There’s been a lot of news lately about extreme weather throughout the world; here in the U.S. the Huffington Post as well as other news sources reported that the past twelve-month period from July 2011 through June 2012 has been the hottest on record. In other news over half of the continental U.S. is in extreme drought conditions.
Gee, I wonder if what all the scientists have been saying about converting all those gigatons of solid and liquid carbon under the Earth’s surface into carbonaceous gases in the atmosphere is influencing our weather?
High temperatures affect a lot of things; people get heat exhaustion, some die. Many populations migrate; some to warmer climates and some to cooler. Bio-rhythms get out of sync, glaciers melt, sea levels rise and something I haven’t read in the tabloids lately – its affect on pollination.
It is well documented that when temperatures exceed 95 degrees Fahrenheit the yields from the three main food crops of the world – corn, wheat and rice – decrease, sometimes dramatically. It’s also true of tomatoes. High temperature kills the pollen and/or desiccates the female part of the flowers; therefore, preventing pollination.
When there is no pollination there will be no grain or fruit.
When corn is in anthesis viable pollen from the tassel must land on a viable silk and travel the length of the silk to fertilize the egg. Every kernel (egg) of corn on the cob has a silk or stigma that has to be fertilized in order to have a fully developed ear of corn.
If temperatures exceed 95 degrees and it is dry during the anthesis of corn then pollination is unlikely to occur; which means no grain.
That’s pretty much the same with rice and wheat and tomatoes. That’s what the science tells us. If this is happening with these four crops can we deduce that it is also happening with other plants?
A major frontier for world food security is agronomic plant breeding that uses every available technology, including genetic engineering to develop crops that better tolerate higher temperatures, less moisture and other pathological issues brought about by anthropogenic global warming.
Thank you for this very informative article. This is the summer of reckoning and introspection. Just as in the ag fields of Virginia’s Valley, over here on the Western shore of the Chesapeake the heat has influenced ecological rythms. The nettles (jelly fish) showed up in our creek in early June. Over 20 years, this is the earliest they have returned. Our corn in this region has tight curled leaves and browning from the ground up. It looked similar in August last year. Our dogwoods, redbuds and tulip poplar trees are “wilting”. Beech tree leaves actually have scorch along the midveins. When I pick up the hose to water the parched plants I have thoughts regarding the weather we are experiencing. We had similar weather last year, but now I don’t see it as just weather, I see it as climate change. Do we have the water to sustain our crops and natural landscapes?
Hi Judy – to answer your question; no, we do not have enough clean water in the USA to maintain our currently level of agricultural production. I can speak specifically to the area I now live in central lower Michigan. We have had 9 inches of precipitation since January 2012. Our normal rainfall is 30 inches annually. We had 18 inches in 2011. I have large trees beginning to die. The long term prediction is for parts of Michigan to return to grasslands as we cannot support deciduous trees with such low rainfall.
Farmers without irrigation are suffering badly here. Small, limited resource farmers like me do not have a prayer unless we can irrigate. We are down to 20 acres now having lost an 80 acre parcel in 2011. Without irrigation, I cannot feed my family on 20 acres! I could not make a profit on the 80 without supplemental water so it was a blessing to lose it. Even the weeds are dying in areas on our farm that do not get any water.
Corn and soybeans are a typical rotation now in this area. Pastures and hay fields have been plowed up to plant more row crops leaving many fields bare of any vegetation for long periods. There is nothing to collect the morning dew that will evaporate into rain clouds.
Bobby – our focus to stabilize the climate should be on the soil, not engineering crops to withstand or adapt at this time to a changing environment. We already have the seeds that are capable of growing in harsh environments with low inputs that have evolved over thousands of years. And, how can we predict what the future climate will be? I use Painted Mountain corn as an example of a highly adaptable corn crop. I have stressed the heck out of mine this year as an experiment and it will produce a good crop this year. It has pollinated very well in high temperatures where my sweet corn has not.
Keeping our soils covered should be priority one. We need to do all we can to cool down the soil on the earth. Good vegetation will collect the morning dew and evaporate into rain clouds. I was reminded of this last week while planting my late crops. I had a strip of bare sandy loam soil not yet planted that was close to 110 degrees. I could not walk on it without burning my bare feet. I was concerned the seeds being planted would cook before they sprouted. Right next to it, the soil covered was 30 to 40 degrees cooler and did not reflect any solar energy back into the atmosphere.
