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Fact check: Why climate change is real

Kathrin Wesolowski
July 15, 2022

Some people still doubt the existence of climate change and question whether humans have really influenced global warming. What does scientific data say? Our fact check gives clear answers.

Forest fire in Portugal
Heat waves, drought and forest fires like this one in Portugal are a danger to the lives of thousands of peopleImage: Joao Henriques/AP Photo/picture alliance/dpa

A severe drought in Monterrey, Mexico; deaths after a fracture of the Marmolada glacier in Italy;  an upcoming heat wave across Europe: This is just a brief list of more and more natural phenomena that climate activists see as obvious evidence that our world is warming fast. 

But there are still people worldwide who deny climate change. According to a YouGov study from 2022 that included 2,059 German participants, 5% do not believe in global warming. In the US, according to a YouGov study from June 2022 with 1,487 respondents, 9% do not believe in climate change and 23% are unsure if it exists.

And the number of climate sceptics has increased: In July 2021, only 6% of the 1,496 respondents did not believe in climate change, while 15% were unsure. 

The almost dry Boca reservoir in northern Mexico
The northern Mexican city of Monterrey has been hit by a monthslong severe drought, as shown by the almost dried-up Boca ReservoirImage: Fernando Llano/AP Photo/picture alliance/dpa

Klaus Oberauer, a cognitive psychologist at the University of Zurich, told DW that it does not depend on the level of education whether someone believes in climate change or not. He calls climate change denial a "sophisticated political strategy": People define a scientific question in terms of a particular worldview in order to identify with a certain political orientation.

However, the question of whether climate change exists is not a question of feelings or of a certain view of the world, but one of facts. This fact check intends to provide these.

Claim: "There is no global warming, no climate change,"a user writes on Twitter (archived here) — and publishes a CNN interview with the meteorologist John Coleman, the co-founder of the Weather Channel. In the interview, he denies global warming exists.

DW fact check: False

The video was screened on TV back in 2014. The Weather Channel clearly distanced itself from Coleman's statements. According to media reports, the meteorologist died in 2018 — yet climate deniers keep referring to him as a living and relevant presence. The statement in the tweet is unproven and contradicts scientific findings.

Is climate change scientifically proven?

Yes, global warming and climate change are scientifically proven — and have been for decades. In fact, researchers have found that climate change began over 180 years ago, at the start of the Industrial Revolution. In the Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), scientists from 195 countries write that there is growing evidence of weather extremes such as heat waves, heavy precipitation, droughts and tropical cyclones. Additionally, they found proof of human influence in global warming.

One year after the flood

For their world climate reports, the experts analyze tens of thousands of studies. The panel already stated in 1995: "The balance of evidence suggests a discernible human influence on global climate."

In an overview, the German Climate Consortium (DKK) states that all parts of the climate system, such as oceans, ice, land, atmosphere and biosphere, have warmed up significantly in recent decades and that the air on the Earth's surface is, on global average, already more than 1 degree Celsius (1.8 degrees Fahrenheit) warmer than in the pre-industrial period. 

According to experts, the goal must be to keep global warming below 1.5 degrees Celsius by 2100. Otherwise, the climate impacts will become more and more damaging to humans and the entire planet, sea levels will continue to rise and weather conditions will become more extreme. 

"One point five degrees of global warming," Claas Teichmann, a scientist at the Climate Service Center Germany, told DW. "That means 1.5 degrees of warming on a global average, because it tends to warm up more over the continents than over the ocean, which has a certain cooling effect due to evaporation." This means that in many regions, it will not be 1.5 degrees Celsius warmer but even hotter than that.  

Infografik - Temperatur Anomalien, 1880 - 2022 - EN

Is climate change caused by humans?

Hundreds of research institutions worldwide agree that the current rapid rate of climate change is caused by human activity. A US study analyzed 88,125 climate studies and concluded that 99% of the studies agree that humans play an overwhelming role in climate change. With the help of models, it is possible to simulate how the climate would have developed without anthropogenic influences and how it finally developed with those influences.

In 2021, NASA published a study in which researchers used satellite observations of the Earth's radiation to prove that current rapid climate change is not natural but a product of human activity. 

When fossil fuels such as coal, oil or natural gas are burned, the greenhouse gas carbon dioxide is produced. Together with other greenhouse gases, this blocks heat radiation, causing the Earth to warm up. "In 2020, the annual average CO2 concentrations were almost 50% higher than before the start of industrialization," the website of the German Climate Consortium (DKK) states.

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On July 12, 2022, the average global level of atmospheric CO2 was 417 ppm. The last time CO2 levels were so elevated was some 3 million years ago, when sea levels were around 30 meters (100 feet) higher and modern humans didn't even exist. According to researchers, at that time, it was much warmer overall and there was less ice on the planet. DW published a detailed fact check on human-driven climate change in 2021.

Which recent natural disasters can be attributed to climate change?

"For statistical reasons, you cannot conclude from an individual event that there is a global or long-term change in the climate," Andreas Becker, head of the Climate Monitoring Department of the German Weather Service, told DW. "But we can calculate with probabilities."

Marie-Luise Beck, managing director of the German Climate Consortium, confirmed this via mail. "Due to climate change, extremes change in terms of frequency and intensity, which means weather extremes become more frequent and they are stronger," Beck explains.

According to an international study, the probability of the kind of extreme rainfall that led to flooding in Germany, Belgium, the Netherlands and Luxembourg in 2021 has increased by a factor of 1.2 to nine. 

Even so, we are talking about massive periods of time, Becker explains, as the event is still very rare even with climate change. "We're talking about several hundred years here. Without climate change such rainfall would only have occurred every 20,000 years," the meteorologist says.  

A destroyed bridge and car in a river
The flood disaster in Germany's Ahr valley last year killed 134 peopleImage: Joerg Niebergall/Eibner-Pressefoto/picture alliance

"It is also clear from the study that the intensity of these extreme rainfall events has increased between 3 and 19% due to human-induced global warming in the region," a statement on the study says.

The chief meteorologist and climate specialist of the US channel WFLA News, Jeffrey Berardelli, gave DW another example: "More recently the spring India and Pakistan heat wave which caused the Glacial Lake Outburst flood was made 30 times more likely by climate change." 


There is almost 100% scientific consensus that the climate is changing — and that humans are responsible. This is associated with an increase in weather extremes that are life-threatening for humans and the entire planet.

Collaboration: Tetyana Klug

Edited by: Timothy Jones

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