Ethical issues concerning the causes of poverty
Poverty is caused by developing countries themselves
Some people believe that poverty is caused by bad government in developing countries. They argue that it is therefore nothing to do with Western governments, and that we have no responsibility to help people who are poor. This may be linked to ideas like Laissez-faire capitalism. This is the belief that governments should not get involved in wealth distribution, but should leave things to take their natural course.
Some people argue that it is wrong to give large amounts of aid to the developing world, and even argue agaist debt cancellation as an unnatural interference. They say it is better not to get involved, as each economy will find its natural equillibrium. The rich cannot take too much money from the poor, as they need poor people to work the land and produce goods etc. If the balance swings too much in one direction, it will make things change in a way that swings it back
Poverty is caused by the wealthier nations
Many people blame the wealthier nations for the debt problems of the developing world. Money was leant to corrupt governments that misused the money, and it wasn't spent on the people. It is therefore unfair to punish the people for this.
It is also claimed that unfair laws, made by the wealthier nations, have led to an increase in poverty. Trade restrictions make it harder for people in poorer countries to sell their goods. They are also exploited, rarely being given a fair price for their produce.
Other factors
There is probably some truth in both positions above. Wealthy countries can certainly do a lot to stop poverty, but the solution also needs to come from within the developing world. It is also important to note that other factors contribute to poverty. Natural disasters can vastly increase poverty. The spread of diseases, like AIDS, has had a massive impact on Africa.
However, even here it can be claimed that natural disasters have increased because of pollution from developed countries. As a result, the wealthier countris have a responsibility to help reduce poverty.