The nations of the world agreed in Paris (December, 2015) to pursue efforts to limit global warming to 1.5°C.¹ Canada pushed hard for the 1.5°C target, which will require gradually eliminating greenhouse gas emissions worldwide. The target has significant implications for both the production and consumption of fossil fuels.

In this post I review some important findings from science and discuss the implications for domestic policy. I find that if Canada is to do its part to fight climate change, then we likely cannot build new pipelines nor further expand Alberta’s oilsands.

The Science

How much the planet warms depends crucially on our future use of fossil fuels such as coal, oil and gas. Burning fossil fuels releases carbon dioxide (CO₂), the main greenhouse gas driving changing climate, into the atmosphere.

In its 2014 AR5 WGI report, the Intergovernmental Panel on Climate Change (IPCC) considered a range of possible greenhouse gas emissions scenarios. Two of the scenarios are given in Figure 1, which shows historical emissions up to 2005 and modelled emissions – based upon two possible futures – thereafter.²

The “business as usual” scenario (red line) has unabated fossil fuel usage, with emissions growing year after year as the demand for energy rises. The “significant reductions” scenario (blue line) has emissions peaking in 2018 and dropping to zero by 2070. Scenarios in between are also possible, and were explored by the IPCC.

The projected accumulation of greenhouse gases in the atmosphere is determined using Earth System Models (ESMs), which are comprehensive climate simulations run on the world’s fastest supercomputers. The results for both emissions scenarios are given in Figure 2. For business as usual the CO₂ concentration rises exponentially. For significant reductions the CO₂ concentration peaks at about 445 ppm in 2050 and declines thereafter owing to carbon cycling.

The warming projections associated with each CO₂ concentration pathway are given in Fig. 3. For business as usual, the global average temperatures increase to almost 5°C in 2100 (and continue to increase thereafter). For significant reductions, the temperature stabilizes at 1.6°C total warming.³

Analysis

Although the IPCC did not explicitly investigate a 1.5°C warming scenario, the 1.6°C result is close enough that we can use it to draw some conclusions. The simulations indicate if we hope to limit global warming to 1.5°C then greenhouse gas emissions must peak and start falling over the next few years. Since production is intimately connected to emissions – whatever is produced gets used – fossil fuel production must also be reduced. There is no other way.

The inescapable conclusion, as journalist Stephen Leahy has pointed out, is that from this point forward we cannot build any new fossil fuel infrastructure. Retired projects can be replaced, but only if the net production of fossil fuels decreases. New pipeline projects like Energy East can’t be built unless infrastructure somewhere else is eliminated. We must – if our words in Paris are to mean anything – begin the long process of drawing down and ultimately eliminating oil production, including in the oilsands. Doing otherwise would be to bet on something closer to the “business as usual” world, resulting in dangerous climate change.

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1. It was agreed in Article 2 of the Paris Agreement that the nations of the world should “[Hold] the increase in the global average temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change.”↩

2. One sigma uncertainties are shaded. There are uncertainties because the starting point for the models are actually the CO₂ concentration pathways, described next.↩

3. 1.6 sigma uncertainties, corresponding to the 90% confidence interval, are shaded.↩