GEOG 438W
Human Dimensions of Global Warming

The space between

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We need to think about mitigating greenhouse gases in 3 distinct phases:

  1. slowing emissions growth
  2. stabilizing emissions
  3. reducing emissions

Often, we talk generically about 'reducing emissions' and when we do, we're talking about reducing them from what they are right now. But in this context, we're talking about reducing them beyond the point of stabilization. We have a lot of work to do slowing emissions growth and stabilizing emissions before we can really dig into reducing them.

Each year, the UN puts out an Emissions Gap Report. Quite simply, the report shows us where we are vs. where we need to be (and how that has changed from year to year) and discusses ways to close that gap. Let's take a look.

Remember, the science tells us we want to contain warming to between 1.5-2 degrees Celsius. Those trajectories are shown in green and blue. What do you notice about how they align with projected emissions reductions under current Paris Agreement commitments (NDCs or nationally determined contributions)? The space between those scenarios is the emissions gap. Are you surprised or did you expect the gap to be this big (or this small depending on how you're looking at it)? Can we get there?  

Global GHGs under some scenarios from the UN and the 2030 emissions gap
Credit: Figure 3.1 from the UNEP Emissions Gap Report 2018 (Fair Use)

That gap looks a bit daunting, doesn't it?  But how are we doing?  Globally, we aren't on track to meet our 2030 goals under the Paris Agreement, and in early November 2019, the Trump Administration submitted its formal request to pull the US out of the agreement altogether (this process takes a full year, though, so depending on this November's election, perhaps the US won't end up leaving the agreement).

bar graph illustrating that the world's emissions projections suggest we will not achieve emissions reductions consistent with limiting warming to 1.5 degrees
This graphic illustrates projected emissions, despite Paris Agreement commitments and how these align with containing warming to 1.5 degrees C.
Click here for a text alternative to the image above

The world is not on track to limit temperature rise to 1.5ºC

Current Annual Emissions (2016): 52 GtCO2e

Where emissions are headed (2030): 52-58 GtCO2e

Emissions in 2030 consistent with 1.5ºC: 25-30 GtCO2​

Net-zero emissions consistent with 1.5ºC: 0 GtCO2​

Credit: The World is Not on Track to limit Temperature Rise to 1.5°C by the World Resources Institue is licensed under CC BY 4.0