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SCIENCE

The Claim

Human activities, especially burning fossil fuels and land-use change such as deforestation, are altering the global carbon cycle by increasing atmospheric carbon dioxide concentrations.

Verified by Lenz ·

The Short Version

The evidence firmly supports this statement. Multiple authoritative scientific assessments and direct atmospheric measurements show that burning fossil fuels and land-use change have raised atmospheric CO2 and altered the global carbon cycle. Natural sources of CO2 exist, but they do not explain the sustained modern increase, which is attributable to net human emissions.

Caveats

  • Natural CO2 sources such as volcanoes and wildfires are real, but they are not sufficient to explain the long-term atmospheric increase observed since the industrial era.
  • Land-use change contributes meaningfully, but fossil-fuel combustion is the dominant source of human-caused CO2 increase in the modern period.
  • Some cited items are secondary or non-authoritative summaries; the core conclusion rests on primary assessments and measurement programs such as IPCC, NOAA, NASA, EPA, and the Global Carbon Project.

The Receipts

  1. Climate Change 2023: Synthesis Report

    IPCC

  2. Climate Change 2021: The Physical Science Basis

    IPCC

  3. The Causes of Climate Change

    NASA Science

  4. Carbon Dioxide - Earth Indicator

    NASA Science

  5. Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990–2021, Chapter 1: Introduction

    U.S. Environmental Protection Agency

  6. Climate change: atmospheric carbon dioxide

    NOAA Climate.gov

  7. Scientific Consensus: Earth's Climate Is Warming

    NASA Science

  8. Global Carbon Budget 2024

    ESSD / Copernicus

  9. Trends in Atmospheric Carbon Dioxide

    NOAA Global Monitoring Laboratory

  10. Fossil fuel CO2 emissions hit record high in 2025

    Global Carbon Project

+ 17 more sources — see the full list on Lenz

Filed Under

Carbon CycleCarbon DioxideDeforestationfossil fuels

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