The bottom half of humanity is living in severe poverty; not all of them are malnourished or severely deprived now, but they are extremely vulnerable to even small upsets in their income or in the prices they face of basic necessities, and when something like this happens, they can be thrown off kilter in terms of a disease of a family member or a change in food prices; anything like that can throw them into destitution.

What we should do is require or at least permit innovators to license their green innovations free of charge in exchange for public payments based on the impact this innovation has on the environment - emissions averted or something of this sort.

In the domain of pharmaceuticals, we need a metric for health impact, and with this metric we can then assess the value of the introduction of a new product and pay its innovator accordingly, say on the basis of the product's measured health impact during its first ten years on the market. In exchange, innovators must of course renounce the usual rewards they are otherwise entitled to, namely the patent-protected markup on the price of their product.

The massive corruption common in so many developing countries would be quite impossible if Western countries did not provide convenient opportunities to ship ill-gotten funds out of the country. It wouldn't make much sense for a ruler to store in his basement large quantities of stolen cash in his own country's currency. A corrupt ruler wants to be able to keep this money safe and to be able to spend it. And for this, he needs to convert it into a Western currency and store it in a bank abroad, where it can also earn investment returns and be bequeathed to his heirs.

By using general consumption PPPs, the World Bank is, in effect, saying to the poor: "Sure, you cannot buy as much food as the dollar value we attribute to your income would buy in the United States. But then you can buy much more by way of services than you could buy with this PPP equivalent in the United States." But what consolation is this? The poor do not buy services - they are services, on their luckier days.

I think one big improvement would be if we somehow made it cheaper and easier for developing countries to learn from the sad experience of some of the developed countries, and also from some of the positive experiences we have of building good transportation systems, like high-speed rail.

It is irrational to charge high prices for socially valuable innovations as this guarantees that they will be underutilized. It is much better to sell them at cost and then to reward the innovator in some other way. This is not always possible, because in some cases the value of an innovation is in the eye of the beholder; it's very difficult to value how much a new Madonna song is worth, for example. But in the case of medicines, green technologies and seeds in agriculture, such an alternative reward mechanism is fairly straightforward.