Ringing the Alarm for Earth

   Ringing the Alarm for Earth
    By Tim Radford
    The Guardian UK

    Thursday 14 July 2005
Leading botanist Peter Raven calculates that species crucial to the
survival of the human race are in steep decline. Tim Radford meets a
man dubbed a 'hero of the planet.'

    Peter Raven is a botanist. He knows about photosynthesis, primary
productivity and sustainable growth. He knows that all flesh is grass;
that the richest humans and the hungriest alike depend ultimately on
plants for food, fuel, clothing, medicines and shelter, and that all of
these come from the kiss of the sun on warm moist soils, to quicken
growth and ripen grain.

    So botanists such as Raven begin with the big picture of
sustainable growth and can calculate to the nearest planet how much
land and sea it would take to sustain the population of the world if
everybody lived as comfortably as the Americans, British or French. The
answer is three planets.

    The global population is about to soar from 6 billion to 9 billion
in less than a lifetime. Around 800 million humans are starving, and
maybe 2 billion are malnourished, while 3 billion survive on two
dollars a day.

    Valuable agricultural land is being poisoned or parched or covered
in concrete, soils eroded, rivers emptied and aquifers drained to feed
the swelling numbers. Something has got to give, and the first things
to go are many of the plants and animals.

    By many, Raven means perhaps half to two thirds of all the other
species on the planet in the next 100 years. There could be 10m
different kinds of fern, fungus, flowering plant, arthropod, amphibian,
reptile, bird, fish and mammal on Earth. Nobody knows. People such as
Raven, director of the Missouri Botanic Gardens in St Louis, are doing
their best to count and preserve them.

    But the human population is growing at the rate of about 10,000 an
hour, and each human depends on a hectare or two of land and water for
what economists now call "ecosystem services" - the organisms that
ultimately recycle waste and deliver new wealth to provide oxygen,
fresh food, clean water, fuel, new clothes, safe shelter and disposable
income.

    Some of these organisms are now being chased to oblivion by human
population growth at levels that ecosystems cannot sustain.

    Ecosystems, he says, can be whatever you like. Hedgerows in
Hampshire are an ecosystem; so are weeds on a railway line at
Hammersmith. Savannahs, grasslands, prairies, rainforests, dry forests,
pine forests, uplands, heathlands, downlands, wetlands, mangrove
swamps, estuaries, oxbow lakes and coral reefs are all ecosystems, and
they survive on diversity. The greater the variety of microbes, plants
and animals in an ecosystem, the more resilient it is and the better it
works for all, including humans. So it would not be a good idea to
evict at least half of these creatures, especially if nothing is known
about them. But, Raven says, that is what is happening.

    There are ways of confirming species loss, even if it cannot be
established how many species there were in the first place. Look at the
vertebrates and molluscs in fossil records, Raven says, just for the
past 65m years or so. "You find that the average life of a species is
two to three million years and you get about one species per million
becoming extinct per year in the fossil record. Those particular groups
are a small sample, but they are a real sample," he says.

    "Then you can start with the literature in about 1600, when people
began to care enough about organisms to be able to document them well,
and for the groups that they were documenting - birds, mammals,
amphibians, reptiles, butterflies and plants - then you can say, 'What
was the rate over the past 400 years? It's tens of times or hundreds of
times the level it was before.'"

    That works out at hundreds of creatures per year over the past 400
years, and even more when humans, rats and other invaders started
colonising islands: 2,000 species have vanished from the Pacific basin
alone since the Polynesians got there 1,200 years ago.

    There is another way of checking, Raven says, pioneered by, among
others, sociobiologist and evolutionary psychologist Edward O Wilson.
There is a logarithmic relationship between the area of habitat and the
species that inhabit it. Measure a patch of forest and count a sample
of the species in it. Then compare it with another patch of forest 10
times smaller. The smaller one will have only half the sample species
count. This has been shown in thousands of individual observations, he
says. So destroying forests, piecemeal, is a way of extinguishing
creatures.

