Is climate change real?

Is climate change real? I'll pull the latest scientific evidence to answer.

Yes, climate change is real - this is the established position of the overwhelming majority of climate scientists and every major scientific organization in the world.

1. Scientific consensus is overwhelming

Scientific evidence continues to show that human activities (primarily the human burning of fossil fuels) have warmed Earth's surface and its ocean basins, which in turn have continued to impact Earth's climate.

NASA's climate portal presents the state of scientific knowledge about climate change while highlighting the role NASA plays in better understanding our home planet, and notes that multiple studies published in peer-reviewed scientific journals show that climate-warming trends over the past century are extremely likely due to human activities.

Major scientific bodies state it explicitly:

•Statement from 18 Scientific Associations (2009): "Observations throughout the world make it clear that climate change is occurring, and rigorous scientific research demonstrates that the greenhouse gases emitted by human activities are the primary driver."

•American Association for the Advancement of Science: "Based on well-established evidence, about 97% of climate scientists have concluded that human-caused climate change is happening."

•American Geophysical Union: "Based on extensive scientific evidence, it is extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century."

•Joint statement of 11 international science academies: "Climate change is real. There will always be uncertainty in understanding a system as complex as the world's climate. However there is now strong evidence that significant global warming is occurring."

•U.S. National Academy of Sciences: "Scientists have known for some time, from multiple lines of evidence, that humans are changing Earth's climate, primarily through greenhouse gas emissions."

The U.S. government assessment echoed this: "Earth's climate is now changing faster than at any point in the history of modern civilization, primarily as a result of human activities."

2. The Intergovernmental Panel on Climate Change (IPCC) position

The Intergovernmental Panel on Climate Change (IPCC) has unequivocally confirmed in its reports that climate change is real and that human-made greenhouse gas emissions are its primary cause.

In its most recent assessments the IPCC stated:

> "It is unequivocal that the increase of CO2, methane, and nitrous oxide in the atmosphere over the industrial era is the result of human activities and that human influence is the principal driver of many changes observed across the atmosphere, ocean, cryosphere, and biosphere."

> "Since systematic scientific assessments began in the 1970s, the influence of human activity on the warming of the climate system has evolved from theory to established fact."

Its Sixth Assessment Report concluded that human influence has unequivocally warmed the atmosphere, ocean and land.

3. The evidence

NASA and other agencies point out that while Earth's climate has changed throughout its history, the current warming is different:

> "The current warming trend is different because it is clearly the result of human activities since the mid-1800s, and is proceeding at a rate not seen over many recent millennia."

Specific observed changes include:

•Global temperature: The planet's average surface temperature has risen about 2 degrees Fahrenheit (1 degrees Celsius) since the late 19th century, a change driven largely by increased carbon dioxide emissions into the atmosphere and other human activities.

•Ocean warming: The ocean has absorbed much of this increased heat, with the top 100 meters of ocean showing warming of 0.67 degrees Fahrenheit since 1969.

•Ice sheets shrinking: Data from NASA's Gravity Recovery and Climate Experiment show Greenland lost an average of 279 billion tons of ice per year between 1993 and 2019, while Antarctica lost about 148 billion tons of ice per year.

•Glaciers retreating: Glaciers are retreating almost everywhere around the world — including in the Alps, Himalayas, Andes, Rockies, Alaska, and Africa.

•Sea level rising: Global sea level rose about 8 inches (20 centimeters) in the last century. The rate in the last two decades, however, is nearly double that of the last century.

•Arctic sea ice: Both the extent and thickness of Arctic sea ice has declined rapidly over the last several decades.

•Extreme events: The number of record high temperature events in the United States has been increasing, while the number of record low temperature events has been decreasing, since 1950.

•Ocean acidification: Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30%.

In short, the question is not whether climate change is happening — direct measurements, paleoclimate records (ice cores, tree rings, ocean sediments), and satellite observations all show it — but how rapidly it is changing and how to address the human-caused greenhouse gas emissions driving it.

Citations (2)

1nasa.govGovernment
Scientific Consensus - NASA Science
Backs: “Yes, climate change is real - this is the established position of the overwhelming majority of climate scientists and every major scientific organization in the world. 1. Scientific consensus is overwhelming. Scientific evidence continues to show that human activities (primarily the human burning of fossil fuels) have…”
2ohchr.orgNot yet classified
The impacts of climate change on the effective enjoyment of human rights
Backs: “government assessment echoed this: "Earth's climate is now changing faster than at any point in the history of modern civilization, primarily as a result of human activities.". 2. The Intergovernmental Panel on Climate Change (IPCC) position. The Intergovernmental Panel on Climate Change (IPCC) has unequivocally…”