July 07, 2007
Humans Use Nearly A Quarter Of World Biomass?

A recent research report published in the Proceedings of National Academy of Sciences USA by a group of German and Austrian researchers find that humans are already using a quarter of the world's biomass.

Human appropriation of net primary production (HANPP), the aggregate impact of land use on biomass available each year in ecosystems, is a prominent measure of the human domination of the biosphere. We present a comprehensive assessment of global HANPP based on vegetation modeling, agricultural and forestry statistics, and geographical information systems data on land use, land cover, and soil degradation that localizes human impact on ecosystems. We found an aggregate global HANPP value of 15.6 Pg C/yr or 23.8% of potential net primary productivity, of which 53% was contributed by harvest, 40% by land-use-induced productivity changes, and 7% by human-induced fires. This is a remarkable impact on the biosphere caused by just one species. We present maps quantifying human-induced changes in trophic energy flows in ecosystems that illustrate spatial patterns in the human domination of ecosystems, thus emphasizing land use as a pervasive factor of global importance. Land use transforms earth's terrestrial surface, resulting in changes in biogeochemical cycles and in the ability of ecosystems to deliver services critical to human well being. The results suggest that large-scale schemes to substitute biomass for fossil fuels should be viewed cautiously because massive additional pressures on ecosystems might result from increased biomass harvest.

One could dispute this result. How one measures biomass usage will affect how high a figure will be assigned to human usage. But consider for example the world's fisheries. We are cutting back on the sizes of the world's fisheries. One could argue that since we are using such a large fraction of all the fish we are effectively using all the algae and other microorganisms in the food chains of those fish which we eat.

If we plant lawns and fruit trees in our yards then are we appropriating that biomass for our use? Seems like it. If we didn't plant those lawns other plants would grow there and other species would make use of those plants in ways that we currently prevent (e.g. we battle to keep out gophers).

This result illustrates why I think biomass energy is a bad idea. We do not have large amounts of land as yet unused. We should avoid development of yet more ways to make land useful. Even without the development of biomass energy I expect both human population growth and human industrialization to increase human land use to an extent that wipes out lots of species. Human continue to greatly shrink the wilds with no end to that shrinkage in sight.

Industrialization will continue to raise the demand for timber. That will shift more lands from their natural state into forest monocultures. Industrialization will continue to increase the size of dwellings and of lawn areas around houses. This will decrease the amount of land available for nature. Rising living standards will increase the buying power of people who like meat. This will cause a shift of more lands toward agriculture to raise grain crops and for grazing.

The human population is about 6.6 billion people and the US Census Bureau projects it might reach 9.4 billion by 2050. If the Chinese government loses the ability to enforce its "One Child" policy then the world's population could go much higher. Also, the development of cures for major diseaes and rejuvenation therapies will drastically cut the death rate in industrialized countries.

Nanotech replications will make solar power and goods production extremely cheap. Therefore hundreds of millions or even billions of humans will gain the ability to use huge amounts of land just for massive mansions.

The full paper (PDF) is available with open access.

Share |      Randall Parker, 2007 July 07 09:17 AM  Trends Habitat Loss

back40 said at July 7, 2007 10:05 AM:

You might find this paper interesting and relevant.

if one accepts that virtually all of nature is now domesticated, the key scientific and social questions concern future options for the type of domesticated nature humans impose upon the world

Some are beginning to grasp the implications of a domesticated world and now realize that latter day attempts to preserve wilderness are less useful than seeking to improve the quality of "working landscapes".

Fat Man said at July 7, 2007 11:07 AM:

So What? It is not like there is somebody else to share it with.

David Mathews said at July 7, 2007 11:53 AM:

Hello Everyone,

This whole argument is pointless.

As the fat man says, "So What? It is not like there is somebody else to share it with."

Humans are the most insane and self-destructively suicidal animal that evolution has ever had the displeasure of creating. Humans don't need to share the Earth with any other creatures because ... well, because our machines will provide everything for us.

