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Our future, our universe, and other weighty topics


Friday, May 2, 2014

Fallacies of a Resource Depletion Denier

In the Wall Street Journal blog a few days ago there was an essay by Matt Ridley entitled “5 Reasons the World Is Not Running Out of Resources.” Let's look at these reasons, and see whether they give us any basis for not being very worried about the issue of resource depletion.

Reason #1 is “More Productive Land.” Ridley reasons that we have been improving the productivity of land by dumping more and more fertilizers in it, and that this trend will continue, causing more productive farmland. But this ignores the gigantic problem of soil depletion, the fact that as we try to maximize the agricultural productivity of farm land, we are depleting the organic fertility that took nature centuries to build up (through the natural decay of organisms and rocks). According to this expert, some 40% of the world's soil has been classified as degraded, and it has been estimated that we only have 60 years left of good topsoil.

Will we be able to dump more fertilizer to cover the gap? Fertilizer is created largely from natural gas, and it estimated that in sixty years we will be running short of natural gas. In short, rather than having a blessing of “more productive land,” we may have a severe problem of less productive land because of declining soil fertility.

Reason #2 on Ridley's list is “Overestimating Water Demand.” Ridley claims that during the 1960's and 1970's experts overestimated how much water the world would need. So what? Many experts during the past ten years have concluded that we will have a huge problem supplying fresh water for a growing world population, particularly with global warming (which increases droughts). You do not dismiss that concern by mentioning some alleged water overestimation that took place 40 or 50 years ago. Ridley also suggests that maybe we can use solar-driven desalination to get fresh water from sea water, but that is a pie-in-the-sky type of suggestion. Currently less than 1% of desalinated water is produced from solar energy.

Reason #3 on Ridley's list is “The Shale Revolution.” To explain why shale is no easy answer to the problem of oil depletion, let's look at what is called an oil resource pyramid, an example of which is shown in the diagram below.

oil resource pyramid

At the top of the oil resource pyramid is crude oil – oil that is highly concentrated and easy to extract. As we move down the pyramid, towards its base, there are resources that are more abundant but less concentrated, and more difficult to extract. It is more expensive to extract offshore oil that crude oil; and extracting oil from tar sands is even more expensive and difficult; and extracting oil from shale is even more expensive and difficult.

The more we move down this pyramid, the lower is the energy return on energy invested (EROI). At the top of the pyramid, with crude oil, you have an energy return on energy invested of about 30, meaning you can invest one unit of energy and get 30 units of energy back. But as you move down the oil resource pyramid, the energy return on energy invested plunges. Nowadays tar sands only have an energy return on energy invested of about 3.0, meaning you have to invest one unit of energy for every three units you get back.

As we start to run out of crude oil (which may be in only a few decades), we will work our way down the oil resource pyramid, trying to extract resources that are more and more difficult to extract. At some point it will no longer be economical to extract any more oil from the resource pyramid, because the cost of extraction will be too high, and the energy return on energy invested will be too low. For example, there will be no point in investing 100 units of energy to get back only 90 units of energy from shale oil.

Once that happens, it will be just as if we have run out of oil, even though we will not have run out of oil. There will still be enormous amounts of it available in hard-to-extract resources such as shale, but it will no longer be economical to extract it.

The type of resource pyramid I have shown for oil also exists for coal and natural gas. In the case of coal, most of the reserves are lower-quality coal, as the graphic here illustrates.

So while strictly speaking it may be accurate to say that we are not running out of energy resources, it is just as accurate to say that before long our energy resources will be severely depleted. Before long, it may be effectively as if we were running out of energy resources, even though we will still have lots of hard-to-extract reserves left in the ground. This is why reason #3 offered by Ridley (“The Shale Revolution”) is not very convincing.

Ridley's reason #4 is “Alternative Sources.” For some reason, Ridley focuses here on phosphorus, which is one of the minerals we are most worried about depleting. Noting that phosphorus is vital for agriculture, and that phosphorus mines are all but depleted, Ridley suggests this is no problem because there are lower grade deposits available. But this ignores the whole “resource pyramid” issue, that when you extract a resource from the bottom of a pyramid it is much more expensive and time-consuming to get it. Ridley then gives us unintentional comedy: “If we get desperate, all the phosphorus atoms put into the ground over past centuries still exist, especially in the mud of estuaries. It’s just a matter of concentrating them again.” That's hilarious. We have no technology for extracting trace atoms from soil in any economical matter that can be used for agricultural purposes, and there is no reason to think we will have such a technology in the next seventy years. Meanwhile, long before that, we are scheduled to run out of phosphorus. Ridley's comments on phosphorus do absolutely nothing to bolster his thesis, and in fact, serve to remind us of something contrary to his thesis.

Ridley's reason #5 is “Greater Affluence and New Technology.” Ridley says the following:

In many respects, greater affluence and new technology have led to less human impact on the planet, not more. Richer people with new technologies tend not to collect firewood and bushmeat from natural forests; instead, they use electricity and farmed chicken—both of which need much less land.

This reasoning doesn't hold up to scrutiny. Yes, richer people use less firewood, but the electricity they use has an enormous environmental cost, because so much electricity is produced by coal, which is worsening global warming. In addition, there are countless environmental costs associated with supporting the lifestyles of rich people. While there are some cases of technology that decrease the human footprint on the environment, in general greater affluence leads to a greater impact on the environment, not less.

In short, all of Ridley's five reasons are fallacious. Rather than being complacent about resource depletion, we should be very worried. We have a moral duty to conserve the planet's declining resources. The best way to do that is to live a simpler life with a smaller carbon footprint. The more energy and resources each of us uses, the greater the likelihood that our children and grandchildren will suffer from our wasteful resource-depleting profligacy.  When planning a purchase of a car or house or consumer good, don't think about what will impress your Facebook friends -- think about what you need.