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Preventing global famine in case of sun-blocking scenarios: Seaweed as an alternative food source Key findings

Authors:

Abstract

This research suggests that in a sun-blocking scenario which could lead to an agriculture collapse, seaweed can be scaled up within 3-6 months to meet global food demands. The resulting retail price would be less than 2 $/kg making it affordable for the global population, potentially contributing to saving hundreds of millions from starvation. To achieve the task of feeding everyone, hundred thousands of square kilometers or less than 0,2% of the ocean surface would need to be covered with these farms. The limiting factor for expansion is expected to be the twisting of synthetic fiber into rope, since seaweed farms consist mainly of twine. The global rope production would need to be increased by a factor of 400. Disclaimer This is a draft of an ongoing research project. Findings may vary from final publication.
Preventing global famine in case of sun-blocking
scenarios: Seaweed as an alternative food source
A. Mill
*,1
, C. S. Harrison
2
, S. James
3
, S. Shah
1
, T. Fist
1
, K. A. Alvarado
1,4
, A. R. Taylor
1
, D.
Denkenberger
1,4
1
Alliance to Feed the Earth in Disasters,
2
University of Texas, Rio Grande Valley,
3
Baylor
University,
4
University of Alaska, Fairbanks
Key findings
This research suggests that in a sun-blocking scenario which could lead to an agriculture
collapse, seaweed can be scaled up within 3-6 months to meet global food demands. The
resulting retail price would be less than 2 $/kg making it affordable for the global population,
potentially contributing to saving hundreds of millions from starvation. To achieve the task of
feeding everyone, hundred thousands of square kilometers or less than 0,2% of the ocean
surface would need to be covered with these farms. The limiting factor for expansion is
expected to be the twisting of synthetic fiber into rope, since seaweed farms consist mainly of
twine. The global rope production would need to be increased by a factor of 400.
Disclaimer
This is a draft of an ongoing research project. Findings may vary from final publication.
1. Why humanity needs quickly scalable alternative foods
Humanity is vulnerable to extreme scenarios such as asteroid impacts, super volcanoes, or
even full-scale nuclear war. Although the initial death toll could total hundreds of millions, most
of the danger lies with indirect consequences. The resulting fires and eruptions would launch
soot into the atmosphere where it could block most of the sun's radiation for up to a decade,
cooling the planet and limiting photosynthesis. These nuclear or volcanic winters would render
conventional agriculture ineffective. The ensuing famine could cost billions of lives and
cascading effects could cause irreparable damage to the long-term future of humanity. Current
food storage provides only a few months’ leeway to solve this problem and would be expensive
to expand.
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2. Modelling scale-up in nuclear winter
To see if seaweed is a promising alternative food source in sun-blocking scenarios, a Global
Earth System model was taken to provide environmental parameters, which were then taken to
calculate seaweed production rates. The material requirements for the seaweed farms are
compared to industrial capacities. A Geographic Information System (GIS) analysis shows the
available ocean area.
2.1 Global Earth System
It is estimated that a full-scale nuclear war between the US and Russia could inject 150
teragrams (Tg) of soot into the atmosphere. The 1st May of 2020 was chosen as starting point.
This would be particularly bad timing because at this time of the year the food storage is low
and the following harvests of that year could be destroyed.
The graph below shows the global average Photosynthetically Active Radiation (PAR, blue line)
that is hitting the earth’s surface and the resulting Net Primary Production (NPP, black line). The
dotted lines represent a control run in which no nuclear war occurs.
A strong link is visible between the amount of sunlight hitting earth and the production of
biomass, represented through the amount of carbon fixed in plants. Following a 150 Tg event, a
rapid fall in both PAR and NPP can be observed.
As a consequence of the sun being blocked the upper ocean layers start cooling (though slower
than the surface on land). These colder layers increase in density and sink down, lifting up more
nutrient-rich waters. Because of this deep ocean mixing some regions even experience an
increase in NPP in a nuclear or volcanic winter despite the lack of radiation (blue areas in next
image). The right graph displays the NPP of the Sargasso region (east of North America) where
the deep ocean mixing supplies the region with nutrient rich waters for several years before
normalizing (solid line depicts nuclear winter run and dotted line represents the control run).
