According to the government\’s National Ecosystem Assessment, looking after all the UK\’s green spaces is worth the sum of £30bn a year to the economy.
The whole process becomes even more meaningless when you try to compare the £30bn figure with other economic statistics. Take the UK government\’s national debt, which at the end of last year was more than £1,105bn or more than 36 times the value credited to our green spaces.
Ah, I see the problem here. It\’s that you, Nicholas Milton, are a cretin.
The national debt is a stock. It\’s the total of all the money we\’ve ever, as a nation, borrowed and not paid back.
The £30 billion of the green spaces is the annual income: it\’s a flow. If we wish to compare this to the national debt we must convert this income to a stock: good, we know how to do this, this is a net present value calculation. Err, OK, some people know how to do this, I don\’t.
We need to be a bit leery about discount rates. Market rates on something so long term probably aren\’t quite right. Mebbe 2 or 3 % would be about right.
This would give us the capital value of that income flow, which is something that we can then compare with the national debt.
At a guess (if anyone wants to run the numbers?) I\’d say that at such a suitably low interest rate, the value of the green spaces is higher than the national debt.