The Partial Observer by Roger Caiazza

On Natural Climate Variability

The rationale for changing New York’s energy system away from fossil fuels in the Climate Leadership and Community Protection Act is the alleged link between climate change and greenhouse gas emissions. This presumes that natural climate variability is not appreciably affecting the observed recent warming. I think that presumption does not stand up to scrutiny.

The video “Climate the Movie: The Cold Truth” (https://youtu.be/v_NPby_p5Lg) includes a very good description of historical temperatures and CO2 trends. It provides examples why claims that today’s observations indicate unprecedented heat in earth’s history are wrong. Over geologic time scales, temperatures today are not at all unusual and because we are in an ice age, all previous non-ice age geologic epochs were warmer. Over the last 2,000 years there has been a Roman Warm Period and a Medieval Warm Period, and both had temperatures warmer than today. As shown in the following figure, over the last 175 years temperatures have been warming up since the end of the Little Ice Age but carbon dioxide emissions have only risen sharply over the last 75 years. That means that natural climatic variability must have driven all the warming observed prior to 1950.