Which countries emit the most CO2 today? How do annual emissions vary across the world?

Our impact on climate change is not just about emissions that occur today. How much we emitted in the past also matters.

Our World in Data is home to thousands of charts. But some metrics are core to our work: here we present 12 that help us understand the state of the world.

An estimated 8 million tonnes of plastic enter our oceans each year. But the plastic we find in our surface waters is more than 100-fold lower. This is the 'missing plastic' problem.

Maternal mortality was much more common in the past. Today, it is much lower — but there are still large inequalities across the world.

The world needs ideas and innovation to make progress. Creative and talented people are everywhere, but the opportunity to develop is limited to only a small number of well-off children. The world loses out as a result.

Social media sites are used by more than two-thirds of Internet users. How has social media grown over time?

Growing demand for seafood has placed increasing pressures on wild fish populations. One innovation has helped to alleviate some of the pressure on wild fish catch: aquaculture, the practice of fish and seafood farming. Aquaculture production has now overtaken wild fish catch.

The death of a young child has always been the most devastating tragedy mothers and fathers could experience. How common was it?

What does the research tell us about the causal impact of social media use on our well-being?

To understand people’s geographical distribution, we need to look at population density. How does this vary across the world?

In the past the average woman had five children. In the past fifty years, this number has halved as a result of women empowerment, declining child mortality and the rising cost of bringing up children.

Nearly one-in-four adults in the world smokes tobacco. More than one-third of men, but just over 8% of women do. How do sex differences in smoking vary across the world?

One-in-five (20%) of adults in the world smoke tobacco. But where in the world is smoking most common?

Today’s global inequality of opportunity means that the good or bad luck of where you were born matters most for your living conditions. We look at how this chance factor is the strongest determinant of your standard of living, whether in life expectancy, income, or education.

The world has made significant progress in recent decades in reducing deaths from diarrheal diseases, particularly for children. One of the most successful interventions has been oral rehydration therapy (ORT): a simple salt, water and sugar solution. We look at what ORT is, how it was developed, and how many lives it might have saved.

Rotavirus is the leading cause of diarrheal deaths in children. There is, however, an effective tool against it: the rotavirus vaccine.

Despite being treatable and preventable, 1.6 million people died from diarrheal diseases in 2017; one-third were children under five years old. This makes it one of the largest killers of children. Here we look at where and why children are dying from diarrheal diseases, and what we can do to stop this.

Here we look at results from the largest global survey to date – the Wellcome Global Monitor – on attitudes to vaccination across the world.

What effect do public attitudes have on vaccine coverage rates, and what can we do about skepticism to vaccines?

Most of the world’s population growth over the next century is expected to come from Africa.