What Is Anthropogenic Global Warming?
Anthropogenic global warming means human actions are the main cause of Earths recent warming. This guide explains how we know and why it matters.
Short answer
Anthropogenic global warming means the Earth is getting warmer mainly because people burn fossil fuels and change the land. Scientists call it "anthropogenic" because the cause is human activity, not natural cycles alone. See the NASA overview of causes and the United Nations explanation for more detail.
What the phrase means
Break the words down: "anthropogenic" = made by people. "Global warming" = the average temperature of Earth is rising. Put together, the term points to the steady rise in global temperature that is driven mostly by human actions since the Industrial Revolution.
How it works
The planet stays warm because of the greenhouse effect. Sunlight reaches Earth and warms the land and oceans. The Earth sends some of that heat back into space. Certain gases trap some of that outgoing heat, keeping the planet warmer. Humans add extra greenhouse gases, like carbon dioxide and methane, which act like a thicker blanket and trap more heat.
Simple steps in the process
- People burn coal, oil, and gas for energy.
- This releases extra carbon dioxide (CO2) into the air.
- Higher CO2 levels trap more heat around Earth.
- Global average temperatures rise, changing weather and oceans.
Key evidence that people are the main cause
Scientists rely on many kinds of proof. Together they form a strong picture that humans are responsible for most of the warming we see now.
Main lines of evidence
- Rising greenhouse gases: We measure CO2 in the air and see it is much higher than before industry. NASA and other agencies show this long-term rise in their evidence pages.
- Fingerprint of fossil fuels: Carbon from fossil fuels has a chemical signature scientists can detect. This shows the added CO2 comes from burning fossil fuels.
- Energy imbalance: Satellites and ocean heat measurements show Earth keeps more energy than it loses. That extra energy matches what extra greenhouse gases would cause.
- Climate models: Computer models reproduce recent warming only when they include human greenhouse gas emissions. Natural factors alone do not explain the trend.
- Patterns match expectations: For example, the upper atmosphere cools while the surface warms — this is what greenhouse warming predicts, not what more sunlight would cause.
For a readable guide to these proofs, see the Royal Society summary and the EPA causes page.
Natural vs. human causes — a quick comparison
| Driver | How it changes climate | Role today |
|---|---|---|
| Sun | Brightens or dims, changes heat input | Small changes; does not explain recent warming |
| Volcanoes | Can cool for a few years by adding particles | Short-term dips, not the long rise in temperature |
| Greenhouse gases (CO2, CH4) | Trap heat in atmosphere | Human emissions are the main reason levels are now much higher |
The long-term rise in temperature matches the steady increase in human emissions since the 1800s, especially after 1950. Scientists have studied natural causes and find they are too small or the wrong pattern to explain today’s warming. See NRDC on causes for an accessible explanation.
One clear data point
Global temperatures have risen about 1.1 degrees Celsius (about 2 degrees Fahrenheit) since 1850-1900, and scientists link nearly all that rise to human activities. This is a small number that matters a lot because it changes weather, sea ice, and oceans. The NASA evidence page summarizes this data.
Why it matters (practical implication)
Warmer average temperatures change rainfall, raise sea level, and increase heat waves. That affects food, health, and where people can live. Knowing humans are the main cause means we can choose to reduce emissions and slow further warming. Actions like switching to clean energy, protecting forests, and using less fossil fuel make a difference.
What scientists agree on
There is a strong scientific consensus that humans are the main driver of recent warming. Major science bodies around the world, including the Intergovernmental Panel on Climate Change (IPCC) summaries cited by NASA and the United Nations, state that human influence is clear and growing.
Myth-busting FAQ
Is modern warming just a natural cycle?
No. Natural cycles happen, but the speed and pattern of recent warming match human greenhouse gas rises, not natural changes.
Is the sun to blame?
No. The sun’s output has not increased enough to explain recent warming. Models that add sun changes still need human emissions to match observations.
Won't CO2 return to normal by itself?
CO2 stays in the atmosphere for decades to centuries. If we keep emitting, levels and warming will keep rising.
How people can act
- Reduce energy use and waste at home and work.
- Support clean energy like wind and solar.
- Protect and restore forests that absorb carbon.
- Learn and vote for policies that cut emissions.
For trustworthy guides on what to do and why, see NASA, the EPA, and the UN.
Further reading
- NASA on effects of climate change
- NASA on causes of climate change
- Royal Society evidence and causes
- ScienceAlert explainer
Plain, tested science shows humans are driving current global warming. Understanding that gives us the power to change course.
Dr. Verde leads climate research initiatives and translates complex environmental science into actionable insights. Published researcher with expertise in carbon cycle modeling and renewable energy systems.
