We here at T.U.W. hope you are enjoying your celebration of the original Brexit.
The following post is admittedly crude, and will be put into extreme amounts of detail should I ever get my global warming work done. But as you light off your sparklers, firecrackers, M-80s, cherry bombs, pineapples, roman candles and the like on this festive day, I wanted to have you get a sense for just how much you are likely contributing to the boiling off of the world’s oceans and the ultimate baking of the planet.
Now, you are going to see estimates with a wide range of variability around them, so keep that in mind as I put out these numbers. We’ll light our 4th of July fireworks with a Socratic fuse today.
How much carbon dioxide has “humanity” emitted through the combustion of fossil fuels since the 18th century?
This is where you will see varying data, but the best I can surmise is that the amount of fossil fuels burned between, say, 1750 and 2015 have released about 1,500 gigatons of carbon dioxide into the planet’s atmosphere. Remember a couple of things. First, is that the Earth’s carbon budget is fixed, and that there is a long-run planetary carbon cycle that is eventually going to take most (not all) of the CO2 that we put into the atmosphere, put it back into the oceans, and eventually back into rocks, and then back into carbon dioxide and then back to the ocean, then rocks, and so on. And while this may be cause for comfort, of course the carbon cycle takes place on geologic scales that make human civilization’s time on earth seem tiny in comparison, so we can’t just let'”nature take its course” to solve our climate issue. Second, “we” emit about 35-40 billion tons of carbon dioxide into the atmosphere today through our activities. The total amount we have emitted, 1,500 gigatons, is 1,500 billion tons. That’s just some perspective.
How much carbon dioxide remains in the ground embedded in burnable fossil fuels?
Aha it is interesting to see discussions here, because it tends to pit one brand of Malthusians against another. I tend to think that there is a lot more fossil fuel energy in the ground than even our best estimates suggest, but that is another story for another day. As best as I can tell, folks seem to think that the amount of CO2 embedded in all current reserves held by fossil fuel companies, in all expected reserves that those companies may access in the future, and all other non-traditional reserves including those owned by governments are somewhere in the 3,000 billion ton range.
What will happen if we burn all of this?
Well, remember that burning all of this will take a long time, and that while fossil fuel resources are cheap, they still will be competing with developing energy technologies in the future. It is hard to think that we will burn them all in the next couple decades, my bet would be closer to the multi-century time scale, but for fun let us assume we will burn ALL of the stuff in the coming decades. I’d like to NOT rely on models and hyperbole for the time being, so our guess about what this will do is going to come from what has happened in the data, in the real world, in the past.
Since 1750, the globe has warmed to the tune of about 0.8 degrees Celsius on average. Over that time, we have burned 1,500 billion tons of CO2. For argument’s sake, let us foresake the data just a little bit. Let us say that we have warmed by a full degree, and let us also say that the CO2 that we have tossed into the atmosphere has not yet brought us to full thermal equilibrium, so that we can expect, even if we stopped adding CO2 entirely today, to see the world warm by another 0.5 degrees by the time I have great grandchildren. In other words, by moving 1,5000 billion tons from beneath the ground and into the atmosphere faster than the earth would have done so on its own, we have warmed the planet, on average, by 1.5 degrees. NOTE that to this day, we have seen only 0.8 degrees of warming, so this is a pretty conservative assumption that again relies on some scientific models. The global thermometer only reads 0.8 degrees higher today, not 1.5.
Be that as it may, if we instantly add 3,000 billion more tons of fossil fuel CO2 emissions to the atmosphere, based on how the climate of the past has responded to past CO2 additions, then it appears that we will, at most, increase the temperature of the planet by another 3.0 degrees Celsius. This is about 5 1/2 degrees F — or about the difference between the temperature of New York City and Oklahoma City. Note that this would imply that the TOTAL amount of warming we would get from burning every single molecule of fossil fuels in the Earth’s crust would be about 4.5 degrees C. If you were to look at the high end estimates from the “middle” scenarios of the climate change models, this is actually the amount of warming that the models would predict, at the 95th percentile, from a doubling of CO2 from pre-indusrial levels, not from burning every ounce of fossil fuels there is. We will cover later what it would take to hit the CO2 scenarios from the scary RCP8.5 scenarios from the IPCC global warming science.
Note that I am not saying that we can or will burn all of these fossil fuels. Note that I am not saying anything about the climate models. Note that I am not saying anything about projected climate sensitivity and what and where the climate feedbacks come from. Rather, I am sort of doing what the Club of Rome folks (and many before them) pioneered before them. I am looking at past trends in temperatures as they relate to CO2 emissions by humans, and I am asking, as they often do, if present trends continue …
And what do we find? If we burn all of the fossil fuel that we can possibly burn (and I am ignoring all of the related pollution and air quality and other problems with this), which as I said is highly unlikely, then even a generous and conservative estimate of how much warming we will get suggests at most 4 and a half degrees of total warming above where we were at the start of the industrial revolution, or only another 3 degrees above where we are today. If you take the historical relationship more literally, and again there is no scientific reason to either do it or not do it, it is a simply algebraic exercise, then we would expect to see only another 1.6 degrees Celsius of warming if we burn every single molecule of fossil fuels.
Again, this is amateur stuff, but the question is worth asking nonetheless: can we burn the planet, even if we wanted to do so? It is not clear.