Is climate change real?

Yes

I'll gather the latest scientific evidence to answer whether climate change is happening.

Yes — climate change is real, and that conclusion is supported by overwhelming scientific evidence and agreement among scientific organizations worldwide.

1. What scientists mean by "real"

Scientists distinguish between natural climate variability in Earth's past and the current rapid warming:

•There is unequivocal evidence that Earth is warming at an unprecedented rate. Human activity is the principal cause.

•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.

This is based on over a century of scientific evidence forming the structural backbone of today's civilization.

2. The scientific consensus is overwhelming

There is overwhelming scientific agreement that climate change is real and primarily caused by human activities.

Reviews of published research consistently find:

•More than 99% of climate-related scientific papers support the view that human actions, such as burning fossil fuels and deforestation, are the main drivers of contemporary global warming

•More than 97 percent of climate scientists now attribute recent global warming mostly to human causes, and several analyses even place the consensus above 99 percent

•A 2019 review of scientific papers found the consensus on the cause of climate change to be at 100%

•Multiple studies published in peer-reviewed scientific journals show that climate-warming trends over the past century are extremely likely due to human activities

The body of peer-reviewed science and major scientific organizations state unequivocally that recent warming is real and that human activity is the primary cause.

This position is endorsed by virtually every major scientific body, including:

•18 Scientific Associations joint statement (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."

•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."

•11 international science academies joint statement: "Climate change is real... there is now strong evidence that significant global warming is occurring... It is likely that most of the warming in recent decades can be attributed to human activities"

•Intergovernmental Panel on Climate Change (IPCC): "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."

The IPCC, which reviewed more than 14,000 studies, describes human influence as unequivocally caused by GHG emissions from human activities, and media summaries of its Sixth Assessment Report highlighted the headline finding that climate change is "unequivocally" caused by human activities. In 2019, atmospheric CO2 concentrations (410 parts per million) were higher than at any time in at least 2m years.

3. The evidence

A. Temperature records
We know the world is warming because people have been recording daily high and low temperatures at thousands of weather stations worldwide, over land and ocean, for many decades. When different teams (e.g., NOAA and NASA and the U.K.'s Hadley Centre) average these data together, they all find essentially the same result: Earth's average surface temperature has risen by about 1.8°F (1.0°C) since 1880.

B. Multiple independent lines of evidence
In addition to surface station data, we have many different lines of evidence that Earth is warming. Birds are migrating earlier, marine species are moving north, plants are blooming earlier, mountain glaciers are melting worldwide, snow cover is declining, Greenland's ice sheet is melting at an accelerating rate, mean global sea level is rising, and Arctic sea ice is declining rapidly.

C. The human fingerprint
We know this warming is largely caused by human activities because the key role that carbon dioxide plays in maintaining Earth's natural greenhouse effect has been understood since the mid-1800s. Since 1800, the amount of carbon dioxide in the atmosphere has increased from about 280 parts per million to 410 ppm in 2019. We know from both its rapid increase and its isotopic "fingerprint" that the source of this new carbon dioxide is fossil fuels, and not natural sources like forest fires, volcanoes, or outgassing from the ocean.

Finally, no other known climate influences have changed enough to account for the observed warming trend. Taken together, these and other lines of evidence point squarely to human activities as the cause of recent global warming.

Human activities have - "unequivocally" according to the IPCC - caused global warming, mainly through greenhouse gas emissions.

In short, while Earth's climate has changed naturally in the distant past, the current warming is happening much faster, matches the physics of greenhouse warming, and cannot be explained by natural factors alone.

Citations (3)

1nasa.govGovernment
Climate Change - NASA Science
Backs: “Scientists distinguish between natural climate variability in Earth's past and the current rapid warming: There is unequivocal evidence that Earth is warming at an unprecedented rate.”
evidence, article, points to yes. Claim: There is unequivocal evidence that Earth is warming at an unprecedented rate, with human activity the principal cause.
2nasa.govGovernment
Scientific Consensus - NASA Science
Backs: “There is unequivocal evidence that Earth is warming at an unprecedented rate. Human activity is the principal cause. 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…”
evidence, article, points to yes. Claim: Scientific evidence shows human activities, primarily burning fossil fuels, have warmed Earth's surface and ocean basins, impacting climate.
3climate.govGovernment
What evidence exists that Earth is warming and that humans are the main cause?
Backs: “We know the world is warming because people have been recording daily high and low temperatures at thousands of weather stations worldwide, over land and ocean, for many decades. When different teams (e.g., NOAA and NASA and the U.K.'s Hadley Centre) average these data together, they all find essentially the same…”
evidence, article, points to yes. Claim: Temperature records from thousands of weather stations, averaged by NOAA, NASA and Hadley Centre, show about 1.0°C warming since 1880.