Many scientists and activists have stated, with good reason, that the 2007 IPCC 4th Assessment Report (4AR) didn’t look deeply enough into the potential costs of doing nothing to change the globe’s GHG emissions. The good news is that in addition to developing a more robust research methodology to dig into the unknowns of the science surrounding climate change, work has also taken place to assign realistic figures of the costs of adapting to climate change. The figures available for the past few years were viewed as having major shortcomings: unrealistic assumptions, not accounting for enough of the effects (which have interdependencies and feedbacks of their own), etc.
A new study was issued earlier this month by the International Institute for Environment and Development (IIED) that worked to address some of those concerns. For reference, I’m going to discuss the Section 8 material. It is not without its own set of caveats and disadvantages: it looks at the IPCC A2 scenario, for instance, even though our actual emissions have already outpaced this mid-range emissions scenario. There’s another equally out-dated caveat that I’ll talk about more below. So, take the results with a grain of salt – realize that these costs continue to be an underestimate of what we’re likely to face!
With that in mind, what are some of the results of this study? Without adaptation, the mean net present value of climate change impacts under the A2 scenario is $1240 Trillion.