I don't think that overpopulation will a problem in the long term :
First, most (if it's not all) of the Western countries will soon have their population declining.
Second, China (1.3 Billion inhabitants) has the same fertility as France, ie its population growth is under control and does not represent any problem.
So only India (pop. : 1 Billion, fertility: 2.98 in 2003) stands. Its true that with a density equal to 345 inhabitants per square kilometer, it is a problem; But according to the UN statistics and estimates, its fertility will progressively fall under 2.00 around year 2020. Plus India will be able to provide workers for Western countries, which will have an larger proportion of pensioners.
This is my first thought...
Now let's see some figures !!!! *crazy*
Yerss => Hehe
Things we knew : In Europe the pop will drop.
In China it will start decreasing after 2030
________________________________________
China
Population (thousands)
Medium variant
2000-2050
Year Population
2000 : 1 275 215
2005 : 1 322 273
2010 : 1 364 875
2015 : 1 402 321
2020 : 1 429 473
2025 : 1 445 100
2030 : 1 450 521
2035 : 1 448 112
2040 : 1 438 933
2045 : 1 421 133
2050 : 1 395 182
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Europe
Population (thousands)
Medium variant
2000-2050
Year Population
2000 : 727 986
2005 : 724 722
2010 : 719 714
2015 : 713 402
2020 : 705 410
2025 : 696 036
2030 : 685 440
2035 : 673 638
2040 : 660 645
2045 : 646 630
2050 : 631 938