2
2.2 Seaweed Growth Model
Ocean Surface Temperature, Salinity, PAR and Nutrient Levels are used to calculate the
production rate of the seaweed species Gracilaria tikvahiae
. The calculations show that growth
rates of over 20% per day for the first 6 months can be achieved in several Large Marine
Ecosystems (LMEs), allowing for quick scaling up. At these rates the global food demand can
be covered by seaweed within 3-6 months, outcompeting all conventional high-yield crops like
corn even in a nuclear winter. 160% of global food demand was chosen as the production limit
to account for food waste and some animal feed.
The impacts of the growth parameters on the production rate can be seen on the next page.
One key aspect is the growth limitation depending on the incoming light. For this seaweed
species, 20 W/m² is sufficient to reach maximum growth capabilities, which is approximately the
lowest point in the 150 Tg model). This is the reason why various types of seaweed can be
found flourishing several meters under the water surface and this makes them an ideal crop for
low-sunlight scenarios like a volcanic or nuclear winter.
The density limitation shows the decrease in growth due to overshadowing. From this value the
ideal harvest frequency is estimated and taken into labour considerations.
3
Production Rate
(I) (T) (v) (S) (ρ)P=PM*f*g*h*i*j
Light Limitation
Temperature Limitation
Nutrient Limitation
Salinity Limitation
Density Limitation
4
2.3 Geographical Information System (GIS)
Based on these growth rates the required areas of ocean surface can be estimated.
To calculate the suitable ocean area for these farms, a GIS analysis was done, with the
limitations shown in the table below.
Area Limitation
Reasoning
Between latitudes 30°N and
30°S
Most promising Growth rates
46 km radius around harbors
Common range for economical aquaculture farming
2 km belt around coasts
Accessible area usable without port infrastructure
Less than 100 m water depth
Reduces the anchoring cost of the seaweed farms
The resulting ocean area spans over 1.9 million km², providing enough room to place the
required 0.3 to 0.6 million km² of farms.
2.4 Industry scope
These seaweed farms’ main components are ropes. To cover the area to meet global food
demand, 6 to 12 million tonnes of rope need to be twisted and deployed. Current global
production accounts for only 0.2 million tonnes of rope per year with the limiting factor being the
twisting of synthetic fibers of which 66 million tonnes are produced globally each year. Since
time is of the essence to prevent a global famine, rope twisting capacities need to be scaled up
dramatically. To twist all of the synthetic fiber production ~320.000 twisting machines would be
needed, thus increasing the rope production rate by a factor of 400. With increased demand and
rapid tooling cost this requires ~$7 billion for the machines, an amount which is dwarfed by
5
material and labour costs). This endeavour might seem tremendous but it would occur at a
much smaller scale than the retrofitting of car manufacturers in World War 2 to produce planes
instead.
3. Conclusion
The specific properties of seaweeds allow for rapid scaling up even in extreme scenarios like
nuclear or volcanic winters. This is especially crucial for the long-term future of humanity to
bridge the gap between a global agricultural collapse, after which we will rely on food storage
which only lasts several months, and the switch to other alternative food sources that could take
years to scale up.
Several assumptions have been made throughout this research project to achieve the holistic
potential of seaweed. Please consider subscribing to the ALLFED newsletter to receive updates
when the final and more detailed publications are online.
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Further questions?
Aron Mill
Research Associate
aron@ALLFED.info
Sahil Shah
Financing, Reinsurance, Seaweed Investment & Operations
sahil@ALLFED.info
6
... Post-disaster scenario analysis was based on the Coupe et al. [22,37] in-depth nuclear winter climate model. In their study, 150 Tg of soot are projected above the clouds, where rain cannot wash it out [22,38]. The subsequent climatic consequences, such as large drops in temperature and precipitation levels, were used as a basis to understand how the food system might be altered in this scenario, rather than as direct mathematical inputs. ...
... The catastrophe strikes in May, which is likely a worst-case scenario. Models suggest that the climactic effect of particle emissions is larger during this period; additionally, food stocks are at their near lowest in the global North, as the Northern hemisphere harvest season has not yet started, and could potentially fail [38]. The results found using this model are also, to some extent, applicable to the volcanic winter scenario [22,37,39], even though the soot aerosols from nuclear fires result in more extreme climate effects. ...
