Don’t mention the solar panels

On a flight this morning I began to think that the Bjorn Lomborg quote I heard yesterday couldn’t be plausible:

Germany once prided itself on being the “photovoltaic world champion”, doling out generous subsidies – totaling more than $130 billion to citizens to invest in solar energy…by the end of the century, this will have postponed climate change temperature increases by 23 hours.

So I tried a quick back of the envelope calculation:

German population = 70m

Global population = 7bn

Ratio = 1/100

Number of years solar panels last for = 20

Years over which CO2 emissions have and will accumulate before the bad temperature rise (say 2100 – 1900) = 200

Ratio = 1/10

Reduction in CO2 emissions of Germany = 1/100 (the article gives a less than 1% current total supply by solar)

Germany’s level of emissions during these 20 periods relative to global average over 200 years = x2

Total portion of CO2 from global total that will be avoided =(1/100) x (1/10) x (1/100) x 2 = 2/100,000

Number of days over which CO2 emissions occur = 365 * 200 = 70,000ish

Over 1m Germans have solar panels installed. Number of days of CO2 emissions avoided from these, i.e., how much extra time is bought before a catastrophic temperature increase  = 70,000 x 2 / 100,000 = 1.4 days

Wow. Well done. I definitely feel less bad about my flight now. Not that I was.

I came across Without Hot Air several years ago and found it to be very credible – same approach, back of the envelope physics…I seem to have just complimented myself on being very credible. I’d best stop myself here. It’s not impossible I’ve missed something obvious out of the above…

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