Brutal Droughts, Worsened By Global Warming, Threaten Food Production Around The World

Severe drought (or Dust-Bowlification) “is the most pressing problem caused by climate change.” As I wrote in the journal Nature last year,  “Feeding some 9 billion people by mid-century in the face of a rapidly worsening climate may well be the greatest challenge the human race has ever faced.”

A vulture picks at a dead steer. Ranchers say many cattle have died because of the drought that has ravaged much of Mexico.

A vulture picks at a dead steer. Ranchers say many cattle have died because of the drought that has ravaged much of Mexico. NPR.

As far back as 1990, NASA scientists projected that severe to extreme drought in the United States, then occurring every 20 years or so, could become an every-other-year phenomenon by mid-century if temperatures kept rising.  They did.

In fact, a major 2011 NOAA report concluded, human-caused climate change is already a major factor in more frequent Mediterranean droughts.

A comprehensive 2011 study of drought, by Aiguo Dai of the National Center for Atmospheric Research, looked at “Characteristics and trends in various forms of the Palmer Drought Severity Index during 1900–2008.” The PDSI is “the most prominent index of meteorological drought” used in the U.S.  That study concluded:

All the four forms of the PDSI show widespread drying over Africa, East andSouth Asia, and other areas from 1950 to 2008, and most of this drying is due to recent warming. The global percentage of dry areas has increased by about 1.74% (of global land area) per decade from 1950 to 2008….

Thus, I believe that our main conclusion is robust that recent warming has caused widespread drying over land. And model predictions suggest that this drying is likely to become more severe in the coming decades.

A look at the headlines and ledes from just the last month make clear that drought is slamming the world right now:

And last week I reposted this story, “Syria: Climate Change, Drought and Social Unrest.”

While the Texas drought has gotten much of the attention in this country, what has happened in Mexico is equally devastating. Since Mexico is projected to suffer even worse warming-driven Dust-Bowlification in the coming decades — and that will certainly have consequences for the United States — it’s worth looking in a little more depth at what’s happening to our neighbor to the south:

The severe drought affecting 22 of Mexico’s 32 states has caused a 40 percent drop in agricultural production, opening the way for food shortages over the next few months, the National Peasants Confederation, or CNC, said….

The drought has ravaged Indian communities, destroying crops and forcing thousands of peasants to leave their ancestral lands and head to the cities.

“As of last November, corn production was at barely 42 percent of the volume projected for 2011, and bean production was only 41 percent,” CNC president Gerardo Sanchez said.

Corn and beans are staples in the Mexican diet and shortages could lead to speculation, sending the prices of these commodities soaring, the CNC said.

“Of the 4.2 million people who fell into food poverty from 2008 to 2010, nearly 75 percent (about 3 million)” live in rural areas, the CNC said.

That was the Latin American Herald Tribune. Here’s the AP from December:

North Mexico Drought Worst On Record

DURANGO, Mexico (AP) — The sun-baked northern states of Mexico are suffering under the worst drought since the government began recording rainfall 70 years ago. Crops of corn, beans and oats are withering in the fields. About 1.7 million cattle have died of starvation and thirst….

Mexican farmers have lost 2.2 million acres (900,000 hectares) of crops to dry conditions and 1.7 million farm animals have died this year from lack of water or forage, according to the nation’s Agriculture Department.

You can listen to the NPR story, “Drought Ravages Farms Across Wide Swath Of Mexico.” That story writes about “the central Mexican state of Zacatecas”:

This is an arid part of Mexico, but normally there’s a rainy season between June and September, allowing farmers to grow crops during the summer. They also tend cattle on the scrubby rolling hills dotted with cactuses.

Rodarte has lived here all his life and says this is the worst drought he’s ever seen.

“Now most people are leaving,” he says, “to the cities, the coasts where it rains, or to the United States. That’s where the people are going to work. And those who are abroad in the U.S. are the ones who are sustaining the families here. They send us a little bit of money.”

That is the classic “adaptation” strategy to prolong drought. As I wrote in the journal Nature:

Human adaptation to prolonged, extreme drought is difficult or impossible. Historically, the primary adaptation to dust-bowlification has been abandonment; the very word ‘desert’ comes from the Latin desertum for ‘an abandoned place’. During the relatively short-lived US Dust-Bowl era, hundreds of thousands of families fled the region.