Needless to say, Nature will handle the Homo sapiens harshly. Our species will soon lose its both its energy and its food. Without energy and without food our species will find it very difficult to dominate the Earth.

Homo sapiens is a species hellbent upon extinction. For all of our efforts and "success" this is exactly what Nature will gift to us: Extinction.

Nature doesn't have to share anything with humankind. The Earth doesn't need the human plague.

If only our fate was undeserved ...

Synergy6 said at July 7, 2007 1:18 PM:

Meh. The dinosaurs didn't mess with nature, and they took it up the ass. As least we can partehhhh before we become extinct.

David Mathews said at July 7, 2007 2:49 PM:

Hello Synergy,

The dinosaurs survived and prospered for millions of years. Humankind has partied for only 100,000 years. It seems like our party won't last for another century.

The dinosaurs needed a global-scale catastrophe to finally wipe them out for good. Homo sapiens are a global-scale catastrophe.

Humans love the dinosaurs and spend a whole lot of time thinking about them scientifically and within the popular culture. After humans are gone, there ain't going to be any animals obsessing about us or devoting their creative energies to imagining our existence.

Enjoy this moment while it lasts. When it is over it is over forever. Extinction is forever.

Hopefully Anonymous said at July 7, 2007 3:43 PM:

Dave Matthews,
In my opinion (and based on your homepage link) you are spamming the comment section of this blog.

Randall Parker said at July 7, 2007 5:29 PM:


I have deleted many posts of David Matthews. He's one of the few people whose comments I delete. But if you engage him I'm less likely to delete him since then your replies are to non-existent comments.

He really provides no added value except to serve as a reminder that there are people in the world who think like him.

Brian Wang said at July 7, 2007 11:38 PM:

Improving on existing established trends with technical refinement. More domestication and more efficiency will reduce the footprint and up the productivity.

The blue revolution of aquaculture.

Scientific american discusses it

A cow requires around seven kilograms of feed grain for each kilo of meat, while a carp requires around three kilos or less. Fish farming economizes on feed grain, and of course on the land area needed to produce it

I have an article with more stats

In 2004, capture fisheries and aquaculture supplied the world with about 106 million tonnes of food fish, providing the highest apparent per capita supply on record. Of this total, aquaculture accounted for 43 percent.

Aquaculture continues to grow more rapidly than all other animal food-producing sectors, with a global average annual growth rate of 8.8 percent per year since 1970

Adjustments can be made to prevent waste build up problems while still maintaining a smaller ecological footprint.
Bioengineering can be performed to make the processes more energy and resource efficient and productive.

In about a decade, meat factories using stem cells will reduce the resource usage for cows and other farm animals

also, high rises converted to urban aeroponics
Skyfarming, vertical farming

Randall Parker said at July 8, 2007 10:39 AM:

Brian Wang,

1) Mid-ocean fish farming: The middle area of many oceans is nearly lifeless because there's not enough materials in the water to support growth of algae to provide food for fish. Can we find ways to build enclosed floating ponds in the middle of oceans that could get fertilized to grow a complete eco-chain? I'm thinking massive nanostructures perhaps down 30, 40, 50 feet below the surface that would go on for a mile in any direction with walls around the edges. This would be akin to using deserts to grow food on the land.

2) High rise aeroponics: But a square foot on the 20th floor of a skyscraper costs way way more than a square foot of Nebraska farm land. Yes, it could be done. But unless large chunks of the country are declared off-limits for farming (and good luck with getting that law passed) I do not see high rise farming taking off. Maybe some day when nanomaterials makes building upward much cheaper the economics will change in its favor.

Dave Gore said at July 8, 2007 11:09 AM:


Your comment on mid-ocean fish farming reminds me of tech dreams ten years ago to combine aquaculture and oceanic thermal operations in floating cities. One link is at http://oceania.org/ .

Nissl said at July 8, 2007 3:01 PM:

One thought on biomass applications, particularly things like cellulosic ethanol, thermal depolymerization, and gasification (forget the exact term) is that there are vast amounts of agricultural waste generated every year. Biomass technologies that convert this waste into usable energy with even modest efficiency could replace a very large chunk of our oil usage.

