How have humans reshaped the world’s land over the last 12,000 years?

Researchers and policymakers often need to compare countries by income, which means having clear criteria for who counts as "rich" or "poor".

One widely used approach is the World Bank’s (WB) income classification system, which places countries into four groups — low, lower-middle, upper-middle, and high income — based on their gross national income per capita in the previous year.

These income groups are used across many international datasets, such as the WB’s World Development Indicators — which include information on topics from access to energy and education to global trade — and are often cited in research and the media.

I recently updated our charts with the latest WB classification, published in July this year based on incomes in 2025. You can see this in the map. The WB publishes updates every July, so we'll refresh our charts again in 2027.

Global whale populations fell dramatically over the 20th century due to human hunting. Some whale species were pushed to the brink of extinction.

But a combination of conservation efforts, technological change, economic incentives, and international policies has reduced global whaling to much lower levels. In the mid-1980s, a global moratorium was agreed by the International Whaling Commission (IWC), making commercial whaling illegal.

You can see this decline in the chart, which shows the number of whales killed per decade. The chart combines data from two sources: before the 1990s it comes from the paper “Emptying the Oceans” by Robert C. Rocha, Jr. and colleagues; since then, it comes from the IWC.

While whaling activity is much lower, it hasn’t been eliminated completely. There are exceptions to the IWC’s moratorium, and Japan withdrew from the IWC completely in 2019.

I recently updated our charts with the IWC’s latest annual release, which includes the numbers of whales caught and killed up to 2024.

Guinea worm disease, also known as “dracunculiasis”, is a painful and debilitating parasitic infection. The guinea worm’s larvae can invade a person’s stomach and intestines when they drink contaminated water, such as from a stagnant pond.

The larvae mature into adult worms, often a meter long, which crawl through tissues and joints. This can cause severe arthritic conditions or permanent disability. About a year later, the worm emerges through a painful skin blister, risking secondary infections.

The disease was previously endemic in over 20 countries in South Asia and Africa. According to the World Health Organization (WHO), nearly 900,000 cases were recorded worldwide in 1989. You can see this in the chart.

Unfortunately, there are no vaccines against guinea worm disease. But prevention is possible through clean water access, insecticides, and active case monitoring.

An international eradication campaign using these preventative measures has drastically reduced the number of guinea worm disease cases globally. By 2025, only 10 were reported, the lowest number on record.

Full eradication is within reach, and tracking progress is key to achieving that. The WHO tracks this and publishes the “Dracunculiasis eradication: global surveillance summary” once a year. I recently updated our charts with the latest data from the WHO.

To understand how health is changing on a global scale, we need data that covers a multitude of health indicators across all countries and over many decades.

One of the primary datasets we have for this is the Global Health Observatory (GHO) from the WHO. It’s the WHO’s main repository of health statistics, covering more than 1,000 indicators for its 194 member states over the last decades.

The data covers a very wide range of areas, from life expectancy and child mortality to immunization, mental health, road safety, alcohol and tobacco use, and obesity.

In the map here you can see one example from the GHO’s vast database: the share of adults who are obese in countries across the world. In 2024 the global average was 16%, but ranged from under 3% in some countries to over 70% in others.

The GHO is the source behind many of our most-viewed charts on global health. I recently updated our charts with the latest release.

Among all the charts on our site, the one below reaches further back in time than almost any other: the concentration of CO₂ in Earth’s atmosphere over the last 800,000 years.

For most of that time, CO₂ rose and fell between roughly 180 and 300 parts per million (ppm), driven by natural cycles in Earth’s orbit. We know this from cores of Antarctic ice, which trapped tiny bubbles of ancient air as it formed.

By 2025, the concentration — now measured by NOAA’s Global Monitoring Laboratory — reached 426 ppm, higher than at any point in that record. Concentrations over the past decade have been rising at 2 to 3 ppm each year.

This dramatic increase in CO₂ is mainly from human activity; this and other greenhouse gas emissions are the primary drivers of current climate change.

CO₂ concentration is just one of the indicators we use to track a changing climate. Others include global temperatures, ocean heat content, and snow cover. Each of these is compiled by a dedicated scientific institution, from the UK’s Met Office Hadley Centre to NOAA in the US.

I recently updated our climate charts with the latest data from these sources, something I do every month.