So yes we should care about drought in Mexico and around the world — especially since these kind of droughts will  almost certainly get worse and more frequent in the coming decades if we keep taking no action.

What does the future look like?  Dai laid it out in a 2010 NCAR study, “Drought under global warming: a review,” the best review and analysis on the subject I’ve seen — see the figure below (click to enlarge, “a reading of -4 or below is considered extreme drought”):

drought map 2 2030-2039

The figure [click to enlarge] charts the PDSI where “a reading of -4 or below is considered extreme drought.”  The PDSI in the Great Plains during the Dust Bowl spiked very briefly to -6, but otherwise rarely exceeded -3 for the decade (see here).

And it keeps getting worse — assuming we are so unpragmatic that we don’t start cutting emissions ASAP [click to enlarge]:

drought map 3 2060-2069

If we allow this to come to pass it would mean large parts of the currently habited and arable land of the planet would be all but uninhabitable and virtually impossible to farm. Dai explains:

The large-scale pattern shown in Figure 11 [of which the figures above are part] appears to be a robust response to increased GHGs. This is very alarming because if the drying is anything resembling Figure 11a very large population will be severely affected in the coming decades over the whole United States, southern Europe, Southeast Asia, Brazil, Chile, Australia, and most of Africa.

The study notes “By the end of the century, many populated areas, including parts of the United States, could face readings in the range of -8 to -10, and much of the Mediterranean could fall to -15 to -20. Such readings would be almost unprecedented.”

For the record, the NCAR study merely models the IPCC’s “moderate” A1B scenario — atmospheric concentrations of CO2 around 520 ppm in 2050 and 700 in 2100.  We’re currently on the A1FI pathway, which would takes us to 1000 ppm by century’s end, but I’m sure with an aggressive program of energy R&D we could keep that to, say 900 ppm.

It’s worth noting that the scientific literature says this could last a long, long time (see NOAA: Climate change “largely irreversible for 1000 years,” with permanent Dust Bowls in Southwest and around the globe).

The time to act is now.

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28 Responses to Brutal Droughts, Worsened By Global Warming, Threaten Food Production Around The World

  1. Rabid Doomsayer says:

    We could not feed nine billion now, let alone mid century. I see a little disconnect here, you show how food production is already a problem and then say it will be a problem mid century. True it will be much worse.

    If we cut down the waste, and shared more evenly we would all be much better off now. Yes I would be better off if I ate less, a forty inch waistline is not healthy. But those savings would not feed another 2 billion.

    Then add into that mix the oil shortages that are inevitable, and the phosphate shortage that is looking to be a problem even sooner. Industrial agriculture is very energy intensive.

  2. Tom King says:

    A vegetarian diet would significantly reduce agricultural land requirements and isn’t unthinkable if meat prices get high enough or moral considerations come into focus.

  3. M Tucker says:

    Of course the time to act is now. Actually the time to act was a decade ago but, just like then, we are doing nothing. We have no plan to do anything. The US is determined to fight any attempt at government intervention and the UN is gridlocked. We are frozen in place while disaster rockets directly at us.

    But may international negotiators and policymakers say that they will limit warming to 2 degrees. They make this sound as if 2 degrees will ensure a safe limit for civilization to continue as we now know it. They make it sound like they have some actual control over this calamity. They DO NOT say what level of CO2 they will allow. They DO NOT say what binding policy they will adopt. They DO NOT say when this emergency brake at 2 degrees will have to take place. The truth of the matter is NO ONE IS DOING ANYTHING and they have no control whatsoever on the level of disaster we will all endure.

    Joe, your post is the shape of things to come.

  4. WyrdWays says:

    Those maps from the 2010 NCAR study do not look clever for the Amazon. And given it’s holding onto several years worth of carbon emissions (60Gt C?), seeing it go up in flames would literally ‘tip’ us from the frying pan into the fire..

  5. SecularAnimist says:

    Joe wrote: “You can listen to the NPR story, ‘Drought Ravages Farms Across Wide Swath Of Mexico’.”

    As it happens, I did listen to that NPR story when it aired on Morning Edition.

