Much has been written, although not all that well publicized, about the total cost to convert the planet to 100% renewable energy – $100 Trillion, in case you were wondering – and those of us who have been well acquainted with the “2 Degree” target that we have to globally hit to prevent the very worst of the effects of climate change, however one number that I have had trouble finding explicitly, what is the dollar figure we need to invest, globally, to keep the planet below that 2 degree threshold. Spending some early morning reading time googling, I’ve come across two good references.
The first I found while catching up on my renewable energy securitization reading and was buried in an old article from June 2011 in Renewable Energy Magazine Online. The author of the article Financing Renewable Energy – A Securitization Approach John Joshi quoted, yet failed to foot note or link to The International Energy Agency’s estimate of $10.3 trillion. I would love to find the original article from the IEA and will look for it – however my gut tells me that the $10.3 trillion figure is probably about right.
The second source was at Think Progress, It’s Not Too Late To Stop Climate Change, And It’ll Be Super-Cheap, by Joe Romm. The estimate Romm gives is as a percentage of global GDP and puts it at 1%, quoting from an 2014 IEA report “Energy Technology Perspectives”. Romm’s original link is dead, but the IEA report is available for purchase and download.
I won’t go in to a detailed analysis of how they arrived at their numbers, I’m going to take for what its worth that the IEA has remained relatively consistent over time and is more well informed than I am. Comparing the two estimates though we can arrive at a reasonable estimate. Depending upon which GDP numbers you want to use, the annual dollar figure would come out to be between $650 million and $750 million. Josh’s number doesn’t give an annual progress limit to be reached, but over a ten year time frame, that $1 trillion annually, over 20 years $500 billion. Either way you slice it, on a global scale, these numbers are a relative drop in the bucket.