X-Message-Number: 0023
Subject: Saving The Library Of Life

Date: 06 Mar 93 13:43:50 EST
From: Charles Platt <>
Message-Subject: CRYONICS Rainforest Plan

To: Cryonet

March 6, 1993

Some people may be aware of the plan proposed last year by 
Gregory Benford to freeze species which face extinction, 
especially in tropical rainforests where slash-and-burn is in 

With Benford's permission, I am posting the complete text of 
his paper (about 24 kilobytes). There is reason to hope that 
this very reasonable proposal by an accredited scientist will 
encourage a slightly more receptive attitude toward cryonics.

--Charles Platt



Gregory Benford
Department of Physics
University of California, Irvine
Irvine, CA   92717

FAX: 714-856-5903

office: 714-856-5147



A broad program of freezing species in threatened ecospheres 
could preserve biodiversity for eventual use by future 
generations. Sampling without studying can lower costs 
dramatically. Local labor can do most of the gathering. 
Plausible costs of collecting and cryogenically suspending 
the tropical rain forest species, at a sampling fraction of 
10-6, are about two billion dollars for a full century. Much 
more information than species DNA will be saved, allowing 
future biotechnology to derive high information content and 
perhaps even resurrect then-extinct species. A parallel 
program of limited in situ preservation is essential to allow 
later expression of frozen genomes in members of the same 
genus. This is a broad proposal which should be debated 
throughout the entire scientific community. 

     We have only begun the elementary taxonomic description 
of the world biota. While about 1.4 million species have been 
given scientific names, estimates of the total number of 
species range up to roughly 30 million or higher (1,2). 
Systematists may very well not know the species diversity of 
the world flora and fauna to the nearest order of magnitude. 
     Time is running out in which we can even catalog our 
living wealth. Though the overall extinction rate from fossil 
evidence is of order 10-7 species per species year (3), a 
very conservative estimate of the current extinction rate 
gives roughly 5000 species lost annually (4), with some 
values far higher (5,6). 
     We are accelerating toward a calamity unparalleled in 
planetary history. The best known cause of present day 
species extinction is the cutting of tropical forests, which 
have lost about 55% of their original cover and are shrinking 
at the rate of 1.8% per year (5). Worse, the rate seems 
doomed to increase, since its ultimate cause is human 
activity, and human numbers and expectations grow apace. To 
improve the lot of a swelling human tropical population would 
require at least a fivefold increase in economic activity 
there, bringing a crushing load on the already strained 
biosphere (6). 
     Other biological zones such a coral reefs and oceanic 
islands also dwindle at alarming rates. Because of the 
latitudinal species diversity gradient, losses are most 
severe in precisely the tropical continents where our own 
numbers swell so alarmingly (7). 
     Everywhere there are calls for a halt to tropical 
deforestation, but most voices seem tinged with despair. 
Ehrlich and Wilson suggest we could lose a quarter of all 
species in half a century, with incalculable effects on our 
biosphere (8). We now co-opt about 40% of plant growth 
worldwide, favoring monocultural crops, which must greatly 
affect genetic diversity. Given the blunt economic and 
cultural forces at work, even slowing the rate of destruction 
seems doubtful in the immediate future. 
     This dire moment demands radical thinking. In the spirit 
of a thought experiment, I discuss here a proposal which 
links the in situ preservation community, which emphasizes 
protected wild areas, and the ex situ conservationists such 
as zoos, botanical gardens, etc. For in situ measures there 
are economic, environmental and aesthetic arguments. To 
preserve the genome of many species, however, ex situ methods 
may suffice. Considering this possibility serves to separate 
the kinds of arguments we make for conservation methods, 
including concepts of our moral debt to posterity. In the 
spirit of sharpening debate by considering plausible 
scenarios, we can test our ideas. 

