The Volokh Conspiracy

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How Great Was the Green Revolution?

Advanced crop varieties may have given the world an extra year's worth of GDP


How important was the "Green Revolution" to feeding people in developing countries and improving living conditions? A new paper in the Journal of Political Economy suggests it was quite substantial. The abstract for the paper, "Two Blades of Grass: The Impact of the Green Revolution," by Douglas Gollin, Casper Worm Hansen, & Asger Wingende is as follows:

We estimate the impact of the Green Revolution in the developing world by exploiting exogenous heterogeneity in the timing and extent of the benefits derived from high yielding crop varieties (HYVs). We find that HYVs increased yields by 44 percent between 1965 and 2010 with further gains coming through reallocation of inputs. Higher yields increased income and reduced population growth. A ten-year delay of the Green Revolution would in 2010 have cost 17 percent of GDP/capita and added 223 million people to the developing world population. The cumulative GDP loss would have been US$83 trillion, corresponding to one year of current global GDP.

This is a lengthy and fascinating paper, high-lighting the importance of innovation (and agricultural biotechnology in particular) to improving human well-being.

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  1. All real remedies have come from technology, the seatbelt, not torts has saved lives. The lawyer profession has always obstructed technology.

    1. Your ex-wife's lawyer must have screwed you but royally!

  2. I think of the green revolution as buying us time to stop population growth. An exponentially growing population will run out of food eventually.

    1. Better fed people have fewer babies.

      1. Westernization -- higher income and standard of living, urbanization, jobs for women -- leads to a decline in birth rate. Is there evidence that higher crop yield alone does?

    2. Nah, it will simply grow an exponentially larger food supply, by use of exponentially more energy, in an exponentially expanding universe, featuring an unlimited supply of exponents.

    3. Yes, but how about an imploding population? Basically every developed country on Earth is at well below replacement, levels you'd never normally see outside of a war zone or the middle of a serious plague.

      This is slightly concealed by heavy immigration from 3rd world countries, but the 3rd world is, thankfully, rising out of poverty.

      What happens when EVERY country has imploding populations at the same time?

      1. We adjust to a world that only has, say, 5 billion people? So we can still have steaks once and a while, or go hiking someplace nice without winning a lottery for a hiking permit? Maybe enjoy the luxury of a single family home?

        You can't have exponential growth forever. The only choices are to maintain a stable population at some level, or do boom-n-bust population cycles that are pretty unpleasant during the periodic 'bust' cycles.

        1. "So we can still have steaks once and a while"

          Lamb chops, pork chops, chicken, seafood, and sausage can substitute in a pinch.

          1. Not in a world of 20 billion people. That's Soylent all the way :-(.

        2. Only 5, then only 4, then only 3, then...

          Explain to me why it stops imploding.

      2. "What happens when EVERY country has imploding populations at the same time?"
        The fairy tales of the social safety net for the old, economic growth every year, my children will live better than myself, etc. will vanish

    4. The population is not exponentially growing. We've known for decades (almost coming up on a century) that human population growth declines as a function of prosperity. The entire premise of Malthusian "population bombs" has been conclusively discredited.

      1. I would be perfectly happy if in the year 2100 world population stabilized at around 2 billion.

        1. What stabilizes it?

        2. I guess you think that is what nuclear weapons are for.

      2. Not quite. You are correct that the growth rate seems to decline with prosperity.

        But, a population that grows at 1% (vs 3%) is still growing exponentially.

        1. While true that a 1% growth rate is still exponential, the actual evidence shows that the growth rate decline does not stop there. It can (and frequently does) go to zero and even below.

    5. The best birth control is a 6th grade education for females.

      1. so why did you stop at grade 5?

    6. Agrarian cultures breed farm labor -- lots of children ensure that their parents will be fed in old age.

      I'd want to see some data, but the claim is that higher yields reduced the need of more children. It definitely reduced the amount of labor needed.

  3. Higher yields increased income and reduced population growth.

    The population growth part of that assertion is a startling reversal of a centuries-old historical principle that increased food availability has led over time to increased populations. Presumably there will be interesting explanations for the new reality. Maybe something like, more prosperous people have fewer children.

    If so, I hope something notable gets mentioned to deal with the particulars. More people having fewer children can still deliver population growth, if in the aggregate they reproduce more efficiently than fewer people having more children. A lot depends on the relative values of, "more," and "fewer." And of course, availability of more food may tend to prolong survival, which would be no small thing for population predictions.

      1. They are not falling in Sub-Saharan Afric

  4. Who knows what the green revolution could have delivered, if anti-GMO cults hadn't obstructed it? Just golden rice, alone, could have saved to many lives if its use hadn't been so widely blocked.

  5. I knew Dr Borlaug. A truly great, great man. And the humblest person I've ever known.

    He saved more lives than Hitler, Stalin, Mao and Pol Pot together managed to kill. And nobody has ever heard of him.

    Proof of the old adage: It's amazing what can be accomplished when nobody cares about the credit.

