Articles by Coby Beck

‘CO2 doesn’t lead, it lags’–Turns out CO2 rise is both a cause and an effect of warming

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: In glacial-interglacial cycles, CO2 concentration lags behind temperature by centuries. Clearly, CO2 does not cause temperatures to rise; temperatures cause CO2 to rise.

Answer: When viewed coarsely, historical CO2 levels and temperature show a tight correlation. However, a closer examination of the CH4, CO2, and temperature fluctuations recorded in the Antarctic ice core records reveals that, yes, temperature moved first.

Nevertheless, it is misleading to say that temperature rose and then, hundreds of years later, CO2 rose. These warming periods lasted for 5,000 to 10,000 years (the cooling periods lasted more like 100,000 years!), so for the majority of that time (90% and more), temperature and CO2 rose together. This remarkably detailed archive of climatological evidence clearly allows for CO2 acting as a cause for rising temperatures, while also revealing it can be an effect of them.

There is no proof in science, but there are mountains of evidence

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: Correlation is not proof of causation. There is no proof that CO2 is the cause of current warming.

Answer: There is no "proof" in science -- that is a property of mathematics. In science, what matters is the balance of evidence, and theories that can explain that evidence. Where possible, scientists make predictions and design experiments to confirm, modify, or contradict their theories, and must modify these theories as new information comes in.

Water vapor is indeed a powerful greenhouse gas, but there is plenty of room for CO2 to play a role

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: H2O accounts for 95% of the greenhouse effect; CO2 is insignificant.

Answer: According to the scientific literature and climate experts, CO2 contributes anywhere from 9% to 30% to the overall greenhouse effect. The 95% number does not appear to come from any scientific source, though it gets tossed around a lot.

‘Climate scientists dodge the subject of water vapor’–No, they really don’t

(Part of the How to Talk to a Global Warming Skeptic guide)

Objection: Climate scientists never talk about water vapor -- the strongest greenhouse gas -- because it undermines their CO2 theory.

Answer: Not a single climate model or climate textbook fails to discuss the role water vapor plays in the greenhouse effect. It is the strongest greenhouse gas, contributing 36% to 66% to the overall effect for vapor alone, 66% to 85% when you include clouds. It is however, not considered a climate "forcing," because the amount of H2O in the air basically varies as a function of temperature.