    It did not even ONCE mention, or even hint at, any relationship between the Mexican drought and global warming.

    Does the new NPR “ethics handbook” say anything about refusing to cover stories that might be objectionable to its corporate underwriters — who include the American Petroleum Institute’s “Vote 4 Energy” propaganda campaign?

  6. Joe Romm says:

    Yes, lame. Some of those stories do mention warming, and that is something!

  7. Rabid Doomsayer says:

    I am likely to become a finacial vegitarian before I become one due to philosphy. That said, modern meat production is so very cruel in some cases.

  8. nyc-tornado-10 says:

    NPR has another infamous corporate undewriter, david koch. Does NPR stand for “national petroleum radio”?

  9. Lou Grinzo says:

    Once again, I come back to the whole chain of causality in climate change.

    Start with a box on the left that says “emit lots of CO2 for centuries”, and then start drawing arrows from it to new boxes like “global warming”, “albedo flip”, “deforestation”, “hydrological changes”, “sea level rise”, etc. These boxes have arrows connecting them to each other; it’s a complex web of interlocking relationships including knock-on effects and feedbacks. But in terms of human concerns, at the right side of our little chart is the “less food and potable water” box, which leads to things like starvation, climate refugees, and failed states.

    Drought is one of the most serious and most visible boxes in our diagram, and, as Joe and so many others have pointed out repeatedly, we’re not doing nearly enough to address it or those things upstream of it.

  10. Hoedad says:

    Of food and the big ‘dry’ (present and future scarcity):
    “We have enough for everyones need but not enough for everyones greed “Gandi

  11. Peter says:

    The future for humankind is now set for many disruptions even if C02 levels remain as they are today. But if they continue rising at the rate they are now for the next several decades this century could prove to be the most hellish since humans began settling in villages and domesticating animals and starting agriculture 10,000 years ago.

    As a species we have created so much, but we also now have the ability to destroy what we have built over the last 10 millennium in the blink of a geological moment.

  12. Will Fox says:

    In vitro meat, vertical farms, GM crops, aquaculture, portable nanotech water filters, synthetic genomics, algae biofuels grown at sea… there are various technological innovations that could solve the food crisis. Not saying it will be easy, of course – but there ARE some innovations that could greatly lessen the impact of droughts. Technological development is exponential by the way. Read “The Singularity is Near” by Ray Kurzweil. Also “Abundance” by Peter Diamandis.

  13. Raul M. says:

    Yes, pragmatism and the natural world for better or worse.

  14. Joan Savage says:

    Great image. I’d like to see (and be in) a group brainstorm on such a diagram. My first add-in would be to have the starting box represent centuries of releasing fossil fuel combustion products, as we have consequences not only from accumulation of CO2 but also sulfur dioxide, soot, etc. that interact with the CO2 accumulation. We even have population expansion that depends on fuel-driven trade and mass agriculture.
    I see two big branches from CO2 to heat and acidity.

  15. Mike Roddy says:

    The memo went out a few years ago, broadcast by Andy Revkin: “Do not ever connect a weather event to global warming!”. Reporters, frightened for their jobs, bit.

  16. Lewis Cleverdon says:

    The threat described by Dai seems to me to be seriously understated above, for several reasons.

    First, as Joe notes, Dai used the moderate IPCC A1B emissions scenario for the projections of the northward retreat of greater rainfall. This is not only incorrect because we are on the far steeper A1F1 emissions growth pathway, it also ignores both the entirely predictable decline of the planet’s natural carbon sinks and the rising CO2e outputs of six out of seven of the interactive mega-feedbacks that are already active.

    In terms of the feedbacks’ scale, just the Amazon forest is reported to hold over 100GtC, let alone the fraction of the rest of the world’s forests that would have burnt by 2070 under the ‘A1B’ desertification scenario. Moreover, the massive increase of rainfall at high northern latitudes would both greatly accelerate the melting of permafrost and maximise water saturation of the tundra and thus the fraction of its carbon emitted as methane. It would also greatly increase warmed water runoff into the Arctic Ocean, thus accelerating both albedo loss and clathrate destabilization.

