Today is the longest day of the year in the northern hemisphere, and in California, it has been a real blazer – my laundry was dry after just a couple hours on the line. And so day length is on my mind.
There are two well-known varieties of sweet onions in North America: the Walla Walla sweet, and the Vidalia sweet. Walla Walla sweets originated in eastern Washington, in the northern tier of states, and so they are a “day-long” variety. They need lots of hours of daylight to mature, so they do best in higher latitudes where the summer days are very long. Vidalia sweets originated in Georgia, in the southern tier of states, and so thay are a “day-short” variety – they do best at lower latitudes where summer days are shorter and daylight hours fewer.
In other words, their ideal conditions are determined not so much by different temperatures, but by different day lengths.
Well, if a lot of plants are like this, that could create a problem for climate mitigation. It is very well to plan ahead for a warmer world by planting tree seedlings at a higher latitude than their genetic origins, on the prediction that the future climate where they are planted will resemble the present climate where they originated. But climate change will not affect day length. Even if tropical-type climates extend further north and south than at present, the Tropic of Cancer and Tropic of Capricorn will not move from where they are now. No amount of climate change will alter the day length at a given latitude.
To return to the onions – even if Walla Walla, Washington in the future has a climate like Vidalia, Georgia has now, it will not be ideal for growing Vidalia sweets there, because it will still be a “day-long” latitude. I foresee this being a problem with our climate mitigation efforts.
You have made a valid point. Quite frankly, I don’t notice the solstice. Here in Alaska, the sun is not really setting at this time of year. The sky just dims a bit. It’s still bright enough to use sunglasses at 10:00 p.m. It has been unusually warm lately. And last year. And the year before.
Last week I posted a topic about the influence of geological forces on genes and what you’re pondering here is a scaling up to the realm of cosmic influences.
It makes me wonder if generic research will ever unravel the specific genes of such interactions, such as a latitude gene.
Or are those genes so ancient and pervasive in the genetic ‘programming’ as to be practically impossible to reverse engineer?
And that’s just the genetic component. Pollinators, soil biology, crop ‘pests’…
Humanity, or at least the heavily industrialized version of it that we’ve become, has such a horrible faith in quick, efficient, technical solutions that focus on time frames based on financial markets/political cycles that I find myself forced to call myself an optimist, out of lack of a liveable alternative.
While I completely understand what you’re saying and do not disagree, I think it’s worth mentioning that crops are not necessarily a good indicator of how nature will cope. The crops we grow have been altered over many many generation to be the biggest, the sweetest, the most pest resistant, have the fewest seeds, etc., and as a result usually require more light, more water, better soil, pruning, fertilizing, and so on. What is produced naturally is often smaller, more heat and drought tolerant, less susceptible to frost and cooler growing seasons, requires less time to mature, and germinates more readily. Absolutely there are going to be plants that struggle to adapt, but there will be many that can thrive. To my mind, a much bigger issues is time. The climate is changing far too fast for anything, including us, to adapt.
A lot of our non-human life (Winnipeg, central NA) is dependant on day length for its winter dormant stage. No matter what type of organism. So I have no idea how climate change will affect this life. As I’ve said before, I personally have not noticed any change in climate. Ours is highly variable, with lots of extremes, so it’s hard to discern trends. I suspect in the long term, if the climate is to change, that those genetic cues will cause some problems for overall life. But I agree with @medeajade - crops plants are not a good barometer. And the speed of change is problematic. How Life will cope, is really unknown.
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