So...what is the cost of reducing global temperatures by a measly one-fourth of one degree?
Well, as can be seen in the adjacent image, it's a ludicrously gargantuan cost for maybe, a tiny, and barely measurable global temperature benefit.
What's the cost of reducing global temperatures to their 1850 level? Go to this simple estimator and enter '0.85' in the second third (from top) yellow box (cell). That will produce a rough estimate of how much it would cost in today's dollars using available technology means.
This simple cost estimator is based on the actual HadCRUT4 annual global temperatures and estimates of historical CO2 emission tons. By knowing this basic information, it is possible to calculate (using plain arithmetic) an approximate value for an increase in temperature caused by a single tonne of CO2.
Indeed, nothing fancy. But it does the job well enough to allow further estimations as to how many CO2 tonnes it takes to change global temperature a specific amount. Then it's just a matter of multiplying all those tonnes (billions to trillions) by a dollar cost/tonne.
With that explained, this estimator allows for two different cost scenarios associated with different approaches to future CO2 reduction.
One method of reduction requires the actual removal of CO2 from the atmosphere, which still appears to be far from viable, either economically and technically - read more here. The cost of this approach is not really known, thus 'C3' used a figure of $500/CO2 tonne, which can easily be changed in the estimator tool.
The other method of reduction is future CO2 emission avoidance. This method is typified by making buildings and vehicles more energy efficient; using renewable energy sources; and/or using natural gas and nuclear instead of coal. We used a figure of $75/tonne that is likely too low, but it also can easily be changed when using the estimator.
By playing with this estimation tool, it quickly makes one aware of those truly stubborn climate facts: regardless of the politics of global warming, the economic and technical costs of lowering future global temperatures are astronomical for producing such a measly impact - ie, benefit.