If we look at the vast advances in food-production technology, known as the green revolution, we would expect to be able to feed everyone on Earth indefinitely. The more people there are, the more inventors and advances in irrigation, agriculture, genetic engineering, pest control, water purification and other methods of increasing the food and water supply beyond what our habitat would provide normally. But in fact, food prices are rising at an alarming rate. The problem, it seems, has to do with the uniquely human byproducts of technological advancement, like systematic habitat destruction. We appear to be using technology in a way that defeats the purpose.
The ideal use of technology -- the use that would extend Earth's carrying capacity -- is to find ways to make fewer resources stretch much farther. Take, for instance, the Earth's energy resources. Ideally, we would've switched en masse to technologies like solar power and electric cars long ago. Instead, we've used technology to simply extract and use more fossil fuels. So instead of technology allowing us to live better on less, we're living better on more.
Since oil is a limited resource, and our technologies like home heating systems and farm equipment still run primarily on oil-dependent power, when we run out of oil, we potentially freeze to death in winter and run out of food. At the same time, air and water pollution resulting from technological advancement is reducing our supply of even more necessary resources.
So, are we doomed? Not if we make lifestyle adjustments that get us back into balance with our habitat. Major worldwide shifts to sustainable energy resources like sun and wind, and a movement toward eating locally grown food, reducing carbon emissions and even taking shorter showers can help. Mining space for additional resources might also help us avoid Earth-wide shortages, although that's a far more uncertain solution to the problem [source: ThinkQuest].
Ultimately, the idea is this: If everyone on Earth can manage to do more with less, we'll be back on track to Earth's indefinite carrying capacity. Also, since economic development and education tends to lower fertility rates, spreading modern knowledge to currently under-developed parts of the world can work as a sort of natural population control, further extending the lifetime of humanity on Earth [source: The Economist].
For more information on carrying capacity and related topics, look over the links on the next page.