The model does not predict much differences between the different scenarios until 2020-2030. Therefore, we only know that the model has not been falsified so far, but it is still unclear what the path is we are currently on.
I think it would be helpful to see an overlay of our actual trajectory. Though the absolute values of the models are not that different for the period 2000 to 2020, the slopes are quite different. I think there was a paper analyzing the fits including the slopes. The increase of production of food since the year 2000 has been much larger than any of the models predicted. Also, I think the increase in industrial capacity is higher than any of these models. Interestingly, some people interpret this as us overshooting farther, so then we will fall more dramatically. But because we generally have not seen reduction in slopes, I donāt really see evidence for this, so I think that the optimistic interpretation is more likely to be right, basically that we have innovated around limits to growth so far.
Thanks David. I think the paper you are referring to might be the one I cited. At least Herrington also looked at the rate of change as well (Table 2). There you can see that the current trajectory and rate of change is most similar to the CT and the BAU2 scenario. CT being a scenario like you described (we innovated ourselves out of limits to growth), while BAU2 being a scenario where we are still on a collapse trajectory, but the resources of Earth are 2x of the default limits to growth scenario. Therefore, I would argue that we still canāt tell if we just had more resources on Earth than originally estimated or if we solved our problem with innovation. But if you have another paper that discusses this as well, Iād be happy to read it.
Nice post!
I think it would be helpful to see an overlay of our actual trajectory. Though the absolute values of the models are not that different for the period 2000 to 2020, the slopes are quite different. I think there was a paper analyzing the fits including the slopes. The increase of production of food since the year 2000 has been much larger than any of the models predicted. Also, I think the increase in industrial capacity is higher than any of these models. Interestingly, some people interpret this as us overshooting farther, so then we will fall more dramatically. But because we generally have not seen reduction in slopes, I donāt really see evidence for this, so I think that the optimistic interpretation is more likely to be right, basically that we have innovated around limits to growth so far.
Thanks David. I think the paper you are referring to might be the one I cited. At least Herrington also looked at the rate of change as well (Table 2). There you can see that the current trajectory and rate of change is most similar to the CT and the BAU2 scenario. CT being a scenario like you described (we innovated ourselves out of limits to growth), while BAU2 being a scenario where we are still on a collapse trajectory, but the resources of Earth are 2x of the default limits to growth scenario. Therefore, I would argue that we still canāt tell if we just had more resources on Earth than originally estimated or if we solved our problem with innovation. But if you have another paper that discusses this as well, Iād be happy to read it.