Why would Canada support the 1.5 C temperature target?

On Monday at the UN Climate Summit in Paris, Canada made a decision that shocked and confused many in the policy world.

Environment Minister Catherine McKenna stated that Canada backs the idea of eventually limiting global warming to less than 1.5 °C above pre-industrial levels. This lower temperature limit is advocated by many developing countries, including low-lying small island states like Kiribati, the Marshall Islands, and Tuvalu.


From a numbers standpoint, Canada’s new position may look crazy. The lower temperature target appears, practically speaking, next to impossible to achieve.

The world is currently far off the pace to stay within the existing 2 °C limit agreed upon by most of the major world economies, including our neighbour to the south. If you add up all of the emissions reduction pledges made by the different countries meeting in Paris, the world is on pace to warm by as much as 3.5 °C or more.

To have a good chance of staying within the 1.5 °C limit, the world can only emit another 270 gigatons of carbon dioxide. At the current rate of emissions, we’ll blow that entire bank in less than a decade. Then, the only way to keep within the target will be to rely on what scientists call “negative emissions” – to suck carbon dioxide out of the air, using technologies that either do not yet exist, are unproven, or have never been implemented at large-scale.

Is this yet another case of Canada’s rhetoric on climate action being unmoored from the reality of greenhouse gas emissions?

In fact, the decision is about respect. In pushing to include reference to a 1.5 °C limit, Canada is saying that the people of small island developing states and vulnerable countries like Bangladesh matter.

Despite what you’ve probably heard, the popular 2 °C target is not dictated by science. The 2 °C target is a political decision made largely by the developed countries – the same countries that are most responsible for climate change.

The fact is that there is no scientifically definable “safe” amount of climate change. Science can provide us with a guide to the impacts of different levels of warming. The amount of warming we deem as “safe,” however, depends on our values and our perception of risk.

If you live in a small island nation in the tropics, more than 1.5 °C – not 2 °C – of global warming certainly seems dangerous.

For example, with more than 1 m of sea-level rise, around 90% of countries like Tuvalu, the Marshall Islands, and Kiribati could become so prone to flooding as to be uninhabitable. While there’s large uncertainty about the rate of future sea-level rise, evidence from the distant past suggests the risk of losing the major ice sheets increases sharply with more than 1.5 °C of warming.

IMG_0253There’s arguably even greater concern among larger island countries like Fiji about coral reefs, a key source of food, income, and coastal protection in small island countries. The world’s coral reefs are already in trouble due to warming and acidifying ocean waters. If warming can be kept to less than 1.5 °C, two-thirds of the world’s coral reefs could be spared from serious degradation this century. With 2 °C or more of warming, reefs covered with living corals may become a thing of the past.

If you live in a small island nation in the tropics with historically low greenhouse gas emissions, there is a colonial air to the 2 °C limit. The rich countries are controlling your fate – through climate policy – and not even listening to your input.

Canada may look hypocritical in backing a 1.5 °C limit but not promising greater reductions in greenhouse gas emissions. However, the move has the potential to be more than mere tokenism and false hope.

Including the lower limit in the climate deal is a way of officially recognizing the harm likely to come to these more vulnerable countries. It will help ensure that these countries receive the needed international assistance, including terms of financing, investment in adaptation, and migration programs, which they have been promised through the UN system but has been slow to materialize.

6 thoughts on “Why would Canada support the 1.5 C temperature target?

  1. There are certainly historical reasons to be cynical about Canada’s decision; Canada has a poor record of meeting climate targets. I can’t say whether Canada’s decision was the right one. This post is simply offering a logical motive for making that decision, drawing from the perspective of the small island nations.

  2. A way to limit a global temperature rise to 1.5 C is to cut fossil fuel emissions as rapidly as possible to as low a level as possible while compensating for the overshoot of the forces warming the planet with geoengineering.

    Too high of an atmospheric concentration of GHG, and the quick decline in tropospheric aerosol that would result as fossil fuel burning was rapidly curtailed could be offset by temporarily introducing some sort of replacement aerosol into the stratosphere. I.e. the dreaded, some say “barking mad” geoengineering. If civilization was unified that it faced an existential threat demanding its best effort such a plan seems quite possible. Aiming to reduce the concentration of CO2 to below 400 ppm begins to address ocean acidifcation as well.

    I’d like to hear more representatives from developed countries talk like this.

    It will be interesting to see what this Trudeau government does in the coming years to live up to talk like this.

  3. If I were a citizen of a low-lying Pacific Island, I too would want to see a 1.5 degrees officially acknowledged as a limit beyond which great harm could be done to my homeland, including obliteration in some cases. It’s an admission, in effect, that the major countries of the world were heedless of the damage they have done.

    But given the inertia of our economies, it’s a bit like saying let’s lower the speed limit, just before the crash occurs.

    What distresses me about Canada’s government setting such a limit is that we don’t even have the national or provincial-level policies in place to reach the 2 degree limit, let alone 1.5. The federal Liberals have a long record of talking big on climate and doing nothing. I have high hopes for the Trudeau government, but this looks like more of the same.

    To be sure, these targets are political rather than technical, but they ought, at least, to be informed by science as to what is achievable. Either McKenna is getting bad expert advice, or she’s ignoring it for political reasons. That has unfortunate echoes of the set of rascals we just threw out.

  4. Technically, the Paris talks have bambozzled everyone about 1.5C and 2.0C actually means.

    It is not an accumulated Carbon emission target, it is a CO2equivalent ppm = X.XC temperature rise target.

    +1.5C = 400 ppm CO2equivalent; and,
    +2.0C = 450 ppm CO2equivalent.

    The only way to get to 400 ppm CO2e is to cut emissions by 55% tomorrow (we blew past 400 ppm CO2e about 3 years ago but if we cut emissions by 55%, CO2 would stabilize immediately and then slowly decline to the 400 ppm level).

    We could do that if we cut off electricity to the whole world tomorrow. That is what signing on the bottom line implies.

    The 2.0C limit is not much different.

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