The amount of square miles of land occupied by all of Europe in comparison to China is about the same, with Europe having about 6% more land than China in square miles. In regards to the population between China and Europe, in 1950, the population of both areas was also about the same with China having a small edge in population of 554,419,268 peoples in comparison to Europe's 549,328,858. It is estimated that in 2020, China's population as reported by worldometers.info is 1,439,323,776; whereas Europe's population is 747,636,026, or a near doubling of peoples in China as in comparison to Europe.
When it comes to the per capita gross domestic product (GDP) of China in 1950, this was just a paltry $614; whereas France's GDP in 1950 was $5,221 or more than eight times the amount of China. However, in 2018, China's per capita GDP had increased to $9,580, in comparison to France, which though much higher at $42,953 was now just four and a half times the amount of China. In aggregate, however, all of Europe has a GDP as of 2018 of $18.7 billion, in comparison to China, which is at$13.4 billion, in which the GDP of Europe is approximately 40% bigger than China, though the gap is projected to continue to decrease over the ensuing years.
All of this surely indicates that China is on course to soon match and to thereby surpass all of Europe in its GDP, which indicates that China in many important respects will thereby carry far more weight and influence upon world affairs then it did back in 1950, when the populations of Europe and China were about the same. This clearly is indicative that the world is changing and that western civilization and especially Europe must now recognize, if it has not already done so, that the powers to be, cannot be solely western but must be shared with other nations, such as China, Japan, India, Russia, and others.
So too, the productivity of any nation rests upon many factors and facets, of which one of the most salient has to be, the sheer number of peoples contained with a given nation. So that, population matters and if Europe which is slightly bigger in land mass than China in aggregate, had been able to keep their population growth on or around the same trajectory as China achieved over the last seventy odd years, then undoubtedly, the world stage, would be leaning far more to Europe then it does at the present time, of which this path will not easily change in the years to come.
So then, countries that do a poor job in growing their population must surely recognize that nations that do not replace their productive members with additional productive members, no matter their country of origin -- are societies which will inevitably decline. This signifies that those that insist upon closed borders and thereby the exclusion of motivated peoples that wish to immigrate into their countries are in imminent danger of increasing their decline at a more precipitous rate, because the numbers of people contained with a given country, are part and parcel of whether such a nation or confederation of nations, will continue to be relevant or will instead cede their historic place and value to those that are the up and comers.