... Seaweed can grow with low sunlight [49] and would be protected from ultraviolet light possibly generated by a nuclear winter [50]. Developing seaweed farming has been proposed as a potentially very significant contribution to the dietary intakes of the global population in this situation [38]. Seaweed consumption has been advocated by the FAO for decades [51][52][53]. ...
Article
Full-text available
Abrupt sunlight reduction scenarios (ASRS) following catastrophic events, such as a nuclear war, a large volcanic eruption or an asteroid strike, could prompt global agricultural collapse. There are low-cost foods that could be made available in an ASRS: resilient foods. Nutritionally adequate combinations of these resilient foods are investigated for different stages of a scenario with an effective response, based on existing technology. While macro- and micronutrient requirements were overall met, some—potentially chronic—deficiencies were identified (e.g., vitamins D, E and K). Resilient sources of micronutrients for mitigating these and other potential deficiencies are presented. The results of this analysis suggest that no life-threatening micronutrient deficiencies or excesses would necessarily be present given preparation to deploy resilient foods and an effective response. Careful preparedness and planning—such as stock management and resilient food production ramp-up—is indispensable for an effective response that not only allows for fulfilling people’s energy requirements, but also prevents severe malnutrition.
... nuclear winter), the cost of storing sufficient food for the global population is estimated to be extremely high in comparison to producing resilient foods that require less or no sunlight (Denkenberger and Pearce, 2015;Denkenberger et al., 2019). For example, in an ASRS cool-tolerant crops could be relocated to more adequate climates (Pham et al., 2022), simple greenhouses could be built on the tropics (Alvarado et al., 2020) and global seaweed production could be quickly ramped up (Mill et al., 2019), sugar could be produced from lignocellulosic biomass (Throup et al., 2022), synthetic fat could be produced from hydrocarbons , acetic acid could be produced from CO 2 via microbial electrosynthesis (García Martínez et al., 2021a), mushrooms could be grown on residue from logging, cellulose-digesting ruminants and insects could be used as a food source (Denkenberger and Pearce, 2015), and leaf protein concentrate could be obtained . This work studies the use of microbial protein produced via methanotrophic bacteria as a potential component of a food-crisis response. ...
... Methane SCP is generally faster to ramp up compared to other industrial solutions for resilient food production in ASRS, such as new construction of lignocellulosic sugar plants (Throup et al., 2022) or H 2 SCP plants (García Martínez et al., 2021b). Other non-industrial, low-tech resilient food solutions such as tropical greenhouses (Alvarado et al., 2020) and seaweed farming in the ocean (Mill et al., 2019) are expected to scale up production faster. However, the high protein content and quality of the methane SCP product far surpasses that of these faster scaling solutions, making it valuable as a protein supplementation food during a GCFS. ...
Preprint
Full-text available
A catastrophe such as supervolcanic eruption, asteroid impact or nuclear winter could reduce global food production by 10% or more. Human civilization’s food production system is unprepared to respond to such an event, and current preparedness centers around food stockpiles, an excessively expensive solution given that a global catastrophic risk (GCR) scenario could hamper conventional agriculture for 5 to 10 years. Instead, it is more cost-effective to consider alternative food production techniques requiring little to no sunlight.This study analyses the potential of single-cell protein (SCP) produced from methane (natural gas) as an alternative food source in the case of a catastrophe that considerably blocked sunlight, the most severe food shock scenario. To determine its viability, the following are quantified: global production potential of methane SCP, capital costs, material and energy requirements, ramp-up rates and retail prices. In addition, potential bottlenecks to fast deployment are considered.While providing a higher quality of protein than other alternatives, the production capacity would be slower to ramp up. Based on 24/7 construction of facilities, 7-11% of global protein requirements could be fulfilled at the end of the first year. Results suggest that investment in production ramp up should aim to meet no more than humanity’s minimum protein requirements. Uncertainty remains around the transferability of labor and equipment production, among other key areas. Research on these questions could help reduce the negative impact of potential food-related GCRs.
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