IMMIGRATION DEBATE: Climate change may spur even more migration from Mexico as a result of declining crop yields, according to a new study.
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Climate change's impacts on crop yields may force as many as seven million Mexicans to emigrate to the U.S. over the next 70 years, according to research published July 26 in the Proceedings of the National Academy of Sciences. The study is among the first to attempt to put hard numbers on questions about "environmental refugees" that may be caused by climate change.
"There is a significant response of emigration from Mexico to past climate variations," says atmospheric scientist Michael Oppenheimer of Princeton University, an author of the study. "Climate changes predicted by the global circulation models would cause several percent of the Mexican population to move north [if] all other factors are held constant."
Based on historical patterns of emigration, crop yield and climate change between 1995 and 2005, the researchers project that as much as 10 percent of Mexico's population could be forced to migrate in coming decades. In essence, for every 10 percent reduction in crop yield as a result of climate change an additional 2 percent of Mexicans would emigrate. The U.S. National Research Council (NRC) estimates that every degree Celsius of warming in global average temperatures means a 5 to 15 percent drop in yield, particularly for corn, in North America.
The number of climate refugees could be significant, anywhere from 1.4 million to 6.7 million Mexicans, depending on how much warming actually occurs. The researchers attempted to account for other variables that governed migration in the past—from the passage of the North American Free Trade Agreement (NAFTA) to U.S. border control policy—and isolate the impact of climate change. "For NAFTA, we took special pains to ensure the robustness of the result by comparing Mexican states that were greatly affected by NAFTA with those which were not," Oppenheimer says.
But the study relies on census data to estimate actual emigration, and it assumes that climate change's impact on maize production—for example, via drought—caused migration in the past and will cause it again in future. "Migration decisions, like all livelihood decisions, are about much more than material quality of life," argues geographer Edward Carr of the University of South Carolina, who studies human migration in countries such as Ghana and was not involved in the Mexico emigration research. "What I am seeing in sub-Saharan Africa are very complex patterns in which environmental change is but one of several causal factors."
The growth in those causal factors—from a population boom to reduced economic opportunity in the countryside—has driven the greatest migration worldwide in recent history. As of 2005, roughly three percent of the world's population lived outside their country of birth—the largest proportion ever recorded by the United Nations. And this represents but a small fraction of migration, since the bulk of that occurs within a given nation from rural to urban areas. "Most often international migration is not an option and rural residents migrate to urban areas, contributing to urbanization and urban poverty in developing countries," says sociologist Elizabeth Fussell of Washington State University.
That is certainly the case in Mexico, according to population and migration researcher Haydea Izazola of the Universidad Autónoma Metropolitana-Xochimilco, also not part of Oppenheimer's team for the new study. "The great majority of the rural population who grow maize—rain-fed agriculture—for their own consumption are the poorest of the poor and lack the means to invest in the very expensive and risky migration venture."
In fact, recent trends indicate it is city residents and educated elites who are driving migration from Mexico today, Izazola notes, suggesting a possible shift from the period in this study. That may be because Mexico experienced a severe drought starting in 1994 that persisted throughout this period, making farmers more "susceptible to these climate effects since there was no time to adapt to them," Fussell speculates. "Migration [is] one of several options rural households face when they confront diminishing livelihoods such as a decline in crop yields."
Once that process begins, however, it can be self-reinforcing, as community members share their experience—and any wealth gained in the new country—with folks back home. Regardless, "if our study results are valid, the effect could be significant in many regions" of the world, Oppenheimer argues.
Of course, the worst-case scenario in this analysis ignores the possibility of new crop varieties that maintain (or improve) yields under warmer average temperatures. "How much can we adapt?" asked climate scientist Susan Solomon of the U.S. National Oceanic and Atmospheric Administration at the release of the NRC report on July 16 "Look at corn. Maybe we can choose to grow something else or genetically engineer that corn to make it more robust."
And climate change is not confined to Mexico. Crop yields in the U.S. will likely suffer as well. "People do not move blindly; they move to greater opportunity," Carr notes. "So we should probably be using [these economic and climate] models to examine the impact of future climate change on various migrant-employing sectors of the southwestern U.S. economy."
