Kotz, Levermann and Wenz suggest that this is an indication of the warming we are already committed to, partly because the effect of past emissions has not been fully felt and partly because the global economy is a slowly turning ship. so it will take time to implement significant changes in emissions. “Such a focus on the short term limits large uncertainties about divergent future emissions trajectories, the resulting long-term climate response, and the validity of applying historically observed climate-economic relationships over long periods of time during which sociotechnical conditions They can change considerably.” they argue.
Unequal costs
So what will happen in 2050? The researchers’ model suggests that “the damage committed includes a permanent reduction in income of 19 percent on average globally,” compared to what growth would have taken us. The uncertainties mean the likely range is between 11 and 29 percent. Using an intermediate scenario for economic growth, this translates into an economic hit of $38 trillion (a figure measured in international dollars).
The authors contrast this with an estimate by the IPCC of the costs of limiting warming to 2 degrees Celsius: $6 trillion. Therefore, even the short-term impacts of climate change will far outweigh the costs of action.
This blow is not distributed evenly. Wealthy parts of the United States and Europe will see their incomes fall by only about 11 percent, while Africa and South Asia will take a hit of 22 percent. This is probably because rich countries already have a greater capacity to adapt to climate-related problems than those in the Global South. But it is also surprising, since the pace of change is much greater outside the tropics, so these countries will also face more extreme changes. Researchers see areas experiencing economic benefits, but they are limited to the high latitudes closest to the poles.
Kotz, Levermann and Wenz note that areas with the highest costs tend to have the lowest cumulative emissions. In other words, the problems are felt most intensely in the countries that made the least contributions to them.
There are also some effects that are beneficial. Areas that experience an increase in average rainfall see income increase due to that effect (although drier areas experience the opposite). But these same areas see additional costs due to the increase in the average number of rainy days that largely offset this effect. And the impact of more extreme precipitation is negative everywhere.
It could be worse
There are a couple of ways this could end up being an underestimate of future costs. In the long term, a continually warming climate will begin to produce more historically unprecedented events, meaning there is no way to project their economic impact. By limiting the analysis to about 25 years, the researchers make it less likely to be a major factor. But unprecedented events are already happening, so we are already at a point where some problems are underestimated.
There are also a large number of climate events that are not considered at all, including heat waves, severe tropical storms, and sea level rise. Individually, any of these events are unlikely to show dramatic changes over the next 25 years, but the cumulative impact of gradual changes will not be included. Additionally, there is always the possibility of reaching a tipping point where a sudden change in the frequency of one or more of these events occurs.
Finally, researchers don’t really consider non-local impacts, such as when extreme weather in one place can disrupt supply chains and produce impacts elsewhere. Let’s think about cases in which large urban centers import a large part of their food from relatively distant places.
Kotz, Levermann, and Wenz acknowledge all of these issues, but suggest that their more conservative empirical approach provides some clarity that is difficult to achieve otherwise.
However, one aspect that they do not consider has to do with the comparison between the costs of the damages committed and the cost of decarbonizing the economy. Over the past 20 years, the price of mitigating climate change through renewable energy and efficiency has plummeted dramatically, and the price of other key technologies, such as batteries, is following a similar trajectory. By 2050, this could make the difference between the cost of acting and the cost of doing nothing even more dramatic.
This story originally appeared on Ars Technique.