    Second, under the deficient strategy of relying on cutting GHG outputs to resolve AGW, we are now fully committed to the migration of rainfall shown by 2070, since we have ~40 years of warming already in the pipeline (2052) followed by the timelagged warming from our emissions during the next 20 years (2072) plus the sum of the various interactive feedback emissions in that period.

    The inference seems pretty clear that ending our global emissions by agreeing a global climate treaty ASAP is entirely necessary but it is patently insufficient to avoid both terminal impacts on our civilization and the uncontrollable escalation of the feedbacks thereafter.

    In short, if we fail to deploy effective Carbon Recovery and Albedo Restoration techniques ASAP in addition to ending anthro-GHG outputs, we fail to avoid calamity.

    Given that much of the dissent in America seems increasingly impressed by the delusion that encouraging commercial deployment of non-fossil energy could resolve the AGW problem
    – regardless of the reality that, in the absence of a climate treaty, any fuels displaced by renewables or energy efficiency projects are being bought and burnt elsewhere –
    it is hard to see much prospect at present of the popular pressure needed to cause the US govt to review its policy of a ‘brinkmanship of inaction’ and to start facilitating the requisite global treaty. The veil of ‘plausible incompetence’ obscuring that Bush-era policy has endured surprisingly well.

    With respect, I suggest that Dai’s work confirms that a strategic review is urgently required among dissenters.



  17. John Tucker says:

    Drought and related problems are decimating the entire gulf coast oyster harvests.

    Farming, forestry, fishing; climate change and the petroleum industry are destroying ways of life in the south and southwest that had become American tradition for over a hundred years. [if not considering indigenous populations, thousands of years]

    Drought Suspected in Florida Bay Oyster Die Off ( )

  18. John Tucker says:

    Here are some supporting links for a gulf coast fisheries catastrophe :

    Experts explain oyster die-off; oystermen call for closures – mar 7 (|topnews|text|FRONTPAGE )

    Disasters doom Texas oyster crop – Updated 12/14/2011 ( )

    Drought is damaging Texas’ oyster fisheries – 7/31/2011 ( )

  19. M Tucker says:

    The video paints a very clear picture of the immense threat and should be included in all secondary school curricula on global warming. It is a shame that protecting the home planet is no longer part of NASA’s mission.

    “We owe it to our children and grandchildren.”

    You would think this should motivate all parents to pressure congress and the President to do something. But, even a well educated man like President Obama, who is definitely concerned about the future of our planet given his efforts to stop nuclear proliferation, seems to be more concerned about name calling than the dire threat of global warming when it comes to the future of his children.

  20. M Tucker says:

    Sorry. Posted in the wrong spot…doing too many things at once.

  21. John Tucker says:

    I include ranching with farming here in fla but really thats its own legacy out west. Perry and Inhofe have about killed that without looking back.

  22. Gingerbaker says:

    “A vegetarian diet would significantly reduce agricultural land requirements…”

    Not so sure about that anymore – read:

  23. Joe Romm says:

    Not an impressive link.

  24. Dick Smith says:

    Maybe it’s just me, but I’ve been looking at your many PDSI map posts, and have concluded the color scheme is very difficult to follow.

    I have tried (and failed) to create a strong mental picture of the areas that would be at -4 of below.

    REQUEST: In addition to the overall PDSI map, is it possible for you or someone else to put together at least one map of just those countries at -4 or worse. I would really like to grasp this “severe” drought area clearly–and see how it changes over the years.

    Any way to do this easily?

    A complete series of maps (say, from -1 to -8 or more) would be better, but probably not necessary.

  25. Joe Romm says:

    They come from NCAR. But just click on them to enlarge. The main point is that it’s a disaster over large, large areas.

  26. Mark says:

    I find this extremely depressing. It’s beyond words.

    Thanks to those who are continuing to fight.

  27. TomK says:

    I guess everyone needs to make sure their family members are in good standing with society so that eventually they can become one of the 144,000 that will be on the spaceships that will depart for the new planet come 2075…

  28. Jim Eberle says:

    Great post Lewis. You have obviously studied Jevon’s Paradox when you state that in an aggressive effort to replace hydrocarbon fuels with alternatives, that the trajectory of hydrocarbon fuel consumption will remain unchanged due to those fuels being used for other purposes. This is so insidious and makes the issue od climate change just that much more urgent.