Most European nations have fairly weak dygenics, with the only outliers being Southeatern European countries like Romania and Macedonia. The United States has relatively strong dysgenics, with a projected decline of .4 points per decade. If the low quality datasets are ignored and only the NLSY79 is considered (best dataset due to high quality testing, large nat-representative sample, and completed biological fertility measurement), this decline rises to .46 points per decade. These figures were adjusted based on the fact that some datasets have weaker dysgenics than others. If that adjustment is not made, then the future looks even less bleak for Europe - most countries are expected to have declines of .1 to .2 points due to differential fertility.
As for immigration, it is possible to predict the effect of changes in racial demographics on the national IQ of the United States if the averages of each racial group are known. Based on projections from the US Census, the national IQ of the United States will fall by 0.5 points due to changes in racial composition, and 1.5 points due to dysgenic fertility in the next 40 years.
Unfortunately, Europe is not going to be so lucky. Typically, immigrants who move to Europe are less selected for educational attainment than the ones that move to America. In addition, they are more likely to come from less developed, such as Africa or MENA, while American immigrants are more likely to come from Asia or Latin America.
Because of this, the effect of immigration on human capital and intelligence will be should be more drastic in Europe than America. Unfortunately, I cannot do as precise forecasts for the European nations as the data is limited, but if native Swedes are assumed to have an IQ of 100, and Swedish Arabs are assumed to have an IQ of 85, then the decline from 2015 to 2065 should be about 3 points in total - six times worse than the decline that is observed in America.
(National IQ of Sweden in 2015 was estimated to be (100*0.95+85*0.05) = 99.25, for 2065 it was assumed to be (100*0.75+85*0.25) = 96.25)
The whole first paragraph is missing 0. Infront of every IQ decline number.
Great post but could you factor in the effect of mutational load and negative flynn effect? Also sweden is a bad example as it doesn’t have 2012-14 immigration levels anymore and actively deports non white back. Becoming 0.4% more white each year