As a conservationist, I am deeply concerned about conserving native and indigenous seeds and not having them “corrupted” by mutant genes from GMO crops. They require fewer inputs and are not monopolized to where people cannot save and select the seeds for the next crop or go into debt to buy them or the extra inputs to grow them.
I have just read the posts on the JMU hillside project and I want to thank you for developing this community of people caring for the environment. I am a “wildlife farmer” rather than an agro-farmer, but the effects of warming temps affects us all.
Thanks again and I look forward to your next blog entry.
This a test. We’ll see if it shows up.
Well, it showed up immediately.
The Dickcissel situation at Wheatlands is not looking good from a pasture maintenance standpoint. There are still (July 24) young being fed in the nest and the thistles are shedding seed and the burdock is making burrs. From a haymaking standpoint the four sections I have reserved for the nesting grassland birds are degraded. I tried to turn the cows into one of them yesterday and they won’t go in it even though there is good grass there under the canopy of thistles and other weeds.
There are probably about a dozen Dickcissel nests on this farm because of the overmature stands in those four sections and in the CREP zones. It’s hard to say if the CREP zones alone would have been large enough to attract what appears to be a breeding colony (they are not colonial nesters but they are close interacting neighbors who probably know and interact with one another as individuals year round).
What these birds appear to be saying is that to have nesting Dickcissels (in the years they chose to “irrupt”) an eastern farmer must forgo use of some of his pasture and hay ground for the entire growing season. Worse, he/she must permit the thistles and burdock to mature and go to seed — not so great for pasture quality or neighborly relations.
You’re the go-to program guy, Bobby, so how are we to work this thing? The DickcisseLs are
really important grassland birds, they are being treated badly (purposely poisoned as ag pests) on their wintering grounds in Venezuela, and they appear to be losing ground in the western part of their breeding range in the short grass prairies due to drought and fire.
As such they may become indicator species for climate change; which, while global, is having some very specific local effects.
If the Dickcissels, being late nesters, are to compensate for their western range losses by expanding into the scant grasslands available to them in the east, we are going to have to have some sort of program to support those land owners who chose to devote some grassland to the Dickcissels’ use. What’s your thinking?
Here is what I tried earlier to post regarding your climate change theme and the
I had a conversation last summer with Kenn Kaufman with whom I worked on some video projects. He suggested that the Dickcissels are pressured by drought and fires in the western part of their breeding range and that could account for their appearance eastward in 2011. This year there are more drought and fires in the west and more dix in the east. Although we are not suffering here, NC is burnt up, and as I see the wx moving, there are some systems picking up Great Lakes moisture and curving around to the southeast. (You can watch the movement on http://radar.weather.gov/ ). So in 2011 and 2012 there have been drought and fires in the west and dix here. If that happens another year
(not necessarily next year) I would say that suggests a trend and that the Dickcissel may become an indicator species for climate change.
Dix are obligate grassland breeders, they have always been associated with the prairies, and prairies are grasslands only because of the combined grazing by ungulates and fire set by humans to suppress the succession which would otherwise occur. I think there is reason to believe that at some radius from Buffalo Gap that has also been historically correct. So perhaps there is some genetic memory carried by the dix which suggests that periodically, particularly in times of stress, they revisit their premier opportunity for access to grassland nesting habitat in the east. That means Swoope. In her range maps in the 1980 edition of Peterson’s Eastern Birds Virginia Peterson shows Swoope and another disjunct eastern
breeding enclave around Frederick, Maryland which might have a comparable historic
association with bison- (or other megafauna) and human- maintained grasslands, a process which might go back to post-glacial times.
This year I have reports from friends in Rockbridge Co and as far north as central PA of occasional Dickcissels. They are not occasional in Swoope; we have a crude census of 15 territories on 160 acres on this farm. My thesis is that the concentration around Buffalo Gap suggests historic grasslands. The abundance of other grassland birds (Bobolinks, grassland sparrows) also supports it although I don’t have a way to compare Swoope populations with those in other localities as we do with Dickcissels.
