Climate change: what is happening, how we know, and what the world agreed.
A blanket of gases, a curve drawn on a Hawaiian volcano, ice that is thinner than it was, and a promise made in Paris by almost every country on Earth. Here is the science of climate change in plain English, with every fact checked against the Met Office, NASA, NOAA, the United Nations and Encyclopaedia Britannica.
The Data Explorer
Slide through the years from 1880 to 2025 and read the real numbers: carbon dioxide measured at Mauna Loa in Hawaii, and the world’s average temperature. Then switch to Higher or Lower and test your eye for the trend.
The Explorer is our own code. It plots NOAA’s yearly Mauna Loa averages and NASA’s yearly GISTEMP figures exactly as published: NOAA Global Monitoring Laboratory: Mauna Loa CO2 annual mean data (text file) NASA GISS: GISTEMP v4 global annual mean data (CSV file)
The short version
Climate change is a large-scale, long-term shift in the planet’s weather patterns and average temperatures. Met Office: What is climate change?
Greenhouse gases act like a blanket round the Earth: sunlight passes through, the ground warms and gives off infrared heat, and some of that heat is caught and sent back down. Met Office: What is climate change?
The Met Office says the evidence is clear: the main cause of climate change is burning fossil fuels such as oil, gas and coal. Met Office: Causes of climate change
The IPCC’s 2021 report says human activity is unequivocally the cause of climate change. Met Office: What is climate change? Some changes can’t now be prevented, but the sooner emissions are cut, the smaller the changes will be. Met Office: Effects of climate change
Explore the topic
What it isClimate change and global warming.
The greenhouse effectA blanket we need, getting thicker.
The causesCoal, oil, gas and forests.
The evidenceThe Keeling Curve and the temperature record.
The effectsSeas, ice, oceans and heat.
The UKWarmer, wetter winters ahead.
How we found outFourier, Tyndall, Arrhenius, Keeling.
Kyoto and ParisWhat the world has agreed.
Myths vs factsThe Sun, volcanoes and other claims.
Tile pictures are credited on their pages and on the credits page.
Things to play
- The Data ExplorerReal CO₂ and temperature numbers, year by year, plus Higher or Lower.
- Cause or Sign?Is it a cause, evidence, an effect or action agreed?
- Climate TimelineFrom Fourier’s “hotbox” in 1824 to the record year of 2024.
- Climate Change QuizTen questions at a time, every answer sourced.
- Picture PairsMatch the scientists, the ice and the instruments.
Found it useful? Help keep this site going.
This site is hand-built, fact-checked and free to use. If the Data Explorer, a game or one of Useless’s notes made you grin, a little support keeps it going and helps the network grow.
Climate change printables
Fact-checked PDFs in A4 and US Letter, sold as instant downloads from the ReallyByte store.
Colour the Greenhouse Effect: Diagram & Colouring Pack
Label-and-colour diagrams of the greenhouse effect, the carbon cycle and rising seas, plus colouring pages of sea ice, glaciers, coral, coasts and a mountain-top observatory
Climate Change Puzzle Pack: Crosswords, Codes & Carbon Logic
A crossword, a word search, a timeline sort, a code-cracker, cause-or-effect sorting and graph-reading puzzles, all with answer keys
Climate Change Fact Cards: Causes, Evidence & Effects
Twenty-four fact-checked cards on the causes, the evidence, the effects, the scientists and the agreements, each with its source
Read the Data: A Climate Graphing Workbook
Plot real NOAA carbon dioxide and NASA temperature figures, read the Keeling Curve, and keep a year of your own weather records
Our Warming World: Kids’ Climate Change Worksheets
For ages 7 to 11: label the greenhouse effect, true or false, cause or effect, climate maths, a maze, colouring, a word search and riddles, with answer keys
Climate Change Poster Set
Six fact-checked posters: what climate change is, the greenhouse effect, the Keeling Curve, warming since 1880, rising seas and the Paris Agreement
Best valueThe Complete Climate Change Printables Bundle
All six packs plus a guide, A4 and US Letter, in one download.