We have always had climate change, and until the Sun incinerates the Earth, always will. Today’s warming is unprecedented only if you abuse the word’s meaning by using qualifiers such as “unprecedented in the last sixty years.” Recent global warming is unprecedented only since 1950: warming from 1910 to 1950 (before large human-caused increases in CO2) was 0.5°Celsius; since 1950 total warming was only 0.4°C, including 0°C the past fifteen years.
Unprecedented the past 1,000 years? The Medieval Warm Period was 1°C warmer. Two-thousand years? The Roman Warm Period was 2°C warmer. Four-thousand years? The Minoan Warm Period was 3°C warmer. Ten-thousand years? The Holocene Climatic Optimum was the longest warm period since the end of the Ice Age, and slightly more than 3°C warmer. The past 125,000 years? The Eemian Climatic Optimum was almost 4°C warmer.
A letter last week used theories to define climate change terms, but omitted supporting observations. It’s OK to say that something could cause something, but if it doesn’t a new theory is demanded. Theoretically, doubling atmospheric CO2 could raise global temperature 1.22°C, but while CO2 has climbed steadily for over sixty years, global temperature has not. In fact, the world added roughly 110 billion tons of carbon to the atmosphere between 2000 and 2010, about a quarter of all the CO2 put there by humanity since 1750, yet global temperature has been flat the last fifteen years.
The letter writer cited a “change of weather patterns as compared to our stable Holocene past.” Only climate history ignorance could inspire such a statement. Our Holocene past is filled with changing weather patterns; reading Dr. H. H. Lamb’s excellent climatic histories would dispel ignorance of an unstable Holocene.
When facts disagree with theory, alarmists want to change the facts. Science can't work that way.