coal). We call these products fossil fuels, as they are literally the fossils of these prehistoric plants. Humans much later discovered that when they burned a tree they could release a hundred years worth of the sun’s energy stored as wood. This could heat a cave and fry meat. It allowed us to multiply and grow big brains. When we found coal, millions of years of energy could be released instantly, enough to melt rocks and make iron and steel. By burning oil, we have also been able to ‘bring to life’ the steel parts of a complex array of new machines that we now rely on. Unfortunately, this burning also releases millions of years worth of carbon from 350 million years ago, in the form of carbon dioxide gas.

Our planet’s little CO2 blanket is getting denser and our planet is warming. Our atmosphere is heading back in time to what it was like hundreds of millions of years ago. The science of this isn’t too hard, we can detect CO2 levels with scientific instruments, and gas bubbles trapped in Antarctic ice allow us to map the CO2 history of the planet. While CO2 emissions have always happened naturally, this stable rate of release changed dramatically when we learned how to use fossil fuels. Now we are supercharging the atmosphere.

Every year the earth naturally pumps out around 500 million tons of CO2 from volcanoes. That is less than 2% of the amount that is being pumped out by humans every year. Australians alone produces 409 million tons of CO2, China produces 10,540 million tons, the USA half of that. A vent in Hawaii (Pi’u O’ o) emits 3.3 million tons annually, about one sixth of Sydney’s human output. You can’t see or smell CO2, so try to imagine Sydney or Melbourne ringed by 6 Hawaiian volcanos instead. Source;CSIRO A review of the recent geological record (the last 800,000 year) shows that the recent very extreme CO2 concentrations are new. What is also new is that these extreme increases have occurred in a few decades, not in thousands of years. One estimate says that CO2 emissions are occurring at a rate 60 times faster than normal.

Using indicators of what temperatures may have been in the past, and without using any fancy modelling, there seems to be a direct relationship between CO2 and the earth’s temperature (There is fancy monitoring too and that says the same thing). The temperatures in the past are worked out using things like, tree rings, coral specimens and pollens in sediments. CO2 is up and our planet is getting hotter. When Vikings found pastures in Greenland and Romans grew grapes in the England, the North Atlantic and parts of Europe were warmer than they are today. However, the current changes are not normal cyclical events. The Medieval Climatic Anomaly was localised, other areas of the planet were colder at the same time. What we are talking about now is something global, way bigger and faster.

So far, our oceans have been soaking up a lot of the excess carbon, causing slow changes in the acidity of the oceans that will make life there a lot harder for many plants and animals. It can’t soak it all up forever. What worried me recently is that I went to a seminar where scientists weren’t the least bit concerned about the ‘ifs’, but the ‘how soon’ and ‘how bad’ questions. The science around climate change has more scientific consensus than the theory of evolution. They are quite calm when suggesting that we MAY have about 10 years to do something, before this runaway locomotive really starts heading downhill and really picks up some speed. We can’t fix it up later, any temperature increases would take thousands of years to rectify even if we stopped pumping out CO2 now.

There is plenty of information about the impacts on marine life, and they are already easy enough to see in global hotspots like eastern Tasmania. The biodiversity of the planet is already declining (it was slowly declining even without climate change). We don’t yet really know how much it will affect humans, there will be winners and losers, but it’s not a good start to be on one of the world’s drier continents as rain patterns alter.

The problem with this debate is that the problem will take hundreds of years for the effects to fully play out, way beyond our immediate lifetime and concerns. The 100 year impacts are already potentially bad on things like biodiversity, crops, storm events, and flooding, but it’s the 300 year impacts that are really in doomsaying territory.

My family arrived here in the 1830s and helped to build a new civilisation in the south, living in subsistence poverty and struggling to get wheat and orchards to grow in an alien climate. The inheritance from 6 generations of hardship looks like it might be squandered in one, with the next 6 generations picking up the tab if they survive long enough. I think if we are asked to pay a few cents more on petrol and power, that is a cheap insurance policy against the risk that our grandchildren and their children might one day pay the equivalent of $50 for a loaf of bread just to sink backwards into Dickensian squalor, in a sterile world devoid of living things. There is still time to make other choices, but not much time.