A problem, as you site, is that the dix nest late and get suckered into starting nests on hay ground which are destroyed shortly thereafter. This year the dix arrived on June 1. As of today (July 21), they are feeding fledged young at Wheatlands which means they probably have two weeks to go before they flock out of here for Venezuela. Haymaking, thistle control, and time-tested pasture management in the Shenandoah Valley all favor mowing by mid-july if not sooner. That would be more of a problem here than in their western ranges, especially short-grass prairies, because haying is more likely here than in the west. Dickcissels are not programmed to deal with haying and bush hogging and their late nesting makes them more vulnerable than the rest of the grassland cohort. Whether or not they are better off losing a large percentage of their nests here to machinery than dealing with western drought and fires is an open question. I like your idea of a program to support a delay in cutting for their benefit; otherwise their nesting and recruitment opportunities may continue to shrink with the loss of the western breeding range. As you know they are persecuted (poisoned) on their wintering grounds in VZ for crop depredation, so they can use a little help.
Thanks for the admirable work with your blog. Feel free to post this because the blog has not accepted my posts.
Robert Whitescarver email@example.com
Hi Professor Whitescarver,
This post was interesting about how anthropogenic climate change is affecting agricultural crops. I’ve been working in Shenandoah National park for the past 4 months and I’ve seen and heard the effects on the wildflower plants here in the park. Many wildflower enthusiasts have come to park asking what has happened to their favorite species of wildflower. Either the species are not as common as they used to be or are not around at the time they should be, both of which are due to climate change. So it is fair to say that it is not only agricultural plants that are going to be affected.
On another note, I have met many visitors from places like Illinois, Iowa, and other states that have been affected by the summer drought. They have all talked about tapping into reserves and drought insurance to maintain their livelihoods. I believe developing drought and temperature resistant crops would help these farmers in the future. There is only so much you can do for the soil but when the air is too hot we need new, better initiative. These farmers would absolutely benefit fiscally from a GE crop if this seasonal heat trend were to continue. Also the price of food would remain low for everyone if we did not have to use reserves (or use corn for ethanol fuel!).
I am amazed at the number of people who have bought into the whole genetic engineering processes. Farmers will benefit most by reducing the amount of row crops in their rotation and diversifying their operations, getting livestock back out on pasture and by returning hay and pasture to the rotation. Mutating crops artificially and strapping farmers with excessive debt and inputs to pay for designer crops will not keep food artificially cheap as it is now. We all pay with environmental degradation when the soil washes down the hill and into our watercourses. We cannot mutate our way out of this dilemma. The key to sustainability is caring for the soil first and sequestering carbon to build soil life and organic matter content that will also help mitigate against the effects of drought. I am breeding drought resistant corn with parents from open pollinated varieties grown by the Incas and farmers in the US from the mid-1800’s as well as other varieties grown by Native Americans in the US.
Thanks for this post professor, I honestly didn’t know that high temperatures affected pollination so drastically. I think it’s great to know such information rather than neglect it in order to focus on other things–we can aim to simultaneously improve our conditions with our farmland. This is just another example of the effects humans have on their environment and how we need to work to achieve a certain goal to stabilize the climate and try to cut back on GHG emissions–it will only lead to further destruction if we do not. It I find it irritating to realize that “when temperatures exceed 95 degrees Fahrenheit the yields from the three main food crops of the world – corn, wheat and rice – decrease, sometimes dramatically,” I hope we can work to find a solution to this problem.
This post has shown some serious effects of the extreme heat of summer that I have never seen reported. With all the greenhouses agriculture uses to grow crops and other plants, I would say the average American thinks that plants love heat exponentially, but this is by far not the case as illustrated by this posting. The scary thing is that because of positive feedback loops that exist and the persistent and growing amount of carbon being pumped into the atmosphere by the machine known as modern society, there is no telling if the extreme weather is a process that can realistically be slowed down or reversed through human remediation. I think plant breeding and genetic engineering of heat and drought resistant crops could be a dangerous process in giving corporations more power, but the only way to establish a consistent agricultural yield.
I did know that there are some summer crops that don’t do well when it gets too hot but I had no idea the heat affects pollination. Nor did I know that it specifically effected corn, wheat, and rice. We can’t afford to decrease the yield of these crops so drastically. This is yet another reason we need to take action in reducing our impact on global climate change.I agree that plant breeding and genetically modifying plants to withstand drought and excessive heat waves would be a good step towards preventing this lack of pollination. Chris is correct that this may give corporations more power over the common farmers but it might be necessary if the three main crops can’t survive the heat. World hunger is already a problem and our planet isn’t getting any cooler.
