We hear the words 'Net Zero' endlessly. But how many tonnes of greenhouse gases does that actually mean? The answer is surprisingly tricky to find.
Let's focus on 2030 targets for now. Australia has committed to reducing greenhouse gas emissions to 43% below 2005 levels by 2030. Eh?
We've done the maths and found that means 351.3 million tonnes of carbon dioxide equivalent (CO2-e)* in a year. In the previous year, Australia released 462.6 million.
What's beneath the curve?
To answer that, we're going to use a different data source. The chart above uses quarterly emissions updates. If we use annual data, we can look back further.
Here is Australia's emissions curve since 1990. It's clear that Land Use (highlighted red) is doing the heavy lifting for Australia's emissions reductions.
What is Land Use? It's shorthand for Land use, land-use change, and forestry (LULUCF). It tries to measure how much greenhouse gas is removed from the atmosphere by trees, vegetation and soil.
LULUCF data is controversial. Methodologies and estimates vary wildly, not only between datasets, but within them, leading to fluctuations and revisions between years.
If we put Land Use at the top of the curve and group the other sectors together, we get a clearer picture of Australia's emission reductions. Follow the black line, which shows Australia's emissions excluding LULUCF.
Data reporters are grappling with this in different ways.
- The German government-funded Potsdam Institute for Climate Impact Research has excluded LULUCF altogether, saying it is unreliable and misleading.
- New Zealand reports emissions excluding LULUCF, which it calls 'gross emissions' as opposed to 'net'.
- The Guardian Australia's climate progress tracker has a toggle to include or exclude LULUCF.
OnlyFacts will be grappling with it as well, as we try our best to communicate the facts without inundating you. Do you want to see emissions including and excluding LULUCF? Let us know.
* Data note: CO2-e = Carbon Dioxide equivalent. This means all Greenhouse Gases are given a value in CO2, based on their global warming potential.