After four and a half billion years of inter-dependencies, the life on Earth is a complex ecological system or ecosystem. As it turns out, some physical parameters make for greater quantities of life. A tropical rain forest is a good example. Other locations are almost barren of life, such as the Antarctic.
Biodiversity is a word that conveys the richness of the disparity of life. Land with many species and specimens has a high biodiversity. This occurs where energy is abundant and is readily mobile. Estuaries, tree tops and swamps have high biodiversity. Where there is little energy or little capacity to move energy about, there are few species and specimens.
Humans have usurped land with the richest supplies of energy. In so doing, they have removed the indigenous flora and fauna. This removal of the competition is a step in the direction of a future that allows only for life that provides a benefit to people. The following map provides and indication of our influence. It shows biodiversity hot spots; the richest and most threatened areas of the world.
Plans for the future can use land characteristics to determine energy levels. Associating ecosystems with land cover and with energy deposition can provide and indication of the amount of energy that is available and can be sustainably appropriated. The following map and table give and indication of our current knowledge.
|Id||Region||Area sq.m.||Cell count||percent|
|20||Major Woods-Main Taiga||15571041627.412062||414||0.00%|
|21||Major Woods-Main Taiga||5538192477539.941406||139371||1.38%|
|22||Major Woods-Other Conifer||3102704024062.733887||60725||0.60%|
Major Woods-Mixed: Decid & Evergrn Broad Lf with
Major Woods-Mixed: Decid & Evergrn Broad Lf with
|25||Major Woods-Temp Broad Lf Forest||780287115971.479248||14759||0.15%|
|26||Major Woods-Temp Broad Lf Forest||712378712833.701538||11636||0.11%|
|27||Major Woods-Other Conifer||402802513310.048279||6546||0.06%|
|29||Major Woods-Trop/Subtrop Broad Lf Humid frst||6162632446114.984375||79817||0.79%|
|30||Non Woods-Cool/Cold Farms/Towns||2959862698549.866699||57507||0.57%|
|31||Non Woods-Warm/Hot Farms/Towns||9309647348894.322266||143007||1.41%|
|32||Major Woods-Trop/Subtrop Dry frst and Woodld||4714611523027.708984||61804||0.61%|
|33||Major Woods-Trop/Subtrop Broad Lf Humid frst||4250460429679.579102||54125||0.53%|
|36||Non Woods-Irrigated Paddylnd||1987885037439.005859||27453||0.27%|
|37||Non Woods-Other Irrigated Drylnd||1204215951987.350586||17621||0.17%|
|38||Non Woods-Other Irrigated Drylnd||284208608067.502075||4880||0.05%|
|39||Non Woods-Other Irrigated Drylnd||84052062887.436249||2007||0.02%|
|40||Non Woods-Main Cool Scrub & Grassld||3943879596164.254883||74347||0.73%|
|41||Non Woods-Main Warm/Hot Scrub & Grassld||17281753920109.261719||249837||2.47%|
Non Woods-Tibetan, Siberian Cold Grass/Stunted Wood
|43||Interrupted Woods-Trop Savanna & Woodld||6717216465060.143555||87037||0.86%|
|44||Wetld/Coastal-Major Bog/Mire, Cool/Cold Climates||974049034298.122925||22510||0.22%|
Wetld/Coastal-Major Warm/Hot Mangrove/Tropical Swamp
|46||Interrupted Dry Woods-Mediterranean types||1001897102499.186401||15630||0.15%|
|47||Interrupted Dry Woods-Other Dry & Highld wds||2594651830663.824707||38087||0.38%|
|48||Interrupted Dry Woods-Semiarid Woodld & Low Frst||907562417199.618164||12612||0.12%|
|49||Non Woods-Nonpolar Sparse (rocky) Vegetation||16583263310.775343||222||0.00%|
|50||Non Woods-Nonpolar Sand Desert||5224729037072.687500||75477||0.75%|
|51||Non Woods-Other Nonpolar Desert & Semidesert||10945523633729.777344||157360||1.55%|
|52||Non Woods-Nonpolar Cool Semidesert Scrub||2001583803636.694824||36217||0.36%|
|55||Interrupted Woods-Trop/Temp wds, Fields, Grass, Scrub||1213730638498.606445||24058||0.24%|
Interrupted Woods-2nd grow Trop/sub Trop, Humid/temp/boreal
Interrupted Woods-2nd grow Trop/sub Trop, Humid/temp/boreal
|58||Interrupted Woods-Trop/Temp wds, Fields, Grass, Scrub||2862917892459.063965||41620||0.41%|
|59||Interrupted Dry Woods-Succulent & thorn||3960416798810.236328||52661||0.52%|
|60||Major Woods-Southern Taiga||1141925938973.127930||26045||0.26%|
|61||Major Woods-Southern Taiga||454631805719.985657||9375||0.09%|
|62||Interrupted Woods-North/Maritime Taiga, subalpine||4353694475333.803223||123731||1.22%|
