3 of this year's most talked-about topics, explained

From the ongoing COVID-19 pandemic to the metaverse and COP26, 2021 has been another eventful year. As each story has broken, we've sifted through the elements to bring you fact-checked, easy-to-understand explainers. Here's a reminder of some of these pieces, in case you need a refresher.

2021 has seen the rollout of COVID-19 vaccines across the globe. Many nations have vaccinated a large percentage of their populations, but millions are still waiting. We dug into some of the stories behind the headlines.

This year, we've explained how the different vaccine types worked, how vaccine passports might work, and the issue of vaccine nationalism.

And we've also asked what the ingredients are in a COVID-19 vaccine and explored how mRNA vaccines work in more detail.

For many, COVID-19 symptoms have persisted; so-called long COVID. And, for millions of others, the pandemic has impacted their mental health. We asked, What is doomscrolling and how can we stop it?

Given the pandemic's impact, ongoing supply chain and trade challenges, and the changing world of work, the economy has been a hot topic this year.

As part of the Davos Agenda, World Economic Forum Executive Chairman Professor Klaus Schwab explained the difference between stakeholder, shareholder and state capitalism.

We also took a look at the US infrastructure bill with Joel Moser, Professor of International Infrastructure Development and Finance at Columbia University.

And in September, we explained the potential impact of the Evergrande debt crisis on the global economy.

Given the disruption on global trade caused by the COVID-19 pandemic, we used 3 charts to explain how international trade works.

The changes brought about by the COVID-19 pandemic on the world of work also saw us take a look at The Great Resignation with Professor Dr. Isabell Welpe of the Technical University of Munich.

Technology has also shaped the future of the global economy and business, notably around the metaverse. But what is the metaverse? And why should you care?

The state of the environment and the impact of climate change dominated many headlines in the latter part of 2021, as the United Nations COP26 climate conference took place in Glasgow. We asked what is COP26 in this backgrounder to the conference.

It's a complicated path to net-zero though - for example, why are there so many colours of hydrogen? Policymakers and governments also have a significant role to play, so we explored the European Green Deal.

The second half of 2021 also saw global concern over energy supplies and prices. In an interview with Roberto Bocca, we looked at the impact of the energy crisis on the energy transition.

We've explained more about specific weather events, including the North American Heat Dome and La Niña.