Tar Sands vs. Coal

The term “fossil fuels” is a very large umbrella. Coal, oil, and natural gas are the usual distinctions, but there’s also unconventional oil (such as the Alberta tar sands) and unconventional gas (such as shale gas from fracking). “Unconventional” means that the fuel is produced in a roundabout way that’s less efficient and takes more energy than regular fuel. For example, oil in northern Alberta is mixed with sand and tar that’s difficult to remove. As global supplies of conventional oil and gas decline, unconventional fuels are making up a growing segment of the petroleum market.

The different types of fossil fuels are present in different amounts in the ground. Also, for each unit of energy we get from burning them, they will release different amounts of carbon emissions. Given these variables, here’s an interesting question: how much global warming would each type of fuel cause if we burned every last bit of it?

A few weeks ago, a new study addressed this question in one of the world’s top scientific journals. Neil Swart, a Ph.D. student from the University of Victoria, as well as his supervisor Andrew Weaver, one of Canada’s top climate scientists, used existing data to quantify the warming potential for each kind of fossil fuel. Observations show the relationship between carbon emissions and temperature change to be approximately linear, so they didn’t need to use a climate model – a back-of-the-envelope calculation was sufficient. Also, since both of the authors are Canadian, they were particularly interested in how burning the Alberta tar sands would contribute to global warming.

Swart and Weaver calculated that, if we burned every last drop of the tar sands, the planet would warm by about 0.36°C. This is about half of the warming that’s been observed so far. If we only burned the parts of the tar sands proven to be economically viable, that number drops to 0.03°C. If we don’t expand drilling any further, and stick to the wells that already exist, the world would only warm by 0.01°C, which is virtually undetectable.

Conventional oil and natural gas would each cause similarly small amounts of warming, if the respective global supplies were burned completely. Unconventional natural gas would cause several times more warming – even though it’s cleaner-burning than coal and oil, there’s a lot of it in the ground.

The real game-changer, though, is coal. If we burned all the coal in the ground, the world would warm by a staggering 15°C. There’s a large uncertainty range around this number, though, because the linear relationship between carbon emissions and temperature change breaks down under super-high emission levels. The warming could be anywhere from 8°C to 25°C. In the context of previous climate changes, it’s hard to overemphasize just how dramatic a double-digit rise in average temperatures would be.

The main reason why the warming potential of coal is so high is because there’s so much of it. The Alberta tar sands are a huge resource base, but they’re tiny in comparison to global coal deposits. Also, coal is more polluting than any kind of oil: if you powered a lightbulb for one hour using coal, you would produce about 30% more CO2 emissions than if you ran it using conventional oil.

The tar sands are more polluting than regular oil, but exactly how much more is a very difficult question to answer. The end product that goes into your car at the gas station is essentially the same, but the refining process takes more energy. You can supply the extra energy in many different ways, though: if you use coal, tar sands become much more polluting than regular oil; if you use renewable energy that doesn’t emit carbon, tar sands are about the same. The authors didn’t include these extra emissions in their study, but they did discuss them in a supplementary document, which estimated that, in an average case, tar sands cause 17% more emissions than regular oil. Taking this into account, the tar sands would cause 0.42°C of warming if they were burned completely, rather than 0.36°C.

Therefore, headlines like “Canada’s oil sands: Not so dirty after all” are misleading. Canada’s oil sands are still very dirty. There just isn’t very much of them. If we decide to go ahead and burn all the tar sands because they only cause a little bit of warming, the same argument could be used for every individual coal plant across the world. Small numbers add up quickly.

The authors still don’t support expansion of the tar sands, or construction of pipelines like the Keystone XL. “While coal is the greatest threat to the climate globally,” Andrew Weaver writes, “the tarsands remain the largest source of greenhouse gas emission growth in Canada and are the single largest reason Canada is failing to meet its international climate commitments and failing to be a climate leader.” Nationally, tar sands are a major climate issue, because they enable our addiction to fossil fuels and create infrastructure that locks us into a future of dirty energy. Also, a myriad of other environmental and social problems are associated with the tar sands – health impacts on nearby First Nations communities, threats to iconic species such as the woodland caribou, and toxic chemicals being released into the air and water.

