In a late February (2017) interview on a U.S. news program, mechanical engineer Bill Nye claimed that the settled science says humans have been warming the planet at a rate that is unnaturally and “catastrophically” fast since the year 1750 .
“It’s a settled question. The speed that climate change is happening is caused by humans. Instead of climate change happening on timescales of millions of years or 15,000 years, it’s happening on the timescale of decades, and now years. … Humans are causing it [climate change] to happen catastrophically fast. [Without human activity], the climate would be like it was in 1750.”
When pressed to identify the signature change affirming this rapid human-caused acceleration, Nye immediately cited viticulture evidence, or grape-growing practices in England and France.
“Britain would not be very well suited to growing grapes as it is today [if not for human activity]. French winemakers would not be buying land to the north, as they are now [if not for human activity].”
Apparently Bill Nye believes it is quite unusual to grow grapes in England. Or maybe he believes that this has never happened before given his perceptions of the unprecedentedly fast pace of climate change since 1750. Perhaps he doesn’t realize that grape vineyards have been growing in England for thousands of years, or that grape harvesting occurred 100s of kilometers further north than it does today as recently as during the latter stages of the Medieval Warm Period (~1100 to 1300 A.D).
Considering how very sensitive grapes are to climate conditions, and that grapes can only be harvested successfully after ripening in climates that average a specified number of warm days per year, the use of grape harvest dating as a proxy for temperature has long been thought to be both promising and reliable.
Unfortunately for Bill Nye and those who believe modern warmth is exceptional, or that the climate has changed at a catastrophically fast pace since 1750, scientists who use grape harvest dates to reconstruct historical temperatures have not found that modern warmth is either unusual or unprecedented. In fact, grape harvest date evidence suggests the opposite conclusion reached by Bill Nye is more accurate: there is nothing unusual about the modern climate and its “well-suitedness” to grape harvesting. In fact, there were several periods of greater warmth than today (and thus better suitability for grape harvesting) during the multi-centennial (~1400-1900 A.D.) Little Ice Age — which had the coldest temperatures of the last 10,000 years.
In other words, there is nothing unusual, unprecedented, or remarkable — let alone “catastrophically fast” — about either the pace or degree of warmth in the modern climate.
