What is global warming?

They are linked but not identical. Global warming refers specifically to the long-term rise in the planet's average surface temperature, measured in degrees Celsius above the pre-industrial level. Climate change describes the much broader set of shifts that result from that warming: changing rainfall and wind patterns, melting glaciers, rising sea levels, ocean acidification, and more frequent and intense extremes such as droughts, heatwaves and floods. In short, global warming is the central cause and climate change is the full set of consequences. Using the more precise term helps separate the symptom — temperature — from the entire system it disrupts. Scientists increasingly favour 'climate change' or 'climate crisis' precisely because the temperature rise is only the beginning of the story.

Yes, and the scientific consensus is overwhelming — more than 97% of climate scientists and every major national academy of sciences agree. The rapid temperature rise since about 1850 is mainly due to human greenhouse-gas emissions, above all the carbon dioxide (CO₂) released by burning coal, oil and gas, plus methane from agriculture and livestock. We know the cause is human from several independent lines of evidence: the extra carbon in the atmosphere carries the isotopic fingerprint of fossil fuels; the upper atmosphere is cooling while the surface warms (the pattern expected from a greenhouse effect, not from a brighter sun); and climate models only reproduce the observed warming when human emissions are included. Natural factors alone — the sun, volcanoes, orbital cycles — cannot explain the trend.

The planet has warmed by roughly 1.1 to 1.3 °C above the pre-industrial average (1850–1900), and the most recent exact figure is shown in the live data block above on this page. That may sound small, but it is a global annual average: a little over 1 °C in the mean hides much larger regional extremes. The Arctic, for example, is warming about three to four times faster than the global average. This much warming is already enough to intensify heatwaves, droughts and heavy downpours, shift growing seasons, and melt ice that took millennia to form. Every additional fraction of a degree measurably worsens these impacts, which is why even tenths of a degree matter when governments negotiate targets.

It is the central goal of the Paris Agreement, signed in 2015 by nearly every country: hold global warming to 1.5 °C above pre-industrial levels, and well below 2 °C. The 1.5 °C figure is not arbitrary — the Intergovernmental Panel on Climate Change (IPCC) showed that impacts rise sharply between 1.5 °C and 2 °C: many more people exposed to extreme heat and water stress, far greater loss of coral reefs, and a higher risk of crossing irreversible tipping points. Temporarily overshooting 1.5 °C is not absolute failure, but every year above that level raises the risks and the chance of lasting damage. Keeping the goal within reach requires cutting global emissions to near net zero by around mid-century — a steep but still achievable path.

Ppm means parts per million, and it measures the concentration of carbon dioxide in the atmosphere — how many molecules of CO₂ there are for every million molecules of air. It is the standard metric for tracking the most important greenhouse gas. Before the Industrial Revolution the concentration was around 280 ppm and had stayed relatively stable for thousands of years. Today it exceeds 420 ppm — the latest value is shown in the data block on this page — a level not seen for at least 3 to 4 million years. This rise comes almost entirely from burning fossil fuels and from deforestation. Because CO₂ lingers in the atmosphere for centuries, the concentration keeps climbing as long as net emissions stay positive, even if the rate of increase slows.

Yes. The science is clear on two points: the warming already underway is largely irreversible on human timescales, but the amount of future warming depends almost entirely on the emissions we make from now on. There is no single threshold beyond which it is simply 'too late' — every tenth of a degree avoided measurably reduces harm. Stabilising the climate requires reaching net-zero CO₂ emissions, meaning we stop adding more carbon than is removed. That is technically possible with technologies that already exist: solar and wind power, electrifying transport and heating, energy efficiency, and protecting forests. The main obstacle is the speed of the transition, not a lack of solutions. Acting early is consistently cheaper than paying for the damage later, which is why the timing of action matters as much as its scale.

Individual choices do matter, especially when they add up and when they shape larger systems. The highest-impact personal actions are usually: cutting home energy use and switching to renewable electricity; favouring public transport, cycling or electric vehicles and flying less; and reducing food waste and heavy meat consumption, particularly beef and lamb. These changes lower emissions and often save money. But the single most powerful individual step is collective: talking about the issue, supporting low-carbon policies, choosing responsible companies and banks, and using your voice as a citizen and consumer. The climate crisis is solved mainly at the level of systems — energy, transport, industry — and it is social demand for change that speeds those systems up. Collective action multiplies the impact of every individual choice.