|63||Non Woods-Wooded Tundra Cold Grass/Stunted Wood Complex||1755574562241.592285||48608||0.48%|
|64||Non Woods-Heath & Moorland||150965279690.782806||2842||0.03%|
|65||Wetld/Coastal-Shore and Hinterland Complexes||346743177268.794556||5576||0.06%|
|66||Wetld/Coastal-Shore and Hinterland Complexes||271643838092.094574||4012||0.04%|
|67||Wetld/Coastal-Shore and Hinterland Complexes||227736876864.228302||3687||0.04%|
|68||Wetld/Coastal-Shore and Hinterland Complexes||158688278350.119598||2498||0.02%|
|69||Non Woods-Polar or Rock Desert||537498290159.993896||33652||0.33%|
|71||Non Woods-Other Nonpolar Desert & Semidesert||92485282559.789078||1463||0.01%|
Using simpler headings, the FAO appoint the land surface of Earth as follows. Values are in hectares as for 2005, database accessed 2009 February.
13 432 420 000
13 013 475 400
|Agricultural area||4 967 579 500|
|Arable and Permanent Crops||
1 561 681 000
1 421 169 100
140 511 700
3 405 897 000
|Forest and Woodland||
3 952 025 700
|All other land||
4 092 972 400
429 928 000
See UFZ – 2013.
In order to assess the global impacts of land use on the environment and help provide appropriate countermeasures, a group of researchers under the leadership of the Helmholtz Centre for Environmental Research (UFZ) has created a new world map of land use systems. Based on various indicators of land-use intensity, climate, environmental and socio-economic conditions, they identified twelve global patterns called land system archetypes.
Click on map for greater definition.
Once we've exhausted the fossil fuels, we'll need to find our energy from other sources. Vegetation lies at the base of the ecosystem and it can provide energy whether wood for fires or fruit for eating. Vegetation is also refereed to as net primary production or NPP.
The following maps give an idea of the degree of impact that we have on the land surfaces of Earth. Obviously any appropriation that is greater than the rate of replenishment is not sustainable. If we use 100% or more of the net primary production, then the vegetation can not replenish and it will perish. Thus, it cannot collect any more energy from the Sun for us to use. The sustainable level of appropriation is likely much less than 100%. Yet, from the first map, we see that huge swathes of the most productive land are having their energy stores directed to human usage.
Today, the energy source is mainly fossil fuels. However, once they are exhausted we will need get our energy from elsewhere. Vegetation will become the most likely source. These maps show that this future is unsustainable hence would not make a good plan. Alternatives aren't obvious.
Human appropriation of net primary production (NPP) as a percentage of the local NPP.
Global distribution of resource consumption as measured by the amount of net primary production (NPP) appropriated by humans.
The news is no better for the ocean resources as shown in the following depiction of change from 1966 to 2009 in use of primary production.
People need energy to power their bodies. This is biological energy. The more people that there are on Earth, the greater is their biological need. The following figure and table shows the increasing need based upon the standard 10 MJ energy per day requirement. This is about 3.65 x 109 Joules per year.
The graph shows the story, the numbers give structure to any planning.
|Year||Population||Annual Energy Needs (x1010 MJ)|
Values found on the U.S Census Bureau;
4. The Trophic Pyramid
Energy is essential for life on Earth. It flows through levels of the ecosystem. However, the flow is not very efficient. Even after millions of years of genetic improvements, there's still only about a 10% transfer of energy from one level of the pyramid to a higher level. The shape of a pyramid highlights this poor transfer rate but also highlights the dependence of one level to its supporting level underneath. The trophic pyramid is fundamental to life and is a valuable relation when considering energy allocations in the future.
The ecosystem's trophic pyramid is shown below.
At the base of the pyramid are the autotrophs. These living things capture their energy needs directly from the Sun. Most of the plants about us are autotrophs. People are not as people cannot convert the Sun's radiation into a form that would power their bodies.