In fact, that is exactly what Oppenheimer and his colleagues are currently working on next: predicting how crop yields in the U.S. may impact the immigration debate.
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19 Comments
Add CommentSeems we have quite a quandary here. A good many Americans don't believe climate change exists, and they favor the Arizona approach to Mexican immigrants. We may have to pass a law barring climate change, or else decide that Mexican immigrants aren't real. Of course, we could relax our potty-trained control issues and start loving our fellow humans again -- But I doubt that's very realistic.
Reply | Report Abuse | Link to thisWell there's the eight hundred pound gorilla, where can we run to after we have through parasitic planet eating, decimated our garden. And the fuel for the fire of destruction is over population, can we talk yet?
Reply | Report Abuse | Link to thisWhen anyone predicts stuff like this, one should presume that the reader is adding to the end the phrase: "but it would be a good thing". Maybe our diseases of affluence which everyone complains about will suddenly kill off a large number of us and we'll develope a demand for legal guestworkers to the do the manual labor and what manufacturing is left, in which case global warming would have meant more immigration just to replace our losses. Or maybe some oddball climate disaster totally unexpectedly like a particularly severe stretch of volcanism such as has happened in the climatic past, will re-occur and kill the energy poor first and so that will mean climate chance could lower the population of people who even could come here.
Reply | Report Abuse | Link to thisThe point is; once you start to speculate you might as well get interesting, and if history shows us much of anything about our human ability to predict complex natural patters even though we've been watching for millinia, is that it sucks and that it defies our best efforts, as the grecian gods would any expression of hubris.
I speculate that as it becomes more obvious to more people, that the effects of human civilization are calculable, and multiplied by a quantifiable population number hell-bent on exponential growth damn the consequences, it will be more and more likely that someone with the resources will make the ethical choice, of saving life on earth by trimming the fat, and releasing a virus which renders people sterile. Doesn't outright kill anyone, as that would be inhumane, but instead just ensures that within a generations time, the population is reduced dramatically to give life a chance to reset, and find balance once again. ...if it is not beyond hope by then.
Reply | Report Abuse | Link to thisI say this is more likely, because I myself would fund this today, had I the resources. And if it's occurring to me, it's certainly occurring to people whose job it is to do the work.
It will take more that more immigration to convince people to do something about climate change--more like some cataclysmic event. The equivalent of a Katrina hitting New York City or Los Angeles, maybe, or drought in the southwest beyond anything we can imagine today. Of course, it will get blamed on the 'govamint." But then, perhaps, something substantial will get done.
Reply | Report Abuse | Link to thisHotblack:
Reply | Report Abuse | Link to thisI went to university in the 60s. We were talking about population control mechanisms then. Our idea then was to modify existing pathogens that caused sterility to make them less pathogenic and more sterility causing. Things like Chlamydia trachomatis and other STD causing bacteria.
Our attitude to people of a non-scientific background (Except pretty girls of course) was similar to our attitude to cockroaches.
You are not alone my friend. If no-one does it the sixth extinction will take care of matters.
Why assume that the only northward immigration would be from Mexico into the U.S.? Northern Mexico and the Southern U.S. are basically the same eco-zones. Why doesn't this article even mention millions moving northward from both countries into Canada? America produces more corn than Mexico and is just as susceptible to climate change if food production is the motivating factor. I have lived here in Mexico about 4 years, moved south out of the U.S. Long enough to become more and more aware of American pretentiousness. The only reason America is so rich is that it continues to have the most unsustainable life style in the history of the planet... and that will change, with or without climate change. It is UNSUSTAINABLE.
Reply | Report Abuse | Link to thisway2ec - During past periods of global warming, such as the Eocene Epoch (~56-34Mya), palm trees and other tropical flora grew as fart North as Alaska, so Canada just might be the place we'll want to be, if there's any pretentious Americans left after protecting our Southern border from the > 100M Mexicans.
Reply | Report Abuse | Link to thisOf course if ocean levels rise, most everyone now living on the East coast will be moving in with the relatives in the Midwest, so there won't be much farmland left, either. Not to mention potable water.
