Photo by Kyrylo Kalugin.

The “emissions gap” is the difference between “business-as-usual” greenhouse gas emissions, which continue to rise, and the level such emissions actually need to fall to in order to keep average global warming below 2 degrees C (3.6 degrees F) — the goal that was internationally agreed to at the Cancun climate talks in 2010.

To keep warming below that level, we’d have to have achieved a cut of 12 billion tonnes of greenhouse gas emissions by 2020. That’s the gap we must bridge.