This is the Global News podcast from the BBC World Service.

I'm Janet Gillian at 14 hours GMT on Tuesday the 4th of February.

These are our main stories.

China hits back against President Trump's tariffs by saying it will impose its own import taxes on American products.

Police in Sweden say five people have been shot at a school.

The UN calls for the airport in the rebel-held city of Goma

in the east of the Democratic Republic of Congo

to be reopened immediately to address the humanitarian emergency there.

Also in this podcast, as Krill are threatened by global warming.

They also have an incredible capacity to draw down atmospheric carbon

and store it in the deep water, therefore helping us to tackle climate change.

So that's why we call them the superheroes of the southern ocean.

We'll tell you why scientists are monitoring the tiny sea creatures from space.

A new US-China trade war is looming, even as a threat of a North American one has receded for now.

China has announced retaliatory tariffs on the United States in response to Donald Trump's

tariffs of 10% on all Chinese goods which came into effect today. He had planned to impose

hefty tariffs on Canada and Mexico as well, but they were given a last-minute reprieve after pledging to bolster border security.

So that left China on its own, although Mr Trump has also said he's planning to impose tariffs on the European Union as well at some point.

This is how the announcement of China's response was delivered on state television.

On February 1st, the US announced the imposition of a 10% tariff on Chinese products. The actions of

the US seriously damaged the rules-based multilateral trading system and disrupt the stability

of global industrial supply chains.

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