On the other hand, if the Yellowstone supervolcano erupts I'll bet that most of the remaining pretentious Americans (>250M? now living here?) will be heading South through if not into Mexico. We probably won't be staying in resort hotels, either.
While global warming is the safest bet for the near term, there's already far too many people on this planet to be fed by its diminishing resources, much less those diminished by any significant disruptive event.
If the entire world's population cannot agree on some humane method of reduction, billions of people will suffer and die, eventually if not much sooner.
Of course any significant short term population decrease would require immediate pubic debate among the entire world population, without somehow igniting WWIII. That debate would be a bit more contentious than some little plan to administer carbon credits, and I haven't heard its beginnings, yet. Of course, private plans may already be in place...
I find in reading those sites that say that climate problems are a myth that their evidence is very sparse and inconclusive. Recently I read Book 1 of the free e-book series "In Search of Utopia" (http://andgulliverreturns.info), it blasts their lack of evidence relative to several myths. The book, actually the last half of the book, takes on the skeptics in global warming, overpopulation, lack of fresh water, lack of food, and other areas where people deny the evidence. I strongly suggest that anyone wanting to see the whole picture read the book, at least the last half. There is also up to date information at:http://www.newscientist.com/article/dn11462-climate-change-a-guide-for-the-perplexed.html
Reply | Report Abuse | Link to this. Recently I read Book 1 of the free e-book series "In Search of Utopia" (http://andgulliverreturns.info), it blasts their lack of evidence relative to their calling overpopulation a myth. The book, actually the last half of the book, takes on the skeptics in global warming, overpopulation, lack of fresh water, lack of food, and other areas where people deny the evidence. I strongly suggest that anyone wanting to see the whole picture read the book, at least the last half.
Reply | Report Abuse | Link to thisThe outdated fertility replacement rate of 2.1 is also clarified.
Genocide should _never_ be the preferred option. Or, indeed, _any_ option seriously considered.
Reply | Report Abuse | Link to thisAnd there are available alternatives, anyway. Sure, they might require us to rethink some of our consumer and lifestyle choices, but that's still preferable to mass sterilization.
"But the study relies on census data to estimate actual emigration, and it assumes that climate change's impact on maize production—for example, via drought—caused migration in the past and will cause it again in future."
Reply | Report Abuse | Link to this*******************
Those unwilling to know and understand history are bound to repeat it, especially as some continue the support of the fossil fuel industry's mis-information and dis-information campaign.
Genocide should _never_ be the preferred option. Or, indeed, _any_ option seriously considered.
Reply | Report Abuse | Link to thisAgreed. There's no justification for genocide. And to people who live like cockroaches, whose only purpose is to eat, breed and die, well, you're right, mass sterilization would be unthinkable.
...which is why the solution will have to come from a private entity, and not some democratic comittee.
It is the natural way, for a species to breed like mad until its death rate ramps up, wipes out great swaths of the population, and leaves the "fittest", and the species is the better for it.
So which is more humane? Quietly preventing ourselves from both breeding ourselves to death, and wiping out thousands of other life forms in the process? Or just letting it happen and let people claw each others eyes out over diminishing resources?
Watch this video that addresses the U.S.' current excessive LEGAL immigration policies and what it stands to do to the country. (It does not address illegal immigration.) You may need to watch it twice to ensure you absorb everything after the initial shock:
Reply | Report Abuse | Link to thishttp://video.google.com/videoplay?docid=4094926727128068265&q=number
sparcboy - Sorry, I couldn't read Roy Beck's magic chart in the video, but to produce its total population curve shown, either then number of legal immigrants annually allowed to enter the country must be significantly increased above 1M or the immigrant's reproductive rate must exceed their death rate by a significant margin over that of the 'currently established' population. Either or both is quite possible, but neither are mentioned.
Reply | Report Abuse | Link to thisEssentially what is shown in this video is a smooth talking salesman presenting a very impressive but inadequately explained chart to a gullible, gawking audience. Looks like paid programming on TV.
If Mr. Beck had simply stated that he was presuming that the U.S. continue increasing the number of legal immigrants allowed annually or that the Catholic immigrants would produce more offspring than the 'currently established' population I would not have had to dismiss the illustrated 'data' presented (always distrust a projection that is represented by a straight line - the forecasting tool is usually a ruler).
