Great Lakes Vineyard Confronts Climate Change

There are two aspects of the recent presentation Great Lakes Vineyard Confronts Climate Change that need to be considered: scare mongering by anecdote and Bandolini’s BS principle. It is a sad commentary on the media today that this presentation had so little substance other than anecdotal “evidence” that climate change is adversely affecting vineyards in the Great Lakes. Showing that the presumptions in the presentation are weak is a perfect example of Alberto Brandolini’s BS principle: “The amount of energy necessary to refute BS is an order of magnitude bigger than to produce it.”

Anecdotal Evidence

Angelica A. Morrison’s newscast claims that “Problems from disease, like powdery mildew, and pests arise when temperatures extremes become the new way of life.” Interviewing a farmer who shows her some diseased plants purportedly shows the effects of the climate change in western New York. The evidence for extreme weather change is the farmer’s recollection: “We’ve had a very mild winter [in 2016] so almost everything survived,” he said. “But prior to that, the winter of 2014 to 2015, were extremely cold temperatures that I’ve never seen before. “And it killed a lot of vineyards that in the past we’ve had success with. We’ve done a lot of replanting and we try to choose varieties that can survive the winter.”

The presentation explains that the vineyard in question is in the Lake Erie Concord Grape Belt, which starts in western New York and extends to Pennsylvania and goes on to note that the area depends on Lake Erie to moderate temperatures. “The lake is supposed to be our great protector,” says Tim Weigle of the Cornell Cooperative Extension’s Lake Erie Regional Grape Program. The presentation notes that “Weigle, who advises grape farmers and works with them on managing their crops, says the lake doesn’t freeze over like it used to. When temperatures are prematurely warm, crops come out of dormancy, making them vulnerable to frost. ‘If the lake freezes then we don’t have those problems, but since it hasn’t been freezing all the time, we have run into more problems with frost and freezes,’ he says.”


There are two claims in this presentation. The first is that in the winters of 2014 and 2015 there were extremely cold temperatures that the farmer has “never seen before”. The second is that when Lake Erie freezes over temperatures don’t warm up prematurely so crops are not damaged coming out of dormancy before the last killing frost of the season.


In order to prove or refute the claims in this presentation complications immediately arise. There is no question that there is a warming trend in this region but what causes winter damage in the first claim? If damage occurs because of the lowest temperature of the year that can be checked easily but if it is the duration or number of days below some threshold temperature, the analysis gets more complicated quickly. For the second claim, if the problem is a period of temperatures so warm and so long that dormancy is broken followed by a killing frost the trends analysis for that is even more complicated.

The second claim confuses me. In particular, this statement “If the lake freezes then we don’t have those problems, but since it hasn’t been freezing all the time, we have run into more problems with frost and freezes”. Lake Erie moderates air temperatures because the seasonal lake temperature lags behind the seasonal air temperature. As a result, in the fall frosts don’t occur as early because the warmer lake tempers the freezing air. In the spring there is moderation for warming and cooling. The lake is generally cooler and slows the plants coming out of dormancy but also protects them if a cold snap comes along because its temperature is above freezing. My problem with the presentation statement is that those effects are eliminated when Lake Erie freezes over. When Lake Erie freezes over downwind air temperatures are not moderated by a source of above freezing water and as a result temperatures are not moderated and, most visibly, the Lake Erie lake-effect snow machine is cut off. Therefore, the moderating effect on frosts and freezes should be enhanced if the lake does not freeze over.


The New York Climate Change Science Clearinghouse is described by its supporters as “a regional gateway to data and information relevant to climate change adaptation and mitigation across New York State. It provides climate science data and literature and other resources for policy-makers, practitioners, and the public, to support scientifically sound and cost-effective decision making”. I tend to be a little more cynical about its contents because it is biased towards alarmism. However, it does provide anyone with easy access to relevant climate data.

The Climate Data Grapher – Station Temperature includes annual average minimum temperature for Fredonia, NY in addition to the other following parameters:

  • Daily maximum temperature (F)
  • Daily minimum temperature (F)
  • Daily average temperature (F)
  • Growing degree day accumulation, base 50 F
  • Heating degree day accumulation, base 65 F
  • Cooling degree day accumulation, base 65 F
  • Counts of days with max temperature above 90 F
  • Counts of days with max temperature above 95 F
  • Counts of days with max temperature above 100 F
  • Counts of days with min temperature below 0 F
  • Counts of days with min temperature below 32 F
  • Growing season length (days)

All of these parameters show what we would expect in a warming climate: daily minimum, maximum, and average temperatures are increasing, cooling degree days, growing degree days and growing season length are increasing, heating degree days are decreasing, the counts of warm days are increasing and cool days are decreasing.

With respect to claim number one that during the winters of 2014 and 2015 there were extremely cold temperatures that the farmer has “never seen before”, we can check the claim by looking at the count of number of days below 0 F. Unfortunately the Fredonia monitoring site stopped operating in 2011 so I used the nearby Buffalo airport site. In 2014 there were six days of below zero temperatures and in 2015 there were 12. In 1979 there were 11 days and looking back there is nothing that unusual about six days that suggests “never seen before” is verified. In fact between 1976 and 1985 there was only one year that was below six days.

Unfortunately, none of the parameters on the Climate Data Grapher can be used to necessarily support or refute the second claim about ice cover and dormancy. A graph of annual maximum ice cover for Lake Erie (available from the NOAA Great Lakes Environmental Research Lab) does support the claim that the lake does not freeze over as much as in the past but as is the case with readily available temperatures it may be the duration and timing of ice cover that affect crop dormancy.

As I explained above I don’t think ice cover affects dormancy but to determine if there is a trend in dormancy that analysis is a bigger deal than I can handle. First you would have to determine the conditions that break dormancy: temperature and duration of temperature above some threshold. If the potential effect is exacerbated by frozen ground that has to be included.  Daily maximum and minimum temperature data are readily available but you would need to develop a program to analyze that data to determine the annual end of dormancy and the date of the last killing frost. If you can show that the end of dormancy is coming earlier in the year and the date of last killing frost is not also coming earlier that would support the claim. If the date of the last killing frost is also coming earlier then that would not support the claims. More importantly, would be to see how often a late frost caused problems with plants historically.


This presentation illustrates problems with the media relative to climate change reporting. This furthers the narrative that climate change effects are happening now for the public who has neither the time nor expertise to evaluate the claims. I heard it on NPR – it must be true.   It is a sad commentary on the media that this presentation had so little substance other than anecdotal “evidence” that climate change is adversely affecting vineyards in the Great Lakes. On the other hand if anyone wants illustrations of two of my pragmatic environmentalist principles it offers vivid examples. Clearly this is a sound bite environmental news report and refuting its baloney took at least an order of magnitude more work. If you wanted to support or refute the dormancy claim it would be another order of magnitude of effort.

Author: rogercaiazza

I am a meteorologist (BS and MS degrees), was certified as a consulting meteorologist and have worked in the air quality industry for over 40 years. I author two blogs. Environmental staff in any industry have to be pragmatic balancing risks and benefits and ( reflects that outlook. The second blog addresses the New York State Reforming the Energy Vision initiative ( Any of my comments on the web or posts on my blogs are my opinion only. In no way do they reflect the position of any of my past employers or any company I was associated with.

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