Bob Badour said at July 8, 2007 3:20 PM:

To amplify Nissl, the methane from livestock waste is also a major contributor to greenhouse gases.

As energy costs increase, the economic incentive to divert the methane will increase. The efficiency increase from diverting the methane will have a double effect on greenhouse gases.

Brian wang said at July 8, 2007 7:15 PM:

Open ocean aquaculture is progressing now

Most current open ocean aquaculture is within 3 miles of shore

It is still a tiny part of the overall aquaculture business. Might be a few thousand tons per year

A 2006 study of open ocean aquaculture

5400 cubic meter cage

UN fisheries organization aquaculture system review

Ocean drifter concept with a 64,000 cubic meter pilot system in 2003-2004

Work continues on ocean drifter

a new form of aquaculture where huge cages of fish move across the open seas on deep ocean currents. Thatís one solution MIT has posed to the problems created by traditional fish farms. Setting cages adrift means there arenít the same pollution problems - uneaten feed and fish waste canít accumulate.

The beauty of this kind of a drifting system is youíre not at the mercy of changes in water temperature or water quality, you can manoeuvre yourself, stay at the precise temperature for optimal growth and optimal health, you can manoeuvre yourself to avoid some of the problems that encounter traditional aquaculture on one fixed spot where for instance harmful algal bloom might be heading your way.

Cedric Morrison said at July 9, 2007 1:03 AM:

Re. everyone building mansions, part of the reason one builds a mansion is for the prestige of proving that one can afford to build a mansion. Most people can't make good use of so much space in terms of simply living and recreating in it.

Consider what happens when most people can afford a mansion. I believe it is quite possible that mansions will lose their signaling function, and people will find other ways to exhibit their wealth. If we are lucky, some of those ways will be constructive.

Brian Wang said at July 9, 2007 8:03 AM:

The promoters of vertical farming were noting that there were enough abandoned buildings which could be converted to the purpose of food supply.

also, a cooperative city government could zone certain air rights (permission to build X stories high) to encourage the activity of providing the vertical farming. Another way for a city to arrange vertical farming is to require it as part of a larger development.

Just like now the cities require a certain amount of parking and traffic and utility improvements. They could require builders of 100 story building which have a certain profitability to also supply a 30 story vertical farm to go along with the parking and other amenities.

Some of the economic encouragement for this is that supplying food locally would reduce the need for transporting the goods in.

Initially it would make sense to produce more high value product. Supply high end restaurants with fresher food. Provide food for the Whole foods and higher end groceries.

It would also make more sense where the city needed to replace, upgrade or add to sewer treatment. The vertical farms also processed waste water.

Randall Parker said at July 9, 2007 7:24 PM:


Energy is another obstacle for plant growth in tall buildings. You can put many layers of plants in a small land area. Some of the light hitting the sides of the buildings won't make it inside and the light won't shine all the way across each floor. The shadow of a tallk building takes far less land area (especially around noon) than the surface area of the plants on the many floors of the building. Also, each tall building in a city blocks light from hitting other buildings.

If nuclear reactors becoame cheap enough and the plants get artificial light 24 hours per day and 365 days per week then the skyscraper farms could drastically reduce the need for land for farming.

Bob Badour said at July 10, 2007 1:00 PM:


Picture a future where the tar sands run out, but the nukes for heating them remain. Just imagine how much food one could grow by filling in the hole with a multilevel underground farm using nukes to generate electricity for grow lamps etc.

Fort McMurray might replace California for year-round fresh produce. Then again, frozen produce might make more sense.

Randall Parker said at July 10, 2007 7:17 PM:


50 nuclear reactors in Alberta, paid for by tar sands oil sales, could power many industries. Would indoors growth of fruit and vegetables be the best use of that energy? Maybe.

California's going to lose a lot of farm land as immigrant-driven population growth pushes the population to 60 million people by 2050. So I'm expecting California farm output to decline even as its own local demand for food greatly increases.

I want to leave California before its population gets so big. Where to go?

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