Today Is...World Population Day

The cost of food have risen astronomically over the past year, energy prices have shot up and the old guy who changes the numbers at the petrol station is in danger of a heart attack. The atmosphere is dirtier than the latest Jenna Jameson DVD and we are going through the worlds resources quicker than we can replace them.
The great and the good continue to scratch their heads and wonder what can we do about it but the answer is obvious but very uncomfortable. There are just too many of us. Now this is where it gets uncomfortable because just what exactly can we do about it?
We can't order people to stop reproducing and who exactly should not be creating offspring? People who wear Hawaiian shirts i hear you say but that is a given.
The present world's population is around the 8 billion mark and on its current trajectory, is expected to reach 9 billion by the year 2050. According to the CIA's World Factbook, the world human population is increasing by 211,090 every day but how many more of us can our planet sustain?
Based on calculations of the Earth's available resources, the magic figure is 10 billion according to the United Nations Population Division, but that comes with the proviso that our planet can handle 10 billion vegetarians, not that many meat eaters.
The Earth currently has 3.5 billion acres of arable land available which produces approximately 2 billion tons of grains annually and if all that grain was dedicated to feeding humans and none to feed livestock, then 10 billion of us can happily live side by side.  
As it is extremely unlikely that everyone will agree to stop eating meat, the maximum carrying capacity of the Earth based on food resources will fall significantly short of 10 billion, somewhere around the 7 billion figure which is past where we find ourselves now and that is without the complication of arable land becoming infertile due to the consequences of climate change and ensuing desertification and water shortages.
Throw in the issue that an increased population means greater production of the gases that cause global warming and global warming will mean less arable land, then the 10 billion figure is beyond reachable as less and less arable land leads to the current 2 billion tons of grain being reduced and therefore less of us fed.
Our present problems are the symptom but the cause is far too uncomfortable to debate but needs to be addressed somehow. No idea how though without causing outrage somewhere.