How e-time relates to half-life

by Dr. Ed Berry

(editing in process)

The cool thing about e-time is it relates to half-life that the public understands. Here are the formulas:

e-time = half-life * 1.4428                                                                (4)

half-life = e-time * 0.6931                                                                (5)

Now, let’s describe how to measure half-life.

Recall the bucket analogy we talked about above.

Put a cork in the hole in the bucket, then fill it with water. Mark the water level and half the water level. Get out your stopwatch. Pull the cork out and record the time it takes for the water level to reach the half-level mark. That’s half-life.

The bucket of water is an analogy to help you understand the concept of half-life. But I must warn you not to carry this analogy too far because water that flows out of a hole in the bottom of a bucket does not follow equation (1). But it’s visually close enough to use for teaching in a written document like this one.

Here’s what we learn from this analogy.

If we increase the hole size at the bottom of the bucket, water flows out faster, decreasing the half-life, e-time, and balance level, and vice versa.

This is enough to understand the meaning of CO2’s atmospheric half-life.

IPCC says the e-time for CO2 to flow out of the atmosphere “is about 4 years.”

IPCC’s natural carbon cycle data shows this e-time is 3.5 years. Equation (5) shows that this e-time equals the atmospheric half-life of CO2, about 2.4 years.

The key point is IPCC’s own data say the half-life of all CO2 in the atmosphere is about 2.4 years.