Low-carbon electricity sources grew faster than demand in 2025, pushing fossil fuels into decline

In 2018, my colleague Max Roser wrote an article titled “The Internet’s history has just begun”. His point was that while the Internet had already changed the world, large changes lay ahead because billions of people weren’t using it yet.

In this chart, I revisit that observation using more recent data from India, the world’s most populous country.

When Max wrote his article, roughly one in five people in India were online. The chart shows that since then, adoption has grown much faster than in the decades before. Today, more than 70% of India’s population is online — close to the global average.

When you look at related trends in the adoption of communication technologies, you see that much of the sudden acceleration in growth after 2018 was driven by mobile phones.

Mobile phone subscriptions in India took off in the early 2000s and had already reached 75 per 100 people by 2015. Internet access accelerated through its mobile networks, which were made affordable by new technologies and market competition — including a major market disruption, which started in 2016 when a new low-cost entrant drove down prices.

Teenage pregnancy rates have fallen across all regions in the last few decades.

The chart shows the number of live births per 1,000 women aged 15 to 19 since 2000, based on data compiled by the United Nations.

Globally, rates have fallen by over one-third. This decline has been even more dramatic in some regions. For example, rates have fallen by over three-quarters in Central and South Asia.

Birth rates have also fallen among adolescents aged 10 to 14 years old, where health concerns for pregnancy in such young girls are even greater.

One way to measure income inequality is to look at the share of all income that goes to the top income earners. The chart plots this for all seven South American countries with comparable 2022 pre-tax income estimates in the World Inequality Database.

The difference between the left and right bars is which earners they cover: the richest 10% on the left, the richest 0.1% on the right.

Looking at the left-hand bars, Colombia ranks top. It has the highest share going to the richest 10%, followed by Chile, Brazil, and Peru — in these four countries, the top 10% share earns more than half of all income. This is high relative to other countries around the world.

But looking at the dark blue bars on the right, the rankings change. Peru’s richest 0.1% receive about 22% of income, the highest in the region by far, and actually the highest in the world that year.

This chart shows just two metrics, but you would also get different pictures if you looked at Gini coefficients or the distribution of wealth instead.

So, what is the most unequal country in South America? It depends on what metric you look at. This is a region with high inequalities, but different indicators will tell you different stories depending on which part of the distribution you examine, and how incomes are measured.

Most people in the world would think very little before flicking on the lights, charging a mobile phone or turning on a laptop to read this.

But that’s a very different reality from the almost 700 million people in the world who have no access to electricity. While this number is large, it has halved this century, falling from 1.35 billion to 675 million. You can see this in the chart.

However, this progress has been far from even. The number has fallen across all regions except Sub-Saharan Africa, where it has increased.

That doesn’t mean no progress has been made: the share of people in Sub-Saharan Africa with electricity has doubled, rising from 26% to 53%. But population growth has outpaced this expansion, meaning the number of people without electricity has still risen.

Fertility rates — which measure the average number of children per woman — have been falling worldwide. Since 1950, global fertility rates have halved, from almost 5 children per woman to 2.2.

As a result, global population growth has slowed dramatically, and many countries' populations are expected to decline by the end of the century.

This is because fertility rates in many countries have fallen below the “replacement level”. This is the level at which a population replaces itself from one generation to the next. It’s generally defined as a rate of 2.1 children per woman.

The map shows which countries had fertility rates above and below this level in 2025. This is based on projections from the UN World Population Prospects.

Most of the world's poorest people still rely on solid fuels — such as crop waste, dung, wood, and charcoal — for cooking and heating.

These fuels generate household air pollution when they’re burned. This has health impacts for those who breathe them in, and can increase the risk of a range of illnesses, including cardiovascular disease, stroke and some cancers.

Estimates from the Institute for Health Metrics and Evaluation suggest that indoor air pollution causes almost three million premature deaths each year. That’s three million people dying earlier than they otherwise would without this pollution.

As shown on the chart, deaths from indoor pollution have fallen as more people get access to cleaner cooking fuels. Improving access to clean energy could prevent many more early deaths.