The U.N. Intergovernmental Panel on Climate Change (IPCC) has just issued its third of four planned reports. This one is on “mitigation” — “human intervention to reduce the sources or enhance the sinks of greenhouse gases.”
The first two reports laid out humanity’s choice as depicted in the figure above, which appeared in both reports. The first report warned that continued inaction would lead to 9°F warming (or higher) for most of the U.S. and Northern Hemisphere landmass, resulting in faster sea level rise, more extreme weather, and collapse of the permafrost sink, which would further accelerate warming. The second report warned that this in turn would lead to a “breakdown of food systems,” more violent conflicts, and ultimately threaten to make some currently habited and arable land virtually unlivable for parts of the year.
Now you might think it would be a no-brainer that humanity would be willing to pay a very high cost to avoid such catastrophes and achieve the low emission “2°C” (3.6°F) pathway in the left figure above (RCP2.6 — which is a total greenhouse gas level in 2100 equivalent to roughly 450 parts per million of CO2). But the third report finds that the “cost” of doing so is to reduce the median annual growth of consumption over this century by a mere 0.06%.
You read that right, the annual growth loss to preserve a livable climate is 0.06% — and that’s “relative to annualized consumption growth in the baseline that is between 1.6% and 3% per year.” So we’re talking annual growth of, say 2.24% rather than 2.30% to save billions and billions of people from needless suffering for decades if not centuries. As always, every word of the report was signed off on by every major government in the world.
Moreover, this does not even count the economic benefit of avoiding climate catastrophe. A few years ago, scientists calculated that benefit as having a net present value of $615 to $830 trillion. That means our current do-nothing plan is actually far, far costlier than aggressive climate mitigation.