Economic growth: more costly disasters, better prevention

If you read lists of the most costly earthquakes, hurricanes, and other natural disasters, you will find that they they tend to be quite recent, with damages increasing over time. But earthquake costs have not been rising because of some geological phenomenon, i.e. earthquakes getting more frequent or higher on the Richter scale. Rather, populations and economies have been growing, so that there are more valuable things for earthquakes to destroy. This dynamic offers a powerful defense against global catastrophic risks that can be addressed by interventions with particular fixed or falling costs.

Utilitarianism might imply that reducing existential risk for the sake of future generations should be the top priority of the current generation, but in practice action is more often mobilized by the interests of current people in accordance with their wealth and influence.

From a utilitarian point of view the primary cost of an asteroid extinguishing humanity is vast astronomical waste, with the losses of the current generation a rounding error by comparison. However, the financial losses to current people, those who might invest in countermeasures, will roughly scale with growth in world GDP: if economic growth continues the cost of a large asteroid impact will increase manyfold, even setting aside the distant future. On the other hand as the technology for detecting and deflecting asteroids advances it becomes cheaper. Per capita economic growth likely means higher labor costs, but still the costs of action should grow much less slowly than world GDP and the costs of an impact, providing increasing support for countermeasures. 

Similar processes have already led rich societies to make incredible expenditures on various forms of health and safety (by past standards) as incomes rose, while life remains relatively cheap in poorer countries. So, for natural disasters that can be addressed with fixed-cost interventions, the long run picture looks good. People who were especially concerned with these risks, like utilitarians who cared about future generations and were not deterred by public good problems, could speed up the countermeasures and acquire their protection for some years prior to their cost-effectiveness by conventional standards, but present-focused contractarian motivations would eventually suffice.

Unfortunately, more probable existential and catastrophic risks are anthropogenic ones, for which the costs of mitigation may increase as fast or faster than GDP. The capacity to construct nuclear weapons, engineered diseases, or harmful AI systems increases with progress. Efforts to regulate the most destructive technologies that slow advances will have costs related to the value of those sectors. Arms control efforts can involve concern with the security of one's society and all its increased wealth. Nonetheless, one-time beneficial expenditures will profit from economic growth, and the limited "window of risk" for most natural dangers is good news.