  6. 1. For those cheering low birthrates... natural selection favors subgroups of humans that have higher birthrates. Higher birthrates will return. Humans can no more repeal the laws of natural selection than they can gravity. The "don't reproduce" crowd will die out, with no heirs. The humans who inherit the earth 400 years from now are the great grandkids of people having 4 and 5 kids now. Look around, who is having 4 and five kids despite high prosperity? They will inherit the earth, and it wont take long ...several generations.

    2. A few generations from now, women will routinely have babies in their late 50s and early 60s, raising the growth rate. We can already do this through IVF, but its expensive.

    3. The Malthusian crowd "people will starve when we run out of resources" are both always right and always wrong. There is a natural carrying capacity for the number of humans, but we have no idea if its 10 billion, 20 billion, 30 billion, or more. Technology will eventually run into the laws of physics, but we are nowhere near close.

    4. Wild animals don't care about their environment. They eat, crap, reproduce, and die until they reach carrying capacity. Humans are wild, and I am skeptical that, long term, environmentalism compatible with #1. We can rationalize and reason, but people who rationalize themselves out of children wont pass on their genes (culture), see #1. Environmentalism postpones the inevitable.

    Humans have the unique ability to change the carrying capacity of their environment. The carrying capacity of humans in orbit used to be zero, now its several and 10 years from now maybe hundreds. Soon we will raise the carrying capacity of the moon to thousands. Did you know Jupiter's moon titan has vast oil reserves? We are going to need them!

    The green revolution will continue, because it has to.

    1. To give to a mathematical example of #1: Suppose there are 2 subgroups of humans, A and B. A is today 10% of the population, but grows at 2%. B is 90% of the population, but grows at 0.7%. In 100 years, A will be about 28% of the population, in 200 years A will then be 68% of the population. After 300 years, we will see a complete reversal and A will be 90% of the population.

      The rate at which A takes over depends on the relative growth rates. If A instead grows at 3% (B remains at 0.7%), A will be majority (>=50% of population) after only 100 years.

      Natural selection is unavoidable, and cold. The great grandkids will inherit the Earth.

    2. Re your #1 ... you're right. The first 10 minutes of 'Idiocracy' is hilarious, and true.

      1. Depends on whether "smart people" are smart enough to recognize the inevitability of #1 and pass on their smart genes to a lot of kids and grandkids.

    3. Evolution favoring cultural subgroups?

      That's social Darwinism, Jack. Don't go down that road.

      1. I did not figure you for a science denier. Evolution and natural selection are a facts. The babies of the people who have babies will inherit the earth.

        1. How many babies you have is behavioral.
          Behavior is not genetically determined.

          Social darwinism is bad science.

    4. re: #1 about natural selection - You are assuming that the decision to have babies is a genetically-controlled factor. If it were purely controlled by genetics - or even mostly controlled by genetics - you would be right. The evidence, however, suggests the opposite. Human population growth rates decline as prosperity increases across all nationalities, races, ethnicities, etc.

      The concept of natural selection does not apply to this scenario because the selection is not "natural". That is, it does not follow the definitions used by evolutionary biologists.

      re: #2 - Maybe. You are underestimating the difficulties of raising a youth (and the human power to predict that future pain). As someone who started a family late (early 40s), I can attest to the difficulty. Will a few loons choose to try to raise a teenager while they're in their late seventies? Probably. Enough to be statistically significant? No.

      #3 - Absolutely right.

      #4 - I disagree. Again, we have a unique ability to predict the future and use those predictions to guide behavior both individually and collectively. Of course, our ability to predict the future is deeply flawed and often wrong - but the benefits of environmentalism as a luxury good seem awfully well established.

      But yes, the green revolution will continue - as you say, because it has to.

      1. Clarification - I wrote "the decision to have babies". I should have said "the decision of how many babies to have". Apologies and I'd really like an edit button...

      2. I am not assuming its genetic. It does not matter whether its genetic, environmental, or social - or a combination of factors: Phenotypes ( that reproduce more inherit the earth.

        And yes, I know how much effort is required to raise kids, I have them.

        The "average" population growth rate hides a lot of variation. It's a mistake to look at averages.

        1. Actually, it matters a lot. Environmental issues, for example, are not inheritable. If one of those environmental factors is affluence (and all the evidence suggests that it is), then every demographic will go through the same cycle break the Malthusian growth assumptions. That's the very antithesis of natural selection.

          Social, by the way, is merely a subset of environmental. Furthermore, "social" is contagious - which means that your "social" proclivities are guided far more by your current friends and neighbors than by your grandparents. Again, undercutting the actual definition of "selection" as used by evolutionary biologists.

    5. The classic SF story "The Marching Morons", 70 years old this month, starts with the premise that smart people have better things to do than reproduce and extrapolates that for a few centuries.

      1. You would be hard-pressed to find a better writer or a bigger cynic than C. M. Kornbluth. He died far too early.

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