Hello and welcome to the Intelligence on Economist Radio.

I'm your host, Jason Palmer.

Every weekday we provide a fresh perspective on the events shaping your world.

Usually, scientists can't pin a given weather event on climate change.

They can only say it was made more likely.

But some cases are so extreme that they permit no other explanation,

like the current heat wave and rash of fires in Siberia.

And some passports give a lot more freedom to move than others do,

a fact that many Africans know all too well.

So those who can afford it are looking beyond their own country's limited documents

and shopping around for something a bit more permissive.

But first, on Friday, Vietnam banned imports of wildlife

and the markets where animals are sold,

and in evident bid to limit future outbreaks of disease.

Attention has focused on the wildlife trade ever since the first known outbreak of COVID-19

was traced to a so-called wet market in China.

The virus is believed to have emerged in the Chinese city Wuhan late last year.

It has spread to humans via a seafood market in Wuhan,

where the virus was first identified.

The virus is speculated to have spread from bats to penguins to humans.

At times, the origin of the virus was much more a political question than a scientific one.

The Trump administration clearly wants to blame China for exporting it,

...