Global warming is man-made

27 Sep 2020

We can simply measure our atmospheric temperature over time and notice it is increasing.

The greenhouse effect proven in small greenhouses also operates at global scale.

We also measure and find that the CO2 levels in atmosphere have been increasing over time.

But how do we know for sure that the CO2 in the atmosphere came from burning fossil fuels and not from other sources?

Whenever we ask this question, everyone immediately points to large number of scientists who believe this. This line of reasoning is hardly persuasive.

The most conclusive proof is provided by C-14.

C-14 is created in the upper atmosphere by cosmic rays interacting with Nitrogen atoms. This CO2 mixes thoroughly in the atmosphere in a few weeks which gets absorbed by plants during photosynthesis, which in turn flows through the food chain into humans. So, the atmosphere and the biosphere have about 1 atom of C-14 in 10^12 atoms of Carbon.

Now, C-14 is radioactive with a half-life of 5730 years. So, all C-14 decays over time at that rate into N-14. That effect is the same in atmosphere and biosphere.

Any change of CO2 in atmosphere due to biosphere changes would preserve the density of C-14.

Now fossil fuels are made of very old plant matter. The C-14 in fossil fuels has long decayed and disappeared. When we burn fossil fuels the released CO2 has no C-14. Therefore this dilutes the atmosphere of C-14. This can be measured.

We know how much fossil fuels we burn and how much CO2 we put into the atmosphere. So we can calculate the expected dilution, which matches the measurement.

This then is the proof that global warming is caused by burning fossil fuels.

Many thanks to Pankaj who provided the incentive to learn and write this little explainer.

🙏🏾

Ranga