Salvage by Sampling     

     Our situation resembles a browser in the ancient library 
at Alexandria, who suddenly notes that the trove he had begun 
inspecting has caught fire. Already a wing has burned, and 
the mobs outside seem certain to block any fire-fighting 
crews. What to do? There is no time to patrol the aisles, 
discerningly plucking forth a treatise of Aristotle, or 
deciding whether to leave behind Alexander the Great's 
laundry list. Instead, a better strategy is to run through 
the remaining library, tossing texts into a basket at random, 
sampling each section to give broad coverage. Perhaps it 
would be wise to take smaller texts, in order to carry more, 
and then flee into an unknown future. 
     While efforts to contain and control our accelerating 
biodiversity disaster are admirable, and should be 
strengthened, it may well be time to consider a similarly 
desperate method of salvage. I propose that the biological 
community ponder a systematic sampling of threatened natural 
habitats, with long term storage by freezing. This would more 
nearly resemble an emergency salvaging operation than an 
inventory, for there would be minimal attention paid to 
studying the sample. The total sample mass might be reduced 
by judiciously trimming oft-repeated species of the prolific 
ants and beetles. (Duplication in sampling makes for good 
statistics, though, helps comparative anatomy, and may aid 
those for whom more successful species are more interesting.) 
The essential aim is to save what we can for future 
generations, relying on their better biological technology to 
extract the maximum benefit. 
     Sampling of tropical trees by insecticidal fogs and 
active searching of the canopy is common. Teams trained to 
simply collect, without analyzing, require minimal labor by 
research biologists. Freezing at the site can be done with 
ordinary ice or dry ice; liquid nitrogen suspension can occur 
only at the long-term repository. Extensive work by 
taxonomists enters only when samples are studied and 
classified. Here lies our current bottleneck. There are far 
too few taxonomists to tally the world's species within our 
generation (6), let alone analyze them. 
     We sidestep this problem if our primary aim is to pass 
on to later generations the essentials of our immense 
biodiversity. Even information about the existence of a 
species is useful, for without a sample, in the future one 
cannot be sure whether a given variation did not exist at 
all, or simply became extinct without being observed. Thus 
extensive taxonomic expertise would defeat the project. 
Detailing allelic variations within a population, or other 
variations (con-specific, interpopulation; congeneric; 
ecosystem, etc.) probably will not be worth the trouble. 
     It seems likely that captive breeding programs, parks, 
microhabitats and zoos can preserve only a tiny fraction of 
the threatened species. (Here I shall use the term 
"preservation" to mean keeping alive representatives of at 
least each genus--in situ, in vivo protection in reserves--
and argue that this is essential to eventually studying and 
potentially resurrecting frozen species.) 
     To save the biosphere's genome heritage demands going 
beyond existing piecemeal strategies of seed banks, of 
germplasm and tissue culture collection, and cryopreservation 
of gametes, zygotes and embryos; these programs mostly 
concentrate on saving traditional domesticated varieties (8). 
Our goal is a complete sample of all threatened species. 


