Global temperature rise is driven not by annual emissions in isolation, but by the cumulative total of carbon dioxide added to the atmosphere. This relationship is well established: each additional billion tonnes of CO₂ contributes a small but persistent increase in global average temperature.
A widely used estimate places this effect at approximately 0.00045 °C of warming per billion tonnes of CO₂ emitted (equivalent to 0.45 °C per 1000 GtCO₂).
As shown in the previous section, improving forest carbon measurement using LiDAR could avoid the mis-accounting of approximately 76 billion tonnes of CO₂ over a 50-year period.
Applying the established relationship between cumulative emissions and temperature rise:
This is not a projection of temperature reduction, but a reduction in committed future warming. This is warming that would otherwise have been locked in by excess emissions allowed under uncertain accounting.
At first glance, 0.03°C appears negligible. In everyday terms, it is imperceptible. In climate terms, it is not. As the remaining margin to 2°C shrinks, each hundredth of a degree carries disproportionate risk. Small increments determine whether thresholds are crossed or avoided.
Global climate risk is defined at the margins:
We are already at approximately 1.4°C. This means we only have 0.6°C left until 2°C. We alone could be responsible for assuring 5% of our remaining climate budget.
Climate impacts do not scale linearly with temperature. Near critical thresholds:
In this regime, preventing 0.03 °C of warming is not about comfort. It’s necessary to reduce the probability of irreversible change.
Crucially, this avoided warming does not depend on:
It arises purely from improved precision in how the Earth’s largest natural carbon sink is measured.
In a constrained climate system, the difference between staying within limits and exceeding them increasingly depends on measurement accuracy, not just ambition.
Understanding the physical significance of avoided warming allows us to ask the next question: What is the real-world cost of each fraction of a degree, and what is the value of preventing it?
That question is addressed next.