A very good overview Gary.

But what on earth can we realistically do about it??

What can we do about it?

First of all destroy the humanist impulse by adopting instrumentalism.
Second, instead of out breeding our enemies (blacks, Muslims, Irish, people who go back for seconds), breed them out.
Third, never, ever use logic or rules of evidence in an argument.
Fourth, promote a crisis beyond all bounds of reality.
Fifth, says its not about immigration but population.

There is no evidence or even an argument offered to support the case that 'Had we kept the Earth's population at that (1900)level we would not be having this conversation'. Rich people are forever framing new philosophies for relieving poor people of their property and wealth. The draft Copenhagen Treaty although well disguised as assisting the developing world, was no exception to this rule.
There are valid points and insights raised in the article. However the first step in addressing the population issue is to work from a sound scientific basis. Sadly this article fails to acknowledge that increased CO2 concentrations in the atmosphere help to increase world food production. It also perpetrates the myth of man-made global warming or 'climate change' which I suspect given the current political climate and collapsing climate science, is the main subtle purpose of the article. It is therefore not contributing to the population debate but rather using it for political ideological purposes.
Unless we have international organisations and scientists, independent of government funding concerns, that we can trust on such important matters, we are indeed a long way off addressing the 'real' challenges we face.

Could someone please pass this timely and erudite epistle on to Dr Aaron Paul, Dr Eslake and Bernard Salt.

As has been said often 'economists only look at what interests them in terms of 'economic growth' and totally fail to take in any other parameters'. Economists NEVER give an opinion or forward a view on how to change the cirumstance our economy is placing us in. They only ever explain what happened 'after the fact', too late then!

Economists should never be considered as scientists, 'Academics' may be, because they do not have hypotheses which they 'test' like the rest of us. As shown in this timely piece our economy is driving us to the wall and anyone who does not see it is profoundly deluding themselves. Where are our leaders to show us how to avoid our common demise.

CO2 you are in cloud cuckoo land!
Increased CO2 only works if heat stress doesn't come with it, and even this effect is small.
Your last sentence is a cracker! "Private" science is needed to remove bias!! ROFL! Do you live in a cave? There is practically no such thing as "private science"...almost all real science is public because most private companies want specific pre-determined answers.
To remove bias you go global to harness the competition that exists to be the first, or to knock down the conclusions of the first. This is why international competition between respected opponents is such an essential part of the way science operates. "international organisations" such as BP, Monsanto, etc are a *huge* part of the problem.
Climate science is certainly not collapsing! Over 95% of active climate scientists *still* agree that induced GW is occurring, despite the potentially lucrative opportunities that opposing the conclusions would give them. The fact is that unlike politics, economics, banking, etc, scientist are paid to do repeatable science that is then reviewed by peers and publicly available for ever-after. Despite what you confidently state, almost all the published articles are in support of the CO2 theory. Those that present alternatives generally conclude that they are not superior to the now standard model. There are no valid alternatives that fit the data, except postings on Right wing blogs..but they need not be scientific!

Good article on population.
Ideally the solution would be education, politics, etc.
Alas, "The Solution" will probably be an enclave of culture and technology, armed to the teeth defensively. The enclave should offer to teach and assist, but not save and rescue. I would love the enclave to build a big enough zoo to protect some key ecosystems, but I doubt it will be done in time. Eventually the enclave will deal with environmental issues, but the major challenge will be to deal with hungry deluded "kidult" humans who have lived by insanity of economics and have been led to believe they "deserve" a comfortable life without any ramifications for their actions.
Sad, but nature's way.

Gary Peters quotes from many books but the most telling is when he castigates two writers for not mentioning Paul Ehrlich, the professor who was famously wrong for forecasting that over-population would lead to mass starvation in the 1970s. In fact conditions (mostly) improved.
But Ehrlich was only one of a long line of commentators of varying qualifications who have forecast disaster in coming decades (concerns about over-population date to at least the 1930s) all of which have been disproved, if not completely contradicted, by events.
So why should we believe this set of forecasts of disaster? Peters doesn't bother to tell us.
If he was writing a serious article he could would also have to explain away why there has been a substantial reduction in povery in recent years - so substantial that even the UN agencies have (grudingly) taken notice - and despite increasing population in India and China where the reductions occured.
The reductions have to do with economic reforms in both countries.
Peters may care to have another go at the article.