     Much more than data about existence can be carried 
forward by simply preserving a wide sample at low 
temperatures. Banking cells by drying them with silica gels, 
for example, is useful for short times, but at room 
temperatures thermal damage to DNA will accumulate over the 
decades. We know that seeds can germinate after lengthy 
freezing, and that microbes can sustain cryogenic 
temperatures. Simple cells such as sperm and ova survive 
liquid nitrogen preservation and function after warming. 
Generally, organs with large surface/volume ratios preserve 
well, such as skin and intestines. 
     Of course, more complex systems suffer great freezing 
damage, though research proceeds into minimizing this. 
Several kinds of damage occur, and little is known about 
methods of reversing such injury. Biochemical and biophysical 
freezing injury arises from shrinking cell volume as freezing 
proceeds. Plants display extrusion of pure lipid species from 
the plasma membrane, as cells contract during freezing 
(9,10). Such lipids do not spontaneously return to the plane 
of the membrane during volume expansion on thawing, so that 
restoration of approximate isotonic volume near the melting 
point causes cellular lysis due to inadequate membrane 
surface area. While osmotic injury can be reversed (11), 
there is loss of membrane proteins (12). Reorganization of 
membrane bilayer structure into cylindrical lipid tubes may 
be reversible with warming (13, 14, 15). Structure of the 
cytoplasm may break down into blobs of proteinaceous matter 
(16, 17). Major fracturing of cells, axons, dendrites, 
capillaries and other elements causes extensive damage at 
temperatures below the glass point (18), suggesting that this 
be avoided. For some purposes, then, immersion in liquid 
nitrogen may be unacceptable. 
     The problem of recovering cells from frozen samples is 
complex, but even low survival rates of one cell in a million 
are irrelevant if the survivor cells can produce descendants. 
However, our minimum aim can be to simply retain DNA, the 
least we should expect from a sample--though of course, 
suspending whole creatures retains far more information. For 
this, liquid nitrogen is suitable for long term storage (-
196o C), especially since it is by far the cheapest method. 
At 25 cents/liter, liquid nitrogen is the lowest-priced 
commercial fluid, excepting water and crude oil. It allows 
suspension in large, easily tended vaults, simply by topping 
off the amount lost. Only a wholesale breakdown of industry 
can plausibly destroy the samples; no mere power failure will 
do. Redundant storage at different sites avoids even this. 
     Further, while neither liquid nitrogen nor freeze-drying 
damage DNA, freeze-drying does cause far more injury to 
structural and taxonomic characteristics. For the broad 
program envisioned here, which should also include tiny 
samples of ocean water with its teeming viruses and bacteria, 
plainly liquid nitrogen is essential. This is also true for 
saving whole creatures, since we also gain their parasites, 
bacteria, and viruses, which are better preserved 
     A crucial point is that we need not rely on present 
technology for the retrieval. Progress in biological recovery 
can open unsuspected pathways. 
     Recent advances underline this expectation. Techniques 
such as the polymerase chain reaction can amplify rare 
segments of DNA over a million-fold (19). Such methods have 
enabled resourceful biologists to recover specific segments 
from such seemingly unlikely sources as a 120-year-old museum 
specimen, which yielded mitochondrial DNA of a quagga, an 
extinct beast that looks like a cross between a horse and a 
zebra (20). A 5000-year-old Egyptian mummy has yielded up its 
genetic secrets (21). Amplifiable DNA in old bone is 
beginning to open study of the bulk of surviving organic 
matter from the deep past (22). The current record for 
bringing the past alive in the genetic sense is DNA extracted 
from a fossilized magnolia leaf between 17 and 20 million 
years old (23). This feat defied the prediction from in vitro 
estimates of spontaneous hydrolysis rates, which held that 
DNA could not survive intact beyond about 10,000 years (24). 
     We should recognize that future biological technology 
will probably greatly surpass ours, perhaps exceeding even 
what we can plausibly imagine. Our attitude should resemble 
that of archeology, in which a fraction of a site is 
deliberately not excavated, assuming that future 
archaeologists will be able to learn more from it than we 

