By 2030, the population of Ukraine (including the residents of Crimea) may shrink to 40.88 million people. In 2040 it could make 38 million; in 2050 - 35.22, which is about one-fifth of the current population of Ukraine. By 2100, this number may reduce to 24.4 million people. This is mentioned in the UN World Population Prospects report.
Ukraine, Bulgaria, Latvia, Lithuania, Wallis and Futuna Islands are expected to experience the largest cutdown of the population - by 20 percent, in all cases. However, Ukraine is to feel the effect of the inflow of migrants during that decade, which could ease the negative index of the natural growth of the population.
In general, the report says that the world’s population is expected to increase by 2 billion persons in the next 30 years, from 7.7 billion currently to 9.7 billion in 2050.
By 2027, China is expected to lose to India as the world's most populous country. However, the global fertility rate, which fell from 3.2 births per woman in 1990 to 2.5 in 2019, is projected to decline further to 2.2 in 2050.
As far as the population's aging is concerned, in 2050, every sixth person on the planet would be older than 65; currently, it is every eleventh person on the globe.
The average lifespan is expected to grow - in rich and developed countries; on the other hand, it is to drop in the poor countries - due to high epidemic rates and violence rates.