With the world's population at 7 billion, will there be enough resources for us all? Or is Malthus correct and our supplies will start to run out?
Malthus was wrong 200 years ago and I do not think that his theories apply today either. They certainly do not apply to food resources, though eventually they will have to apply to energy sources if we do not find efficient ways to reduce our energy use and more renewable energy sources.
We have no real shortage of food in the world today. There is, to be sure, hunger in some places. However, the problem is that the food is not well distributed around the world. We have enough food for everyone, but the food is concentrated in some countries and so there are still people who go hungry. If we do have issues with starvation, it will not be beacuse of lack of resources.
What may be a problem is our sources of energy. This is not what Malthus was talking about, but we will surely at some point start running out of things like oil and natural gas. However, this point is not particularly near at hand.
I think it is also important to point out that, especially with Climate Change and the long term effects of it, we may well run short of fresh water without new technology to more cheaply and widely desalinate seawater.
Up until now our main sources of drinking water have come from mountain and glacial runoff. Climate change is destroying those glacial systems. The Himalayas, for example, supply most of the drinking water for 40% of the world's people. We'll need to replace these sources of water if we are going to be able to sustain a large world population.