What's a Carbon Budget?
To stabilise global temperatures to a target level there is a finite total amount of greenhouse gas emissions that can be released. This is referred to as a carbon budget.
Carbon budgets are FAR more useful than Net Zero by 20-whatever. Net Zero by 20-whatever can tend to give us a fuzzy nice feeling that everything is in hand, and that we've got ages to sort it out. That is simply not the case.
How can we see what our carbon budget is?
The Tyndall Carbon Budget tool lets you see the science-based carbon budgets that each UK local authority needs to adopt if we're to keep to the United Nations Paris Agreement.
Here is a link to the Tool:
https://carbonbudget.manchester.ac.uk
You can also make custom aggregate reports to see budgets for whole Counties.
More importantly - what do we need to do?
I've been making my own very rough graphs and they agree with the Tyndall tool - both point to yearly percentage reductions being absolutely vital.
They place that reduction at around 13.5% a year. My rough graphs do too - it's pretty simple really even if we don't much like seeing the result!
For the South Hams the total budget left is 4.5 Million tonnes of CO2eq.
The eq means "equivalent" - so this 4.5 million tonnes includes other greenhouse gases like nitrous oxide and methane which have a greater warming effect than CO2. They are converted to the equivalent amount of CO2 and added together to help us make sense of it.
How can we stay within Budget?
The graph above shows 3 possible pathways we could take in response to the scientific advice. To play our part in limiting warming to 1.5°C, cumulative emissions from 2020 must not cross the dotted line.
The lower purple line is the only one which does not go over-budget - and this represents a 13.5% reduction in greenhouse gas emissions every year.
The South Hams "spends" around 550,000 tonnes of CO2eq per year so that's our starting point.
Do nothing: our budget is spent sometime in 2028.
Reducing by the same amount each year: by 2030 the budget is spent.
Reduce by around 13% a year: we just stick within our budget.
This picture is very similar whether we're a Nation, County, Local Authority, Town, Parish, Business, or household - the logic is the same.
A year on year reduction of around 13% is the only approach that keeps to the budget, every other approach uses up our budget.