Is climate change real, and is it natural?
Written by AI from saved sources. A script checks every quote word for word, and a second AI compares each claim with its source. How we work and corrections
Yes, the world is warming. Human influence is the main cause of the recent long-term rise. Earth's climate changed naturally before, and natural swings still affect temperatures.
Checked: NASA, IPCC, National Academy of Sciences/Royal Society, October 2026.
Why people believe it
Earlier warming and cooling are a reasonable starting point: natural climate change is real. Participants in Pew's 2023 interviews often cited earlier warming and cooling as evidence of natural cycles at that time. Its 32 US adults were selected for saying climate action was not a top national priority. They were also selected for saying humans were not the primary cause of warming. They were not representative of all US adults.
A research review compared what predicted belief in climate change. Values, belief systems, worldviews and political views predicted belief more strongly than factors like education and experience of extreme weather. It combined 25 polls and 171 academic studies across 56 nations.
“Is the warming actually measured?”
NASA uses weather stations, ships, buoys (floating instruments) and Antarctic observations. Its methods account for urban heating and changes in the distribution of temperature stations. It reports 2025 was 1.19°C above its 1951–1980 average. NOAA reports 1.34°C above 1850–1900. Those comparisons use different starting periods. Teams share much of the data they use, but different methods find the same warming trend.
“The climate has always changed”
It has: repeated changes in Earth's orbit (its path around the Sun) trigger ice ages. Over thousands of years, changes in ice cover and what the atmosphere contains amplify the small changes in solar energy caused by these orbital variations. IPCC says the worldwide extent and speed of recent warming are unusual.
“Could it be the Sun?”
IPCC reports no significant change in total solar irradiance (incoming solar energy) between 1986 and 2019. Changes in Earth's orbit happen over thousands of years. They had very little influence on temperature changes over the past century.
“What about volcanoes and ocean cycles?”
Large volcanic eruptions can cool the surface by adding particles that reflect sunlight. This cooling typically fades within a decade. Natural swings within the climate move energy around. They can strengthen, weaken or temporarily reverse surface warming over a couple of decades or less.
“How do we know humans are involved?”
Researchers compare observations with computer simulations of different causes. Simulations using only natural processes cannot reproduce the observed global warming over 1850–2019. These processes are solar changes, volcanoes and internal swings.
Thinking tool: compare the fingerprints
Ask what each proposed cause predicts, then compare those predictions with observations. More energy from the Sun would warm the troposphere (the lower atmosphere). It would also warm the full stratosphere (the layer above it). Human-caused increases in carbon dioxide were predicted to warm the troposphere and cool the stratosphere. Weather-balloon and satellite measurements show that combination.
One pattern needs context. The lower stratosphere cooled from 1979 to the mid-1990s. IPCC says this was mainly due to human-caused loss of ozone, a gas in the atmosphere. It calls this extremely likely. Ocean warming and melting sea ice provide other evidence.
For other claims, ask which observations would distinguish the proposed explanation from its alternatives.
Official positions, with dates
IPCC's 2021 assessment calls human warming of the atmosphere, ocean and land unequivocal (leaving no doubt). Its 2023 summary says human activities, chiefly greenhouse-gas emissions, unequivocally caused global warming.
What remains uncertain?
The size of human influence on Atlantic and Pacific variations over decades remains uncertain. Models still differ from observations in regional patterns of precipitation (rain, snow and other falling water).
What people also ask
Has global warming slowed down?
During 1998–2012, natural swings and solar and volcanic changes partly offset human-caused surface warming. IPCC assesses this with high confidence. Ocean heat continued increasing throughout, with very high confidence.
Is climate change 100% man-made?
Natural changes still occur, but they alone do not explain the sustained recent warming. IPCC's best estimate for human-caused warming from 1850–1900 to 2010–2019 is 1.07°C. The likely range is 0.8–1.3°C. Here, “likely” means 66–100% probability.
What do 97% of scientists believe is causing climate change?
A 2013 study found 97.1% support for human-caused warming among paper summaries (abstracts) expressing a position. Of the sampled abstracts, 66.4% expressed no position. A 2014 critique called the results biased and the sample not representative. The study's authors replied that the critique contained a calculation error.
What are some examples of evidence of climate change?
Evidence includes measured surface warming, ocean warming and melting sea ice. The contrasting temperature changes in layers of the atmosphere also contribute evidence.
Check it yourself (5 minutes)
- Open IPCC's Chapter 2: Changing State of the Climate System (2021).
- Find “FAQ 2.1”, then “always changed naturally”.
- Read the sentence: does acknowledging natural change mean recent warming is ordinary?
What you should have found
“Earth’s climate has always changed naturally, but both the global extent and rate of recent warming are unusual.”
Before you forward this: does the box at the top say exactly what the sources below say?