A Thermostat for the Earth

Modern houses are remarkably comfortable. Despite huge fluctuations in outside temperatures, they manage to keep a pleasant temperature inside. The reason for this is an invention called the thermostat, which measures the temperature in the house and compares it with the desired value. If it is too cold, it turns the heat on. Otherwise, it turns it off.

A thermostat is just one example of a control system providing a simple solution to a difficult problem. The general idea is illustrated in the figure below. The black box represents the house, which is actually a very complex physical system. The required heating depends on the outside temperature, wind speed, cloud cover, the number of people inside, how often the doors are being opened, and a number of other factors. It is simply not possible to predict how much heat is going to be required in advance. The control system solves this problem by measuring the actual temperature and providing feedback to the heating system. It suddenly becomes possible to control the temperature without detailed knowledge of the black box.


The Earth’s climate and the global economy are both very complex system. Anyone who believes that we can understand them in detail in order to be able to calculate the optimal response to global warming is delusional. It therefore makes no sense to compare the “cost” of preventing global warming to “economic damage” resulting from climate change, as we can compute neither of the two with reasonable accuracy. We are therefore suffering from paralysis by analysis: We refuse to act because we believe that we do not have sufficient information. The problem is that we will never have enough information.

What we do know for certain, however, is that continuing CO2 emissions will lead to higher temperatures. We also know that the most efficient way to regulate these emissions is through carbon pricing or a carbon tax. An automatic taxing mechanism, as proposed by GISEco, would work like the thermostat in the house and adjust the tax level to produce the correct output for the climate and the global economy. The principle is illustrated below:


The beauty of this concept is that it is effective, easy to implement, and risk free. Everyone agrees that a simple carbon tax is the most efficient way to control CO2 emissions. The administrative effort to introduce the tax is very low and it can easily be adjusted to provide the right outcome for society. Furthermore, it would make every human on the planet part of the solution: We all dislike paying taxes and could do so by reducing our energy consumption. To argue that such a system would not work is like denying the existence of thermostats.

The climate of the Earth has now entered unchartered territory. The last time it was this hot was probably 100,000 years ago and modern humans had not yet left Africa. In fact, we have allowed the situation to deteriorate so far that the survival of humanity seems to depend on future generations inventing some hitherto unknown carbon capture mechanism, despite the fact that this violates the second law of thermodynamics (please send me an e-mail if this is unclear).


We know that that our current approach of dealing with climate change through non-binding international agreements does not work. We also understand why this is so and what would actually be required to stop global warming. A global carbon tax would remove most of the uncertainties for investors and politicians, forcing them to take action. Opposing it makes about as much sense as trying to design a good heating system for a house while opposing thermostats on ideological grounds.

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