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Strange goings-on at the Committee on Climate Change

Back in May, readers may recall, the Committee on Climate Change put the annual cost of decarbonising the economy at “1-2% of GDP in 2050”. Subsequently I determined that this figure is actually not the cost (how much would have to be spent) but instead “how much worse off we would be” (the costs less the benefits). The report contained a graph (Fig 2.5) giving a breakdown of the annual cost by sector, but apart from that there was little information about how the figures had been arrived at.

On 13 June I asked the CCC for the underlying calculations. Tom, the FOI officer, was very forthcoming, and over the next two days he pointed me to lots of places in the Net Zero report where I could see words about the numbers, but sadly nothing he indicated amounted to “calculations”. As I pressed him, he became bashful, and on the afternoon of the 14th he went quiet. Finally, on 19th June he said that they were working on a response.

A few days ago, I received my reply, directing me to the Net-Zero costs dataset, a spreadsheet containing a breakdown of the sectoral totals by policy action. For each line there were three figures

  • the marginal abatement cost (£/tCO2)
  • the extent of the abatement (tCO2)
  • the cost, being the product of the previous two columns.

The final column seems to add to the correct total, namely £49.5 billion per year, so, to that extent, the dataset adds to the sum of our knowledge. However, in terms of understanding whether the estimates are reasonable or not, it’s frankly fairly useless. Where have the marginal abatement costs come from? The notes to the spreadsheet say they are estimated by:

“…adding up the capital and operating costs over the lifetime of the measure and subtracting the capital and operating costs of technologies and behaviours in a world without climate action, and spreading this difference in costs across the emissions savings over the lifetime of the measure.”

I’ve therefore requested further information to allow me to see and understand these calculations.

However, in passing I noted a rather amusing feature of the spreadsheet. Take a look at the file properties:

According to this, this dataset was only created on 19 June, the very day that Tom had reemerged to tell me that the CCC was “working on” a response. That’s fully six weeks after the publication of the Net Zero report. It looks as if the dataset was prepared just for me. It’s very kind of them, but what, then, had the CCC been using prior to the report’s publication?

I’m also interested that the spreadsheet was authored by someone at DEFRA. The CCC is of course “independent” of government. Ms Letti certainly claims on her LinkedIn page to be working for the CCC. So why does her wordprocessor think she works for DEFRA?

It’s all rather strange.