Is climate change real?

Yes, climate change is real.

There is an overwhelming scientific consensus—supported by more than 99% of actively publishing climate scientists and major scientific organizations worldwide—that Earth’s climate is warming and that this warming is primarily caused by human activities.

The evidence for rapid climate change is robust, diverse, and comes from multiple independent scientific sources:

1. The Key Evidence

•Rising Global Temperatures: The planet’s average surface temperature has risen by about 2 degrees Fahrenheit (1.1 degrees Celsius) since the late 19th century. The vast majority of this warming has occurred in recent decades.

•Warming Oceans: The oceans absorb over 90% of the excess heat trapped in the Earth's atmosphere, leading to rapidly warming water temperatures.

•Shrinking Ice Sheets and Retreating Glaciers: Massive ice sheets in Greenland and Antarctica have lost billions of tons of ice, and glaciers worldwide—from the Alps to the Himalayas—are in retreat.

•Declining Arctic Sea Ice: The extent and thickness of Arctic sea ice has declined rapidly over several decades.

•Rising Sea Levels: Global sea levels rose about 8 inches (20 cm) in the last century, and the rate of rise is accelerating as ice sheets melt and warmer water expands.

•Extreme Weather Events: Globally, we are seeing increases in the frequency and intensity of extreme weather, including prolonged heatwaves, severe droughts, heavier rainfall, and stronger tropical storms.

•Ocean Acidification: As humans emit more carbon dioxide ($CO_2$), the oceans absorb a significant portion of it. This has made the oceans roughly 30% more acidic, threatening marine ecosystems and coral reefs.

2. What is Causing It?

The primary driver of modern climate change is the greenhouse effect.

Earth's atmosphere naturally contains greenhouse gases (like carbon dioxide, methane, and water vapor) that trap heat from the sun to keep the planet warm enough to sustain life. However, since the Industrial Revolution, human activities—most notably the burning of fossil fuels (coal, oil, and natural gas), deforestation, and agriculture—have pumped massive amounts of extra greenhouse gases into the atmosphere.

Historically, scientists relied on computer models to estimate how much heat these gases trap. However, NASA scientists have successfully used direct satellite observations to measure the exact amount of extra heat being trapped in Earth's atmosphere due to human emissions. This represents direct, physical proof of human-caused climate change.

3. How Do We Know It Isn't Just a Natural Cycle?

It is true that Earth’s climate has changed naturally throughout its 4.5-billion-year history due to factors like slight shifts in Earth's orbit and solar activity. However, scientists can tell that the current warming is not natural for several key reasons:

•The Speed of Warming: By studying "paleoclimate" archives (such as deep ice cores, tree rings, and ocean sediments), scientists know that the current rate of warming is occurring roughly 10 times faster than the average rate of warming after an ice age.

•Carbon Dioxide Levels: Carbon dioxide in the atmosphere is currently rising 250 times faster than it did from natural sources after the last ice age.

•The Sun is Not the Cause: If the sun were driving global warming, all layers of the atmosphere would be warming. Instead, satellites show that the lower atmosphere (where greenhouse gases trap heat) is warming, while the upper atmosphere (the stratosphere) is cooling, confirming that the heat is being trapped from below by greenhouse gases.

Citations (7)

1nasa.govGovernment
nasa.gov
Backs: “Yes, climate change is real.”
2wikipedia.orgEncyclopedias and referencequality 0.83
wikipedia.org
Backs: “There is an overwhelming scientific consensus—supported by more than 99% of actively publishing climate scientists and major scientific organizations worldwide—that Earth’s climate is warming and that this warming is primarily caused by human activities. The evidence for rapid climate change is robust, diverse, and…”
3nasa.govGovernment
nasa.gov
Backs: “Rising Global Temperatures: The planet’s average surface temperature has risen by about 2 degrees Fahrenheit (1.1 degrees Celsius) since the late 19th century. The vast majority of this warming has occurred in recent decades.”
4caltech.eduAcademic
caltech.edu
Backs: “The vast majority of this warming has occurred in recent decades. Warming Oceans: The oceans absorb over 90% of the excess heat trapped in the Earth's atmosphere, leading to rapidly warming water temperatures.”
5cbsnews.comNews and mediaquality 0.88
cbsnews.com
Backs: “Warming Oceans: The oceans absorb over 90% of the excess heat trapped in the Earth's atmosphere, leading to rapidly warming water temperatures. Shrinking Ice Sheets and Retreating Glaciers: Massive ice sheets in Greenland and Antarctica have lost billions of tons of ice, and glaciers worldwide—from the Alps to the…”
6cornell.eduAcademic
cornell.edu
Backs: “Extreme Weather Events: Globally, we are seeing increases in the frequency and intensity of extreme weather, including prolonged heatwaves, severe droughts, heavier rainfall, and stronger tropical storms. Ocean Acidification: As humans emit more carbon dioxide ($CO_2$), the oceans absorb a significant portion of it.”
7nasa.govGovernment
nasa.gov
Backs: “The primary driver of modern climate change is the greenhouse effect. Earth's atmosphere naturally contains greenhouse gases (like carbon dioxide, methane, and water vapor) that trap heat from the sun to keep the planet warm enough to sustain life.”