Preserve the Genus, Freeze the Species

     We need a combined strategy to salvage biodiversity out 
of catastrophe. The best approach may be two-pronged: 
     (a) preserving alive some fraction of each ecosystem 
type ("biome"), its population intact at the genus level, and 
     (b) freezing as many species related to the preserved 
system as possible. 
     At a minimum, this will allow future biologists to 
extract DNA from frozen samples and study the exact genetic 
source of biodiversity. Genes of interest could be expressed 
in living examples of the same genus, by systematic 
replacement of elements of the genetic code with information 
from the frozen DNA. Obviously, the preserved genus is 
     These techniques would open broad attacks on the problem 
of inbred species. A ravaged environment can constrict the 
genetic diversity of individual species. Reintroducing 
diverse traits from frozen tissue samples could help such a 
species blossom anew, increasing its resistance to disease 
and the random shocks of life. 
     Beyond this minimum--the DNA itself--future biologists 
will probably find great use for recovered cells in re-
expressing a frozen genome. Cell use for mollusks, trees, 
insects etc. is a cloudy, complicated issue. For mammals, 
uterine walls, elements of the sexual reproductive apparatus, 
etc., should prove essential, since placentation and the 
highly variable physiology of different taxa are crucial. It 
seems highly unlikely that one can make appropriate placental 
and endometrial choices in the many steps from genome to 
newborn, merely from reading DNA. 
     As saviors of the "Library of Life" we are at best 
marginally literate, hoping that our children will be better 
readers, and wiser ones. Many biotechnological feats will 
probably emerge within a few decades--many ways, let us say, 
of reading and using the same genetic "texts." But no 
advanced "reader" and "editor" can work upon texts we have 
     This holds out the hope of selectively reintroducing 
biodiversity in the future, to gradually recover lost 
ecosystems. Individual species can be resurrected from very 
small numbers of survivors, as the nearly extinct California 
condor and black-footed ferret have been. 
     Fidelity in reproducing a genome may not be perfect, of 
course. Many practical problems arise (placenta environment, 
chemistry, etc.) which complicate expression of a genotype. 
In any case, future generations may well wish to edit and 
shape genetically those species within an ecosystem as they 
repair it, for purposes we cannot anticipate. 
     Loss of nearly all of an ecosystem would require a huge 
regrowth program, for which the Library of Life would prove 
essential. Suppose, though, that we manage to save a large 
fraction of a system. Then the species library will provide a 
genetic "snapshot" of biodiversity at a given time and place, 
which evolutionary biologists can compare with the system as 
it has evolved much later -- for example, through perhaps 
thousands of insect generations. This would be a new form of 
research tool. 
     Already a crash program to collect permanent cell lines, 
DNA, or both from vanishing human populations has excited 
attention (25). This program maintains cell lines by 
continuous culture, a costly method which invites random 
mutation. Such records may allow a deeper understanding of 
our own origins and predispositions (26), but banking frozen 
tissues of endangered species is the only way to ensure that 
any genetic disease diagnosed in the future in small, closed 
populations (the "founder effect") can be mapped and managed 
(27). Ehrlich suggested creation of "artificial fossils" in 
such fashion (28). The "frozen zoo" of San Diego, begun with 
this in mind (29), has immersed 2400 mammal fibroblast cell 
cultures and 145 tissue pieces in liquid nitrogen--about 300 
species, in all. Cryonic mouse embryo banking for genetic 
studies is now routine (30). 
     The far larger prospect of eventually reading and using 
a Library of Life is difficult for us to imagine or 
anticipate, at the early stages of a revolution in biological 
technology. Our situation may resemble the Wright brothers if 
they had tried to envision a moon landing within three 
generations. Can We Afford It? 
     This sweeping proposal avoids the problem of deciding 
which species are of probable use to us, or are crucial to 
biodiversity. By sampling everything we can, we avoid some 
pitfalls of our present ignorance. Too often, preservation 
efforts focus on "charismatic vertebrates," neglecting the 
great bulk of diversity (8). 
     Many conservationists may be reluctant to support a 
cryopreservation campaign, because they fear it will sample 
too sparsely. This assumes that present taxonomic methods and 
costs are necessary. But an important feature of this 
proposal is that the samples need not be studied as they are 
taken. This avoids the scarcity of taxonomists, speeding 
field work and lowering costs. Plausibly, much of the 
gathering can be done with semi-skilled labor. 
     This suggests immediately that the bulk of the funding 
come from "debt swap" between tropical and temperate nations, 
as has been used to "buy" rain forests and set them aside 
from cutting (8). Further, this will create a local work 
force which profits from controlled, legal forest work, 
rather than from cutting it. 
     As a very rough estimate, consider a sampling program 
which collects all life forms from a stand of a hundred 
trees, but not the trees themselves, for each hundred square 
kilometers of rain forest, i.e., a sampling fraction in the 
range of 10-6. If this costs on average ten thousand dollars 
per stand (probably an overestimate), then a million square 
kilometers yields 104 stand-samples costing 108 dollars. For 
all the world's tropical forests, covering about nine million 
kilometers, the cost is close to a billion dollars. 
     To suspend such samples requires replacing boiled-off 
liquid nitrogen. Suppose we collect ten kg. from each tree, 
or about 107 kg. for a million-kilometer area. Current 
nitrogen loss costs of a mass M presently obey a scaling law, 