Tar sands are slightly preferable to coal, but clean energy is hugely preferable to both. In order to keep the climate crisis under control, we need to transition to a clean energy economy as soon as possible. From this viewpoint, further development of the tar sands is a step in the wrong direction.

Nuclear Power in Context

Since its birth, nuclear power has been a target of environmental activism. To be fair, when nuclear power goes wrong, it goes wrong in a bad way. Take a look at what’s happening in Japan right now. Friday’s tsumani damaged the Fukushima Daiichi power plant, and several of its reactors have experienced partial meltdowns. Radiation from the nuclear reactions has been released into the surrounding environment, and could endanger public health in the immediate area, causing cancer and birth defects.

Nuclear disasters are horrifying, and this is by no means the worst that has happened. However, nuclear isn’t the only form of energy that experiences periodic disasters. In fact, over the past century, hydroelectric disasters have killed more people than all other forms of energy disasters combined.

(Sovacool et al, 2008, Fig. 1).

So why do we worry so much more about nuclear power disasters? Is it because the idea of the resulting radiation is more disturbing than the prospect of a dam breaking, even if it’s far less common?

However, an energy source can kill people without a large-scale disaster occurring. Let’s look at fossil fuels. Think of all the miners killed by coal accidents, all the people killed by smog inhalation or exposure to toxic chemicals (such as heavy metals) that are present in fossil fuels, deaths due to gas leaks, civilians killed by wars over oil, and so on. It’s difficult to quantify these numbers, because fossil fuels have been in use for centuries, but they clearly exceed the 4,000 or so deaths due to nuclear power accidents (as well as any other deaths due to nuclear power, such as uranium mining).

We must also look at the deaths due to climate change, which fossil fuel burning has induced. The World Health Organization estimates that over 150 000 people died as a result of climate change in 2000 alone. This annual rate will increase as the warming progresses. If we don’t step away from fossil fuels in time, they could lead to a devastating amount of death and suffering.

Fossil fuels are silent, passive, indirect killers which end up being far more destructive to human life than nuclear power. However, much of the public remains opposed to nuclear energy, and I believe this is a case of “letting perfect be the enemy of good”. I feel that we hold nuclear power to an impossible standard, that we expect it to be perfect. It’s certainly not perfect, but it’s far better than the existing system, which desperately needs to be replaced.

There are also exciting developments in nuclear technology that could make it safer and more efficient. In his recent book, top climatologist James Hansen described “fast reactors“, which are a vast improvement over the previous generations of nuclear reactors. It’s also possible to use uranium-238 as fuel, which makes up 99.3% of all natural uranium, and is usually thrown away as nuclear waste because reactors aren’t equipped to use it. Another alternative is to use thorium, a safer and more common element. If we pursue these technologies, the major downsides of nuclear power – safety and waste concerns – could diminish substantially.

Renewable sources of energy, such as solar, wind, and geothermal, are safer than nuclear power, and also have a lower carbon footprint per kWh (Sovacool, 2008b, Table 8). They are clearly the ideal choice in the long run, but they can’t solve the problem completely, at least not yet. Cost is a barrier, as is the problem of storing and transporting the electricity they generate. Maybe a few decades down the line smart grids will become a reality, and we will be able to have an energy economy that is fully renewable. If we wait for that perfect situation before doing anything, though, we will overshoot and cause far more climate change than we can deal with.

I don’t know if I would describe myself as “pro-nuclear”, but I am definitely “anti-fossil-fuel”. I am aware of the risks nuclear power poses, and feel that, from a risk management perspective, it is still preferable to coal and oil by a long shot. Solving climate change will require a multi-faceted energy economy, and it would be foolish to rule out one viable option simply because it isn’t perfect.