Overpopulation Is Not the Problem…If Climate and Biodiversity Do Not Count

In his recent New York Times article, “Overpopulation is not the problem,” geographer Erle Ellis comes to two optimistic conclusions: (1) we can feed our planet’s growing human population, and (2) we can do that without further destroying nature. Ellis’s optimism is to be commended. Ultimately, we are not going to fix the environmental problems we face without an endgame plan, and an effective endgame plan simply cannot be devised or implemented without optimism. But Ellis’s message seems dated in his criticism and pollyannish in its narrow focus. It also seems out of place; after I wrote the paragraphs below, I went to the web to see what else Ellis had published. What I found was that he is a widely published academic author, and that his publications (that is, the ones that I downloaded and found time to read) seemed well articulated and substantive, challenging yet balanced, insightful and thought-provoking. What I did not find was the dismissive and derogatory tone that Ellis takes in his New York Times op-ed. Maybe he was edited in a way he would not want to have been edited? He has since noted that he did not choose or appreciate the title of the piece, which was chosen by the New York Times editors. To give him the benefit of the doubt, perhaps the editors left out the subtleties and inserted the jabs. It all made me second-guess my own dismissive and derogatory tone in the subsequent paragraphs below, but I decided to let stand the cathartic narrative I composed directly in response to the bombastic narrative that Ellis allowed to be published under his name. Ellis begins by ridiculing the notion that humans are like bacteria in petri dishes with a strictly limited carrying capacity. He bemoans that “[e]ven today, I hear some of my scientific colleagues repeat these and similar claims” about an inherent “natural” carrying capacity for people. Really? No doubt, in some cases in the past, some biologists (and some guys who weren't biologists, but really wanted to play a biologist on TV) have been too willing to think about Homo sapiens solely in terms of textbook biological principles—principles that do not translate into practical tools for understanding how human societies work. Yet today, such dramatic and simplistic claims emanating out of the biological sciences are as rare and dated as dinosaurs. Yes, Ellis’s basic arguments about humans and carrying capacity have merit, and these arguments ought to be explained to every sophomore…in high school. But I would really like to know with which scientists Ellis is conversing; how many of them are not fully aware that, as he states:

The conditions that sustain humanity are not natural and never have been. Since prehistory, human populations have used technologies and engineered ecosystems to sustain populations well beyond the capabilities of unaltered “natural” ecosystems.

That might be nicely stated (though one blog I read took issue with “Since prehistory”), but it hardly constitutes news to any scientist I know. Or most high school sophomores, for that matter. Ellis is not so much beating a strawman as he is sweeping together a pile of hay from a neglected stable and jumping on it. But let’s assume Ellis’s main point is that we should not be pessimistic today about the human ability to continue expanding the Earth’s carrying capacity. Ellis is drawing a line-in-the-sand challenge to the environmental community in stating that: “There is no need to use any more land to sustain humanity—increasing land productivity using existing technologies can boost global supplies and even leave more land for nature—a goal that is both more popular and more possible than ever.” As I read it, this is Ellis's key point, and it deserves careful consideration. No doubt, there certainly is concern within the environmental community over this proposition, and Ellis's optimism will certainly generate much debate, and I am looking forward to seeing the debate play out. As to how it will end, my guess—I’d like to say “educated guess,” but it may be my own pollyannish guess—is that although productivity will not be as easy as his wording implies, Ellis's faith in human ingenuity is well placed. I pray I’m right in agreeing with him, although almost inevitably the ultimate answer will be one of degree rather than a binary correct/incorrect determination. Yet something is missing here. While the debate over land productivity is critical, it is only a very small piece of what is at stake—and what is most unfortunate about Ellis’s argument is that he comes to his conclusions with blinders on. His analysis targets land, specifically the productivity of human land use and how land use translates into human sustenance. No doubt, from an environmental studies perspective this is a critical starting point, for any policy-relevant global, regional, or local environmental analysis requires that we look at human land use patterns. Yet the size of the planet’s human population is not all about land use. Hardly. Most obviously, there is a strong connection between population levels and climate change. That connection is not hard-wired; for example, with my flights to three professional conferences this year (all of which I feasibly could have instead attended virtually), I can guarantee that my carbon footprint dwarfs the average person’s carbon footprint. Which is to say that a few guys named Charlie from Cambridge, Massachusetts, can spew out a lot more carbon pollution than a Mexico City’s worth of Carlos’s (no, I have not crunched the numbers on this—too embarrassing). But as our energy systems are set up today and for the foreseeable future, it’s more than a safe bet to equate more people with more carbon in the atmosphere, and all of the resultant deleterious effects that a disrupted climate could bring (I'll spare you the list of global bummers). Indeed, not only does the very act of intensifying agriculture—e.g., making and applying more fertilizer—enhance greenhouse gas emissions through enhanced energy consumption, but it uses more water. Moreover, the enhanced release of nitrogen and phosphorous cause eutrophication of land and water, thereby decreasing biodiversity, disrupting productivity of estuaries, generating dead zones in our coastal seas, amongst others. And biodiversity? It would be wonderful to see human technology safeguard and restore biodiversity habitat. No, scratch that—it is wonderful to see this causal phenomenon, for Ellis is correct in emphasizing that human agricultural ingenuity has resulted in less acreage of lost habitat, at least in comparison to the acreage that would have been necessary to create an equivalent amount of food without, e.g., fertilizers, pesticides, and high-yielding varieties. But what about the very effects of those human innovations on biodiversity? This of course harkens back to the Silent Spring origins of “modern” environmentalism, and while we can argue about how drastic or benign these effects will be, these are real-world effects that have been and can be exacerbated. This is something we have to be extremely careful with in regard to the use of GMOs, which may – or, it is important to give equal emphasis, may not – affect biodiversity directly. Then there are the effects of climate change on biodiversity. I spent much of the past two years co-editing an Island Press volume entitled Climate and Conservation: Landscape and Seascape Science, Planning and Action, and the pessimistic reader might be tempted to assume that the experience could have only made me despondent and hopeless. It did not—quite the opposite, overall. By thinking big (my biologist friends get upset if I don’t add in the tired phrase here: “across extensive spatial and temporal scales”), there are many ways we can help biodiversity adjust to a changing climate. And yet climate change does (as in, does now) affect biodiversity, and the prospects under continued change are challenging and intimidating at best. Ellis never said this wasn’t the case. But by publishing an editorial in the second most widely circulated newspaper in the United States that implies that overpopulation is not an environmental problem because it is feasible that we could feed 9 billion people down the road, one is only left to wonder why he focused so single-mindedly on the human sustenance factor in the overall environmental equation. It will indeed be a marvel of human nature if we can feed 9 billion people, and as a species, Homo sapiens has over and over proven just how marvelous it can be. Maybe it’s just too bad that many other kinds of marvelous nature won’t be left for those 9 billion people to see and understand.