Thanks to Mark for ably dissecting this absurd piece of (proposed) legislation, and for linking to its supporters. I was relieved to see that my MP is not – yet – on the list of supporters, for otherwise I would have been compelled to send her a pointless missive registering my opposition.

However, I was disappointed to see some 1,200 academics on the list, including assorted Very Smart™ professors and PhDs.

The provisions of the bill are impossible to achieve. That should be obvious to anyone given a cursory glance at a mite of data. On the presumption that the cream of UK’s Ivory Tower Corps have not done so, I’m laying it out here.

The key matter as regards the UK’s CO₂ emissions that concerns us here is the SoS’s duty in

…limiting the United Kingdom’s total emissions of carbon dioxide to no more than its proportionate share of the remaining global carbon budget

in 2 (3) (a) of the bill.

It is also ordered that imports of CO₂ (as embodied in goods and their production) must decline at the same percentage rate.

The bill gives the remaining Global Carbon Budget as 400 Gt CO₂. It covers the period 2020-2050, and on my reading, we have already used up part of our share of the budget in the 5 years between 2020 and 2024.

Here come the numbers

The UK’s population is 0.85% of the Earth’s, giving us a share of the GCB of 0.0085*400 Gt CO₂, or

3.4 Gt CO₂

in total from 2020 to forever.

Our usage between 2020 and 2024, with a placeholder value of 300 Mt CO₂ for 2024, is

1.528 Gt CO₂

[This value is the sum of our emissions, from EDGAR, of years 2020-2023 {319, 339, 327, 302 Mt}, with that 300 for 2024. Yes. We have used up nearly half our allowance in 5 years.]

The UK’s remaining allowance is 3.4 – 1.528 =

1.872 Gt CO₂

Now, allowing for a linear decrease in CO₂ emissions, the length of time remaining to us (showing emissions as Mt for simplicity, and calling the baseline value 300 Mt/yr) is equal to (1872 * 2) / 300 years, or

12.5 years

Giving us until June 2037 to reach the hallowed Net Zero.

***This includes zero imports with any carbon footprint.***

The slope of the required reduction, i.e. the saving per year, is easy to calculate as 300 / 12.5. The answer is a net change of

– 24 Mt CO₂ / year

In the first year, this is a modest (!) – 8%. Naturally, the way percentages work, it ramps up rapidly as the amount emitted per year ramps, er, down. By 2028, we have to make a 10% saving on the previous year. By 2031, it’s 15% per year.

What about a constant % reduction each year, giving an exponential decline? Well, this is more difficult to calculate, because by their nature, such curves never hit zero. Very roughly the required annual cut would be 15%, but as noted, it would never reach zero. A 15% cut per year would see us using about 1800 Mt CO₂ of our 1872 Mt allocation by 2050. (At 14% cut per year, we would be well over our total allocation by the mid-2040s.)

The (minor) beneficial effect should we reset the baseline…

According to globalcarbonbudget.org, the remaining budget from 2025 onwards is 235 Gt CO₂. The UK’s share given 0.85% population is 2 Gt CO₂; applying the same reasoning as before, t = (2000 * 2) / 300 or 13.3 years, giving us until April 2038 to reach Net Zero.

How do you find 1200 smart academics willing to sign up in support of a bill so unutterably stupid?

Well, there are a number of reasons why such folk might sign. My interpretation of the possible reasons, in descending likelihood:

1) they have not read the bill, and see an easy demonstration of virtue in signing up to support it

2) they have read the bill, but have not bothered to try to understand the consequences were it to be enacted, and see an easy demonstration of virtue in signing up to support it.

3) they have read the bill, and understood its implications, and see an easy demonstration of virtue in signing up to support it, knowing that it will never come into law.

4) they have read the bill, et cetera, and though they believe that there is a good chance it will become law, they reassure themselves that its impossible nature will end up preventing its worst possible effects coming to pass; in other words, the inevitable failure to reach the stated goals, & associated chaos, still results in a net benefit, by hurrying us along the Net Zero path, by law.

5) they see themselves as exempt from the devastation the bill would imply, and wish to study the rats the size of cats that will roam our deserted cities, post apocalypse.

6) we are living in Clown World.