00 · IN THREE MINUTES

The answer in three steps

  1. 1Earth has warmed naturally many times, driven by orbital changes, volcanism, tectonics and carbon-cycle feedbacks.
  2. 2Modern warming matches the physics and fingerprints of human greenhouse-gas emissions, while solar and volcanic trends cannot explain it.
  3. 3The current carbon-release rate is far faster than the onset of the , one of the largest warm events in the past 66 million years.

01 · PAST WARMING IS REAL EVIDENCE

Past warming is real evidence

Pollen, ice, corals, sediments and isotopes record climates before thermometers. These archives show that the climate changes when energy balance and greenhouse gases change.

02 · A PRECEDENT DOES NOT IDENTIFY A CAUSE

A precedent does not identify a cause

Forest fires occurred before people, yet a specific fire can still be arson. Likewise, earlier natural warming does not determine what is forcing the modern trend; attribution uses the observed fingerprints.

03 · CARBON CARRIES CLUES

Carbon carries clues

Fossil carbon is depleted in carbon-13, atmospheric oxygen declines as it burns, and CO₂ rises in step with measured emissions. Oceans absorb both heat and carbon, becoming more acidic.

FIG. 02Compare cause and rate, not temperature alone
Two warm episodes can reach similar temperatures through different forcing histories and at radically different speeds.

04 · THE SUN DOES NOT MATCH THE PATTERN

The Sun does not match the pattern

Solar output has not risen enough to explain recent warming. The atmosphere warms near the surface while the stratosphere cools, the pattern expected from added greenhouse gases rather than a brighter Sun.

05 · RATE CHANGES THE COMPARISON

Rate changes the comparison

The PETM released a vast amount of carbon and warmed the planet, but estimates place its onset over thousands of years. A 2016 analysis found its maximum sustained rate below about one tenth of the 2014 human rate.

FIG. 03The answer in three steps
Two warm episodes can reach similar temperatures through different forcing histories and at radically different speeds.

06 · ANCIENT EVENTS ARE WARNINGS, NOT ALIBIS

Ancient events are warnings, not alibis

Past warm periods reveal sea-level, ecosystem and ocean-chemistry responses. They strengthen the reason to expect consequences from carbon release; they do not erase the source of today’s perturbation.

07 · SOURCES AND EVIDENCE

Sources and evidence

The explanation follows the evidence chain below. Links open the original source.

  1. 01
    Anthropogenic carbon release rate unprecedented during the past 66 million years

    Supports a specific claim or evidence boundary used in this article.

    PRIMARY SOURCE ↗
  2. 02
    IPCC Sixth Assessment Report: The Physical Science Basis

    Supports a specific claim or evidence boundary used in this article.

    PEER-REVIEWED REVIEW ↗
  3. 03
    NOAA Paleoclimatology

    Supports a specific claim or evidence boundary used in this article.

    OFFICIAL REFERENCE ↗
CHANGE LOG28 Aug 2026 · First five-language edition; claims, evidence boundaries and visual model checked.