Looking for logical flaws in resource based economy

If there is a huge natural disaster such as a flood or drought, where is help going to come from?
The resource (food, shelter, fuel etc) is not available in that local area. In fact the global economy is short by some hectares-worth of wheat or equivalent. It may be deemed that the area is at risk and not suitable for population as is may be unable to sustain a society - all resource needing to be shipped in and nothing to export. This would cause higher density of population elsewhere, assuming people were prepared to move 'for the greater good'.
If I produce cabbages and wish to have a car from the local car manufacturer, he may have more trouble than me getting rid of a year's worth of cabbages, better to convert both to a monetry value so we can trade.
How to encourage the less-willing to work harder? Do you starve them? They haven't contributed as much as others, but what are you going to withhold to get them to help?
On a smallholding principle, producing diverse crops and all that is necessary this may be possible, but less efficient in many ways from having large farm specialising in producing one particular crop. This causes overproduction in some areas, all excesses need to be transported and exchanged with others. Some areas will remain self-sufficient, whereas others will have overproduction in one crop which they may be unable to exchange with the self-sufficient area for some necessary resource that they are unable to produce themselves (due to climate, soil etc). With the present system they are able to encourage an exchange by selling the overproduced crop at a much lower price than that produced in the self-sufficien areas and so population is able to spread over a greater area of the globe.