The next step up the pyramid is allocated to the herbivores. These creatures, munch on the plants. In so doing they capture their energy needs from the energy stores within the plants. Some people are pure vegetarians. Because of this, they live at this level of the trophic pyramid. Given the efficiencies of energy conversion, herbivores capture only about 10% of the plants energy stores.
The next step up the pyramid is allocated to the carnivores. These creatures, eat other animals. Some special cases like people and bears eat both vegetation and other animals. This merits giving them the name omnivore. Again because of efficiencies, meat eaters capture only about 10% of the energy stores in the herbivores. But this represents 1% of the original energy in the plants. Given this poor energy transfer efficiency, it is no wonder that carnivores are greatly outnumbered by herbivores who themselves are greatly outnumber by vegetation.
Sitting at the top of the pyramid are the tertiary consumers. These creatures feed on the carnivores. This seems unrealistic as most people believe that carnivores and more specifically, themselves, are at the top of the pyramid. However, there are huge quantities of tiny little creatures that feast on any dead creature. These are called saprotrophs. These little critters eat the dead which still contain large quantities of energy. As well, these creatures release the chemicals of the body so that they can be used in other bodies. Again considering efficiencies, only 10% of the dead creature or about 0.1% of the originating plant's energy is captured by the saprotrophs, yet their usefulness is unquestionable.
We know the total amount of energy and energy transfer efficiencies. With these we can calculate the maximum possible number of creatures at each level of the pyramid. This calculation facilitates future planning.
Humans convince plants to grow and grow more in places that have never seen
the plant grow naturally. With the aid of two contrived components, water and
fertilizer, we can plant a seed and calmly, reasonably expect the plant to
provide nurture. Usually its many more seeds than what where originally planted.
The International Fertilizer Industry Association (IFA) tabulates a usage of 140 megatonnes (Mt) in the year 2002. The following table
show the relative amount.
Table 1: Fertilizer Components
There is no doubt that adding these components increases the crop yield. But, there’s a maximum benefit (see ). And there’s a cost to making or gathering the fertilizer and depositing it on the ground. The European Fertilizer Manufacturers Association (EFMA) paints a rosy picture. They indicate an energy production cost for the fabrication of Nitrogen as in the following (see).
Table 2: Nitrogen Production Cost
|1910||Birkeland-Eyde Electric Arc||400|
|1975||Steam Reforming Natural Gas||50|
In their example, they use wheat as the seed. By experimentation, they determined an optimum application of 170 kg N per hectare. This yielded 8.2 tonnes per hectare (having absorbed 126 GJ of solar energy). Without Nitrogen, the yield was 3.5 tonnes per hectare (with 71 GJ of solar energy captured).
Next, they wish that all 16.8 million hectares used for growing wheat used this optimum application of Nitrogen. They believe that the result is a yield of 252 GJ worth of biomass with 126 GJ of grain (ie seed) and 126 GJ of straw.
Also, by their estimate, the energy cost for the production, transportation and spreading of Nitrogen is 40, 1, and, 3 GJ per tonne respectively. If 8.2 tonnes are applied to one hectare, the total cost is 360.8 GJ/ha. This results in an increase of 55 GJ of solar energy or an energy benefit of 0.15. Presumably this doesn’t take into account the cost to harvest the wheat, deliver the wheat to manufacturers, mill the wheat into flour and make the flour into food. But, it is a good indicator.
6. Frying Mushrooms
People, in addition to hobbits, seek out mushrooms for their wonderful tastes. Coming in many exotic shapes and colours, these culinary treats can bring excitement to many a dinner plate. Caution must always be practised as so many mushrooms are toxic and can kill whether from touch or from ingestion. But getting a bit of education so as to learn which are safe is a small price to pay so as to savour these treats.
Typical mushrooms have a paltry 18 kcal of energy per 70 grams or 1.1e6 Joules per kilogram according to the USDA. Frying these wonders on the stovetop for 20 minutes at medium temperature (about 1000 watts) consumes 1.2e6 Joules of electrical energy. Hence, frying mushrooms takes more energy than what they provide to us. They’re a net energy loss. And, this doesn’t account for hiking in the woods to pick the mushrooms, effort to clean the mushrooms, building the stove and generating the electrical power to heat the stovetop element.
According to the law of entropy, every activity results in a net energy loss as with our mushroom example. How will we decide which activities are worth the energy expenditure and which aren’t?