There is no carbon budget left for 1.5°C climate warming target, which means that to achieve this outcome every tonne of emissions must be matched by a tonne of drawdown of atmospheric carbon from now on. For that reason, carbon budgets and emissions target should be complemented by a carbon drawdown budget and target.
That’s the proposal made by Breakthrough, the Melbourne-based National Centre for Climate Restoration, to the Victorian climate change targets 2021-2030 expert panel, last week.
In the submission, Breakthrough established that:
- 1.5°C of climate warming is not safe;
- There is no carbon budget remaining for 1.5°C, so “What goes up must come down”;
- “Overshoot” in emission reduction scenarios should be minimised in extent and duration to avoid tipping points that may be irreversible on human time-frames.
Here’s the story in more detail.
1. 1.5°C of climate warming is not safe
The Paris Agreement has a policy goal of 1.5–2°C, but even 1.5°C is far from safe and is not a satisfactory target:
- In 2015, researchers looked at the damage to system elements — including water security, staple crops, land, coral reefs, vegetation and UNESCO World Heritage sites — as the temperature increases. They found all the damage from climate change to vulnerable categories like coral reefs, freshwater availability and plant life could happen before 2°C warming is reached, and much of it before 1.5°C warming.
- In 2013, Australian scientists contributed to an important research paper which found that preserving more than 10% of coral reefs worldwide would require limiting warming to below 1.5°C. Recent research found that the surge in ocean warming around the Great Barrier Reef in 2016-17, which led to the loss of half of the 2015 reef area, has a 31% probability of occuring in any year at just the current level of warming.
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