Debunked: False Claims About CO₂ Measurement and Climate Model “Scam”

An X post that has more than 204,000 views is spreading misinformation about climate science, claiming that it’s “impossible to measure carbon dioxide from human activity” and calling climate change “a computer modelling scam.”

The post by handle @PeterDClack, says “Its impossible to measure carbon dioxide from human activity; only guesswork. Climate change is a computer modelling scam, aided by a fake media, google, frauds & mass hysteria. The IPCC used every trick in the book, then Trump came along. Now they’ve all gone quiet.” 

Its impossible to measure carbon dioxide from human activity; only guesswork. Climate change is a computer modelling scam, aided by a fake media, google, frauds & mass hysteria. The IPCC used every trick in the book, then Trump came along. Now they've all gone quiet. pic.twitter.com/u7JMu7kFfk

— Peter Clack (@PeterDClack) March 15, 2025

Here is a detailed fact check on the issue. 

CLAIM 1: “It’s impossible to measure carbon dioxide from human activity; only guesswork.

FACT: It is possible to measure CO₂ from human activities with high precision. Scientists use carbon isotopes, emissions inventories, and atmospheric measurements to distinguish fossil fuel emissions from natural sources.

1. Carbon Isotopes Analysis:

Carbon comes in different forms, or isotopes. The most relevant are carbon-12 (¹²C), carbon-13 (¹³C), and radioactive carbon-14 (¹⁴C).

Fossil fuels are devoid of ¹⁴C because they have been buried for millions of years. When burned, they release CO₂ with a distinct isotopic signature.

Scientists detect these signatures in the atmosphere and can trace the proportion of CO₂ that comes from fossil fuel burning.

2. Global Carbon Budget Accounting:

• The Global Carbon Project (GCP) annually publishes detailed emission inventories, accounting for CO₂ released from fossil fuels, cement production, land-use change, and more.
  
• These estimates are based on energy consumption data, industrial activity, and land cover change. They are cross-checked with direct atmospheric CO₂ measurements from monitoring stations around the globe.

3. Atmospheric Monitoring:

Organizations like NOAA and Scripps Institution of Oceanography have been measuring atmospheric CO₂ levels since the 1950s (e.g., Mauna Loa Observatory).

The steady rise in CO₂ matches the timing and scale of fossil fuel use, not natural variability.

Volcanoes, wildfires, and oceans also emit CO₂, but these are part of a long-term balanced natural cycle. The sharp rise in recent decades is directly linked to human activity.

Volcanoes emit large amounts of CO₂

CLAIM 2: Climate change is a computer modelling scam.

 FACT: Climate models are scientific tools based on the laws of physics, chemistry, and biology. They simulate how Earth’s atmosphere, oceans, ice, and land interact under various scenarios.

1. How Climate Models Work:

Climate models use mathematical equations to simulate energy and matter flow through Earth’s climate system.

Inputs include greenhouse gas concentrations, solar radiation, aerosol levels, and land use.

They’re not designed to predict daily weather, but rather long-term trends (e.g., global temperature rise, ice melt, sea level rise).

2. Validation Against Historical Data:

Climate models are tested by running them backward in time to see if they can accurately recreate historical climate conditions.

A key study by Hausfather et al. (2019) reviewed 17 climate models published between 1970 and 2007 and found that their temperature predictions closely matched observed global warming.

3. Wide Scientific Consensus and Transparency:

Climate models are developed by independent institutions worldwide, such as NASA, IPCC, Met Office UK, and NCAR USA.

All model assumptions, equations, and data inputs are public and peer-reviewed.

Results are published in reputable journals and subjected to global expert review, especially when included in IPCC reports.

4. What Models Have Successfully Predicted:

Climate models have successfully predicted many key trends in Earth’s climate system, confirming their reliability. One of the most accurate forecasts has been the rise in global surface temperatures. Models from the 1970s onward, including those used by NASA and the IPCC, closely match the observed warming of about 1.2°C since pre-industrial times.

Another success is the decline in Arctic sea ice. Models predicted that as greenhouse gases increased, polar regions would warm faster—a phenomenon known as Arctic amplification. Satellite data confirms that Arctic sea ice has shrunk dramatically, especially since the 1980s.

Models also correctly anticipated increases in extreme weather, including more intense heatwaves, heavier rainfall, and longer droughts in some regions. They have shown the pattern of warming occurring more over land than oceans, and more at night than during the day.

In terms of sea-level rise, models predicted both thermal expansion of oceans and melting of land ice—both now observed globally.

Lastly, ocean acidification, caused by CO₂ absorption, was projected and later confirmed by field measurements.

These successes demonstrate that climate models are valuable scientific tools, not just for understanding climate change, but for preparing societies for its impacts.

References:

https://earthobservatory.nasa.gov/features/CarbonCycle

https://www.globalcarbonproject.org

https://gml.noaa.gov/ccgg

https://www.ipcc.ch/assessment-report/ar6

https://www.giss.nasa.gov/research/features/202001_accuracy

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GL085378

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