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.
In the case of anthropogenic global warming, there is a theory (first conceived over 100 years ago) based on well-established laws of physics. It is consistent with mountains of observation and data, both contemporary and historical. It is supported by sophisticated, refined global climate models that can successfully reproduce the climate’s behavior over the last century.
Given the lack of any extra planet Earths and a few really large time machines, it is simply impossible to do any better than this.
Aside: It is usually interesting to ask just what observations or evidence your skeptic would consider “proof” that global warming is caused by rising CO2 levels. Don’t be surprised if you get no answer!
More stories in this series:
(Part of the How to Talk to a Climate Skeptic guide) Objection: Despite what the computer models tell us, there is actually no evidence of significant global warming. Answer: Global warming is not an output of computer models; it is …
(Part of the How to Talk to a Global Warming Skeptic guide) Objection: CO2 levels are recorded on top of Mauna Loa … a volcano! No wonder the levels are so high. (image courtesty of Global Warming Art)
(Part of the How to Talk to a Global Warming Skeptic guide) Objection: The apparent rise of global average temperatures is actually an illusion due to the urbanization of land around weather stations, the Urban Heat Island effect.
(Part of the How to Talk to a Global Warming Skeptic guide) Objection: One hundred and some years of global surface temperatures is not long enough to draw any conclusions from or worry about anyway. Answer: The reliable instrumental record …
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