The analysis in the Appendix showed negative emmigration "Ratio of Emigrants" in table S2 (2000-05) for a few states: Baja California Sur, Queretero, Quintana Roo, and Yucatan. caused by "some inconsistencies among censuses". This may be true, but an alternative explanation is that that there was net immigration from the USA into these states.
Reply | Report Abuse | Link to thisOur research (1) indicates that the net flow of immigrants from Mexico into the USA is about half of the gross flow. For example, in 2006-07, about 1,026,000 Mexicans entered the USA and roughly 479,000 returned to Mexico. For 2007-08 the figures were 814,000 and 440,000. For 2008-09 they were 636,000 and 433,000. The four states in question all grew significantly (economically and demographically) between 2000 and 2005. I suspect they actually could have experienced net immigration from the USA during those years.
(1) Geo-Mexico: the geography and dynamics of modern Mexico
by Richard Rhoda and Tony Burton (Canada: Sombrero Books, 2010). ISBN: 978 0 9735191 3 6 xiv + 274 pages; more than 100 maps and diagrams. Soft cover. Size (inches): 9.7 x 7.4 x 0.6. http://geo-mexico.com.
Robotics may very well catch up and be cheaper than human labor leaving no jobs for those who may come,then again economic development in Mexico may have its people staying home.
Reply | Report Abuse | Link to thishotblack and scientific earthling: Ya'll are scary.
Reply | Report Abuse | Link to thisjtdwyer: Couldn't have said it better myself. I love a rousing "pubic debate" when population decrease is at stake.
rhodarick: Thanks for facts with good references. Interesting dynamic that I wasn't aware of.
While this article indicates the best educated prediction based on past behavoir, I doubt that it predicts behavoir that will actually occur. As jtdwyer points out, the type, number and severity of natual disasters having nothing to do with climate change could, and probably will, render this report redundant before the world ends in 2012, and certainly before the 70 year timeline indicated.
Assuming the Mayans are wrong though, I doubt any of us question the inability of this rock to support the population that already exists, much less that which will exist if population corrections do not occur. And they will occur, whether we actively get genocidal or lack of resources edits the volume.
Immigrants, legal and illegal, will always come to America with dreams and hope for a better life regardless of our laws, enforcement, or personal agendas. That is how we all got here; our ancestors moved to this land for just that reason.
Anecdotally, when I was farming the only people I could find to do the work were Mexicans and Central Americans. Except for those few with personal issues endemic to every society, I found them to be of the highest character and welcome in my home.
Productivity and economic viability would be decreasing due to declining Anglo birth rate (1.6 children per family in 2006 and declining) where it not supported and increased by the immigrant population (Latino birth rate 2.7). A birth rate of 2.1 is considered necessary to maintain a stable population. Point being: the lifestyle we non-Latino Americans have grown accustomed to would cease to exist without immigrants.
Lastly, while we can get all bombastic about this stuff, we won't have to live in the world we are making, our children will, as will their children. This is not about us anymore.
Over-population definitely needs to be addressed, and it can be in ways that aren't exactly pounded into unwilling heads. In Colombia the rate of population growth was cut back by the quiet opening of affordable sterility clinics to which women who were tired of bearing endless children could go. This worked despite the strong influence of Catholicism. In Kenya, the population growth rate was also cut back, by a combination of well-conceived public campaigns, lowered prices and the desire of women - often unexpressed, as was the case in Colombia - not to bear so many children. Many people in this country were very conscious back in the 60's of the need to cut the number of births and conscientious in doing so. However, the enthusiasm waned. After all, more births means more consumers and a continued rise in the "health" of our economy. Until we come to our senses and take some action that is not just symbolic, agronomists could look for other food crops that tolerate the heat and its concomitant problems. Much of our current food, such as corn, comes from some skillful breeding and selection done long ago. There are many plants with parts which nobody has tried to put into production but which are nutritious, tasty and do OK in the heat. While making these available and modifying what's put on the dining table can only be a stop-gap measure, it could be an aid to those who find they can't grow the old standards any more. The quest for new food items is popular anyway, and foraging has become a gourmet hobby.
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