Would the Planet be Better off Without Humans?

[smartie]

Originally Posted by zan

incidentally, on a slight aside, the growth rate of the human population is slowing. We are due to stop increasing altogether when we hit about 9 billion people, because that's about the point when we will reach the limit of the food\energy\space we can get per capita. This assumes of course that we don't all migrate to the moon or discover how to mine energy from the planet's core or something!

Only a slight aside. Think of the further damage we'll do while we're fighting for the available food/energy/space

[Paul mabbott]

That's because mortality rates are increasing in some parts of the world. There's no sign of birthrate falling which is the only way to sustain life properly. In some parts of the world deaths from disease, starvation and war are increasing while in other parts (e.g. USA) birthrates are going up. Things are better in most of Europe where birth rates are declining to a sustainable level (i.e. two children per adult couple).

Originally Posted by zan

incidentally, on a slight aside, the growth rate of the human population is slowing. We are due to stop increasing altogether when we hit about 9 billion people, because that's about the point when we will reach the limit of the food\energy\space we can get per capita. This assumes of course that we don't all migrate to the moon or discover how to mine energy from the planet's core or something!

[zan]

Originally Posted by Paul mabbott

That's because mortality rates are increasing in some parts of the world. There's no sign of birthrate falling which is the only way to sustain life properly. In some parts of the world deaths from disease, starvation and war are increasing while in other parts (e.g. USA) birthrates are going up. Things are better in most of Europe where birth rates are declining to a sustainable level (i.e. two children per adult couple).

that's not entirely true. You can split the world arbitrarily for this purpose into 'developed' and 'developing'. In the developed world (e.g. europe), generally birth rates have reduced to fall in line with death rates and the populations in these regions are considered stable. In fact, the populations of Scotland and Italy were falling when I studied this in 2006. The demography will change though. There are going to be big problems with life expectancy as the aging population isn't being replaced by as many young people and we are likely to have to face some big problems with supporting the elderly in the future. Overall though, the populations are basically stable.

In the developing world, the death rates are generally falling because of medical advances. In the past, I think human death rates have fallen as a result of improved agriculture and industrialisation. now it's down to medicine. The birth rates are high because generally there is higher childhood mortality, and they are necessary.

However, there is a lag in the cycle which is what causes population growth. death rates must decline before the birth rate, so there will always be a period of faster growth before the birth rates fall into line and slow down.

The USA is an exception, and has a growing population. However, this is because of high immigration rates - the population would probably otherwise be as stable as anywhere else.

Zan

PS - having re-read your post, I think we may actually be agreeing... Sorry if I've misunderstood you!

[Paul mabbott]

Yes. Perhaps the simple answer to the original question is: the planet would be better off without humans reproducing at ever increasing rates. Hopefully if numbers could be reduced voluntarily without depending on war, disease or starvation ....

Originally Posted by zan

that's not entirely true. You can split the world arbitrarily for this purpose into 'developed' and 'developing'. In the developed world (e.g. europe), generally birth rates have reduced to fall in line with death rates and the populations in these regions are considered stable. In fact, the populations of Scotland and Italy were falling when I studied this in 2006. The demography will change though. There are going to be big problems with life expectancy as the aging population isn't being replaced by as many young people and we are likely to have to face some big problems with supporting the elderly in the future. Overall though, the populations are basically stable.

In the developing world, the death rates are generally falling because of medical advances. In the past, I think human death rates have fallen as a result of improved agriculture and industrialisation. now it's down to medicine. The birth rates are high because generally there is higher childhood mortality, and they are necessary.

However, there is a lag in the cycle which is what causes population growth. death rates must decline before the birth rate, so there will always be a period of faster growth before the birth rates fall into line and slow down.

The USA is an exception, and has a growing population. However, this is because of high immigration rates - the population would probably otherwise be as stable as anywhere else.

Zan

PS - having re-read your post, I think we may actually be agreeing... Sorry if I've misunderstood you!