           cost/year =  $400/year (M/100 kg.)2/3

since nitrogen loss scales with surface area. To suspend the 
stand-samples for all the tropical forests then demands 3.7 x 
106 dollars/year, or 0.37 billion dollars for a century. A 
similar argument suggests that building the repository, 
curatorial labor, etc. will probably require comparable 
costs, especially if the samples are to be readily available 
to researchers, with detailed labeling. Thus an estimate of 
perhaps a billion dollars for a century's storage seems 
plausible. Added to the collecting cost, we need in sum about 
two billion dollars. Current outstanding debt by tropical 
nations well exceeds a hundred billion dollars. 
     Of course, this does not touch upon side costs in 
training biologists, transport, perhaps doing some taxon 
discrimination, etc. Certainly the effort compares in cost 
with the Human Genome Project. The task is monumental; so is 
the plausible benefit. 
     Traditional economics cannot deal with transactions 
carried out between generations. As Harold Morowitz has 
remarked, the deep answer to "How much is a species worth?" 
is "What kind of world do you want to live in?" (31). 
     This drastic proposal does not address many legitimate 
reasons for preserving ecospheres intact, and it should not 
be seen as opposing them. Indeed, only by preserving in vivo 
a wide cross section of biota can we plausibly use much of 
the genetic library frozen in vitro. 
     An obvious possibility is that preservation of habitat 
may compete politically with a sampling and freezing program. 
There is no intrinsic reason why this need be so. They are 
not logically part of a zero-sum game because they yield 
different benefits over different time scales. Of course we 
would all prefer a world which preserves everything. But the 
emotional appeal of preservation should not disguise the 
simple fact that we are losing the battle, or to argue 
against a prudent suspension strategy. 
     Further, sampling is far less expensive than 
preservation--which is why it is more likely to succeed over 
the long run. Even competition for 'debt swap' funds will not 
necessarily be of the same economic kind. Conservationists 
seek to buy land and set up reserves, putting funds into the 
hands of (often wealthy) landowners. A freezing program will 
more strongly spur local, largely unskilled employment, 
affecting a different economic faction. 
     Sampling and freezing have little aesthetic appeal. To 
some they will smack of fatalism; it may be merely realism. 
As well, freezing species does not offer the immediate 
benefits which preservation yields. (Samples would probably 
be taken only from areas not already highly damaged.) More 
concretely, this proposal will not hasten benefits from new 
foods, medicines, or industrial goods. It will not alter the 
essential services an ecosphere provides to maintenance of 
the biosphere. We should make very clear that this task is 
explicitly designed to benefit humanity as a whole, once this 
age of rampant species extinction is over. 
     Some will see in this idea a slippery slope: to 
undertake salvaging operations weakens arguments for 
biodiversity preservation. To avoid this, the two parallel 
programs of preservation and freezing must be kept clear. In 
this sense the analogy to the library at Alexandria is false-
-for us, there is no true conflict between fighting the fire 
and salvaging texts. Further, in the real world, funds for 
conservation of DNA today do not come directly from in situ 
programs. If the Topeka Zoo budget is cut, the city does not 
transfer funds to Zaire to save gorillas. 
     Indeed, one can make the opposite argument -- that the 
spectacle of the scientific community starting a sampling 
program will powerfully illuminate the calamity we face, 
alerting the world, stimulating other actions. Beginning with 
local volunteer labor and contributions -- say, with the 
Sierra club sampling the redwood habitat -- could generate 
grass-roots momentum to overcome the familiar government 
inertia. In larger campaigns, by requiring that samplers 
accompany all legal logging operations, we can help develop a 
local constituency for controlled harvesting. 
     Perhaps the most difficult argument to counter is 
basically an unspoken attitude. As scientists we are trained 
to be careful, scrupulous of overstating our results, wary of 
speculation--yet these militate against the talents needed to 
contemplate and prepare for a future which can be 
qualitatively different from our concrete present. 
Paradoxically, we scientists labor to bring about this 
changed future. Now is the time to bank on the expectation 
that we will probably succeed. 
     Leading figures in biodiversity argue that a large scale 
species dieback seems inevitable, leading to a blighted world 
which will eventually learn the price of such folly (6, 8, 
30). The political impact of such a disaster will be immense. 
Politics comes and goes, but extinction is forever. We may be 
judged harshly by our grandchildren, our era labeled the 
Great Dying or the Age of Appetite. 
     A future generation could well reach out for means to 
recover their lost biological heritage. If scientific 
progress has followed the paths many envision today, they 
will have the means to perform seeming miracles. They will 
have developed ethical and social mechanisms we cannot guess, 
but we can prepare now the broad outlines of a recovery 
strategy, simply by banking biological information. 
     Such measures should be debated, not merely by 
biologists, but by the entire scientific community and 
beyond, for all our children will be affected.  These are the 
crucial years for us to act, as the Library of Life burns 
furiously around us, throughout the world. 


     I am indebted to those who contributed valuable comments and
ideas to this proposal: Mark Martin, Oliver Morton, Steve Harris,
David Brin, Oliver Ryder, Kurt Benirschke, Harold Morowitz,
Murray Gell-Mann, Gregory Fahy, Hugh Hixon, Michael Soule',
Francisco Ayala and Bruce Murray.


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