July 25, 2024
Cases of guinea worm disease have fallen dramatically in recent decades. According to the WHO, over 890,000 cases were recorded worldwide in 1989. As you can see on the chart — which we just updated with the latest data — only 14 human cases were reported in 2023.
Guinea worm disease is caused by the parasitic guinea worm, which mainly spreads through stagnant water sources like ponds. The worm’s larvae enter the human body when a person drinks contaminated water, after which they penetrate the digestive tract to mature and reproduce within the body.
Around a year after the initial infection, the adult female breaks through the skin's surface, creating a painful blister through which it gradually emerges over several weeks. When it comes into contact with water, it releases new larvae and continues its life cycle.
The disease was previously endemic in over 20 countries in South Asia and Africa. An international eradication campaign has substantially decreased the number of cases by improving access to clean drinking water and actively monitoring and containing cases in endemic regions.
Learn more about the effort to eradicate guinea worm disease →
Today
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.
April 25
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.
April 23
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.
April 21
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.
April 18
Cervical cancer death rates among women in the United Kingdom have fallen by around 80% since 1950. You can see this reduction in the chart.
This progress happened for a couple of key reasons.
The first was the introduction of population-level screening programs in 1988. Across the UK, women are invited to get a regular smear test to detect precancerous changes or cervical cancer cases early, when treatment has much better odds of success.
Another, and more recent innovation, which could put the UK on the path to eradicating cervical cancer completely, is the rollout of the human papillomavirus (HPV) vaccine. This protects someone from the HPV infection, which can later develop into cervical cancer.
In schools across the country, girls in their early teens are offered the HPV vaccine, effectively offering them long-lasting protection. I was one of the first cohorts of girls in the UK to receive this, and it’s something I’m incredibly grateful for.
The UK is not alone in its progress: a number of countries have managed to reduce cervical cancer death rates in recent decades.
April 16
France generates two-thirds of its electricity from nuclear power, making it the country’s dominant power source.
As the chart shows, that’s far more than the average across Europe, which is 20%, and the world as a whole, at 9%.
Nuclear power is a low-carbon electricity source, giving France a very clean electricity mix for decades.
Per unit of electricity, France emits far less greenhouse gas than its neighbors and has some of the lowest-carbon power in the world. The global average, based on lifecycle emissions, is 472 grams of carbon dioxide equivalents (CO2e) per kilowatt-hour of electricity generated. In France, this figure is 42 grams.
April 14
In every region of Africa, hunger is more prevalent than a decade ago.
The chart shows the increase in the share of the population that is undernourished, comparing 2014 and 2024 (the most recent year available). These estimates come from the Food and Agriculture Organization of the United Nations.
The situation across Africa is dire. In Middle Africa, where hunger is most acute, almost 1 in 3 people are undernourished. In Eastern Africa, the figure is roughly 1 in 4. Across Africa as a whole, it's 1 in 5.
This marks a reversal of a longer positive trend: over the preceding decades, hunger had been falling across much of the world, including parts of Africa. That progress has now stalled or gone into reverse. Conflict, extreme weather, and the economic disruption of the COVID-19 pandemic have all contributed.
