April 07, 2025
Polio is an infectious disease that primarily impacts children, and can cause paralysis and even death. In the first half of the twentieth century, thousands to tens of thousands of people suffered from paralysis from this terrible disease every year.
The first injectable vaccine against polio was introduced in the United States in 1955. Six years later, a second vaccine was introduced, which could be taken orally.
By 1961, over 85% of US children under ten had received at least one vaccination against polio.
As a result, the last wild polio outbreak in the US occurred in 1979, and the disease was officially eliminated from North, Central, and South America in 1994. This means it was not spreading within this region, and any new cases were only seen among individuals infected elsewhere.
Read our colleague Max’s article about the global fight against polio →
April 21
Fifty years ago, almost half the adults in Great Britain smoked cigarettes, but this has become much less common.
In the 1970s, half of men and 40% of women over the age of 16 reported smoking cigarettes. Since then, smoking rates have steadily fallen. By 2023, this was just 12% of men and 10% of women.
This dramatic decline is the result of decades of public health efforts such as clear warnings on cigarette packs, bans on tobacco advertising, indoor smoking restrictions, and support to help people quit. Newer technologies — including vaping products, nicotine patches, and medications — have also helped many people quit.
Despite this, smoking remains the leading risk factor for preventable death in the UK, raising the risk of many cancers, heart attacks, and strokes. Fewer smokers means fewer people suffering from these serious diseases.
Read more about the global problem of smoking in an article by my colleague Max →
April 18
A recent report by the Inter-American Development Bank (IDB) highlights the high concentration of poverty in Latin America. Across the region, around 89 million people — more than one in seven — live on less than $3.65 a day.
Poverty can be measured using various poverty lines; here, we’re looking at the $3.65 line, which the World Bank uses to define poverty in lower-middle-income countries.
The chart shows that 52.2 million people living under this line are in just three countries — Brazil, Venezuela, and Mexico — representing 59% of the region’s total.
As the report explains, while Brazil and Mexico don’t have the highest poverty rates, their large populations mean they have the largest number of people living below this line. Venezuela, in contrast, has a smaller population but one of the region’s highest poverty rates.
Identifying where poverty is most concentrated can help target efforts to reduce and eliminate it.
You can explore more data on poverty, including different poverty lines and world regions, in our Poverty Data Explorer →
April 16
One of the most pressing problems I hear from European friends is that they cannot find an affordable place to live. Housing costs represent one of the largest expenses for most Europeans. While many people rent, purchasing a home remains a goal for some.
The chart shows the change in house prices of residential properties purchased by households in 12 countries across the European Union since 2010. In many, prices have increased sharply (even after inflation). Portugal shows the most dramatic increase, with prices rising by 50%.
But this large increase has not happened everywhere. Rises have been more modest in France and Belgium, and prices have actually fallen considerably in Romania and Italy.
These huge differences matter to young Europeans hoping to find their first home after leaving their family house.
April 14
It’s often difficult to understand the scale of wildfires globally. That’s because most news coverage focuses on only a few countries.
News headlines might be filled with stories about large fires in Greece, Portugal, the United States, or Canada, but when we look at the data, the global total is no higher than usual.
This is because the global trend is so strongly dictated by the extent of fires in Africa, which we almost never hear about. As you can see in the chart, Africa experiences more than half of the burned area globally every year. In some years, it’s as much as two-thirds of the total.
Whether it’s a “high” or “low” year for wildfires globally largely reflects whether it’s a high or low year for Africa. These global trends don’t tell us much about the extent of wildfires in other regions.
Track global, regional, and country-level data on wildfires, which we update weekly →
April 11
Global air travel collapsed in 2020 as lockdowns and travel restrictions took effect. With fewer flights, CO₂ emissions from commercial aviation fell sharply. The chart shows Egypt as an example, where they dropped by more than half.
As air travel rebounded, emissions rose too — in many countries, they’ve now surpassed pre-pandemic levels. These countries are highlighted in red on the chart.
Emissions from flying make up about 2.5% of global CO₂ emissions, but air travel has one of the highest carbon footprints per passenger. As demand grows, reducing its impact will be important for meeting climate goals.
Read my colleague Hannah Ritchie’s article to learn more about aviation’s contribution to global CO₂ emissions →
April 10
The peak flowering of cherry trees in Kyoto, Japan, has been recorded since the ninth century. Yasuyuki Aono and colleagues from the Osaka Prefecture University collated this data from historical diaries and chronicles, indicating the dates on which cherry blossom viewing parties had been held or other observations of peak blossom.
In 2025, the peak cherry blossom happened on April 4th.
This long-run data is a proxy measure for how the climate has changed. The onset of cherry blossoms is linked with warmer temperatures. Since the early 20th century, the combined effects of urbanization and higher temperatures due to climate change have gradually moved the peak blossom earlier in the year.
Explore this data in our interactive visualization →
April 09
The world is heating up. By the 2010s, the global average temperature of the air above the surface was about 1°C higher than in the 1940s. But some regions are warming much faster.
The chart shows how average surface air temperatures have changed each decade across continents and oceans compared to historical averages.
The Arctic warmed more than any other region — by the 2010s, it was 2.8°C hotter than in the 1940s.
In the Arctic, melting sea ice has amplified this temperature increase: ice reflects sunlight, so having less of it leads to more warming.
Europe was in second. Since land heats up faster than water, its mostly land-based geography has increased its rate of warming. It has also seen a rapid reduction in aerosols from air pollution. These improvements in air quality can inadvertently increase temperatures because there are fewer aerosols to reflect sunlight.
You can explore how temperatures in each continent, ocean, and country have changed over time →