This post implies some serious consequences of the climate change currently happening in the world. It makes me think not only about domesticated crop plants but also species found in natural habitats. If the heat can prevent corn from pollinating, then how many natural species could this effect? Climate change could force many species out of their natural range, changing the species make up of ecological communities all around the world. Without metapopulations of species in less effected areas or a diverse genetic make up that helps a species adapt to change, many species may even face extinction.
This is an interesting post Dr. Whitescarver. I thought it was interesting how the pollination can be affected by high temperatures. I wonder how the high temperatures can easily kill the pollen and/or desiccate the female part of the flowers. Even though a lot of people are against it, it really is great that we have agronomic plant breeding to help us have food security.
Wow! I didn’t realized how great of an impact global warming was having on pollination. This is a scary thought considering that there are many nations who are already struggling to obtain enough food for their people. If corn, wheat, and rice decrease in yield, food insecurity worldwide is going to increase. This just proves that there is the need for society to embrace genetically engineered crops. It is unfortunate that there are currently many people against genetically engineered food. For example, there are many environmentalists and organic farmers who do not agree with GE. They need to realize that GE might be the only way we can meet the world’s need for food without drastically harming the environment.
Maryann, good comment!
This problem is everywhere! In Australia they have been suffering from drought for almost twelve years now and it has taken a serious toll on the farmers in the Murray-Darling Basin (south-eastern Australia). This is where they do the majority of their agriculture and the weather has been so unpredictable that their water resources are really starting to suffer now. Global warming is an issue that now more than ever needs to be taken into consideration.
In ISAT we have been taught all about the risks of climate change due to the release of CO2 in to the atmosphere, however most cases we cover deal with weather patterns, sea level rises due to glacial melting. I don’t thing we have ever covered how plants are affected by the ever increasing temperatures. Also I almost feel a little let down that I was unaware that each corn kernel had a silk which is the mechanism by which the plant is fertilized. It is upsetting that I went on so long in life being ignorant to these simple but important facts. It seems apparent that if we don’t get a handle on things now, issues in the future could be more devastating than the average person realizes.
Mark, don’t feel bad, most people don’t know about the corn kernel silk relationship. Yes, we need to get our CO2 levels down to – 350ppm
I knew that rising temperatures would have a variety of consequences but I never even thought of the affects on pollination. I never knew that “If temperatures exceed 95 degrees and it is dry during the anthesis of corn then pollination is unlikely to occur” this is a scary fact. If this is true for corn then it could be true for many other plant species. If plant pollination is seriously affected by high temperatures then the future will see a serious problem with agricultural yields. Temperatures will continue to rise if we don’t change the way we all live our lives. We need to reduce our pollution of greenhouse gases and start using other sources of energy besides coal and oil.
In my opinion, that is a litlte fatalistic. Humans have always adapted to their climate. Yes, crops will fail. We have to adapt. Plant crops that grow in the new climate. Learn to rely on different sources of food. Learn to grow food in other ways. (i.e. hydroponics gardens powered by solor or wind generated energy. We can’t stop adapting now.It is noteworthy to remember that weather statistics have only been officially recorded for a litlte over a hundred years. In the earth’s lifespan, that is very litlte time to base any decision. Just because the climate is warming now, does not mean that in the general scheme of things, this isn’t normal. Having said that, there is no doubt that human activities have affected the earth and climate. But human existence has always had an affect on that to some extent. Meteorologists, geologists and archaeologists know that the worlds climates fluctuate from time to time. They also know that the climate will warm and cool again one day (maybe that’s happening now). They also know that when the globe warms, the earth then corrects itself, leading into an ice age. After the ice age subsides, the earth is then cleansed.In the end, I do believe that the human race is in for a rude awakening and there is no doubt that people will die. Humans, however, have survived one ice age and with all of our technological advances, there is litlte doubt that we can survive another. So yes, save the planet, but don’t think for a minute that anyone can stop the inevitable, no matter what we do. Even leaving the planet in-masse will not stop the climate from changing.