    There are various wild creatures that get along with humans and
follow them everywhere: cockroaches, fleas, ticks, rats, cats, pigs,
cattle, scavenger birds, lusty weeds. These invade little islands of
ancient biodiversity, take over, and see the natives off the premises.
And not just islands: one-third of all endangered plants in the
continental US are threatened because of alien invaders, Raven says. In
Hawaii, it is 100%.

    Global warming is not going to help, either. What happens to the
unique assembly of plants in the Cape region of Africa as the
thermometer rises? They cannot migrate south. There is no land south of
the Cape. So many will perish.

    Ecosystems are not static. They change, naturally. They burn, are
grazed or browsed, they regenerate, flood and silt up. But left to
themselves, they go on providing services that humans and other
creatures value. A mangrove swamp provides a habitat for shrimps. It
cannot be improved by draining it for a tourist beach, or building a
large city on it. Its natural value would be dissipated.

    "An ecosystem itself undamaged is very, very resilient, and the
more simplified it gets, the less resilient. Globally, what we are
doing is simplifying them all, simultaneously, which is a very
dangerous large-scale experiment," Raven says.

    Plants are a lifelong obsession of Raven - any plants. "I was so
excited and pleased by so many kinds of plants where I was first
getting used to them as a teenager, and even now I can look at
individual kinds of plants and be very, very excited.

    "The florid nature of a really beautiful orchid or some kind of
very rare plant that you see for the first time is really amazing.
There are some Chinese monkshoods, for example, in a garden outside my
office, and every year they come up and each time I see them I just get
completely excited by the intricacy of their flowers, and how beautiful
they are, and the fact that they are blooming.

    "Then when Isee photographs of really bizarre species of
monkshoods from high elevations in southern China, I just say, 'Oh my
gosh.' "

    Raven was born in China in 1936 and educated in California. "I grew
up in San Francisco and took plants and collected them - and then
through the rest of the Pacific states - and it never occurred to me
that things were becoming extinct rapidly. I thought of the world as a
natural place divided between cultivated and urban areas and what have
you, and in the 1950s, the global population was far less than half of
what it is now and certainly standards of affluence were nothing like
they are now. By the mid-1960s, we really began to think in terms of
environmental problems."

    Even then, the concerns were more about the domestic environment,
how people lived, the gap between rich and poor, and the dramatic, all
too visible swelling of the human investment. Population growth rates
were moving towards the highest percentages the world had ever seen.

    "I remember an article in the New Scientist in the mid-1960s, where
a physicist had calculated that at the rates of growth then prevalent,
in something like several hundred years the mass of human bodies would
be expanding away from the surface of the Earth at the speed of light,
which began to put a fine point on it," he says. "By the end of the
1960s, it was beginning to become evident that species were becoming
extinct rapidly."

    He got letters about extinction from Norman Myers (once a district
officer in Africa, now a professor at Green College, Oxford) which
provoked some serious thinking.

    In 1972, Raven chaired a National Science Foundation committee on
the future of systematic and evolutionary biology. By then, it was
obvious that tropical forests were being lost, and very rapidly. "Since
we knew far less about them than we did about organisms found anywhere
else, it was obvious that if we were going to derive biological
generalities and really understand the structure of life on Earth, we
needed to understand the interactions between them, the ways that they
evolved, whether the kinds of behaviours that took place in them were
like those in the well-known temperate communities or not," he says.

    Raven went from StanfordUniversity to the Missouri Botanic Gardens
in 1971, and began turning a small city recreation with one or two
researchers into a world-class research institution - mentioned in the
same breath as Kew and New York Botanic Gardens - with 50 scientists,
100 support workers and big research projects in places such as
Madagascar.

    He has, for the past three decades, been one of a highly vocal
scholarly group that has banged the drum for the environment. Time
magazine dubbed him a "hero of the planet". He can - and on public
platforms does - paint an alarming picture of the great human takeover;
the domination, by just one species, of a home fashioned by 3bn years
of evolution to be shared by 10bn species. The world is clearly
becoming more homogeneous, Raven says. "But the way I see it, we are
not dying. We are simply losing opportunities, and at some point we
have got to become sustainable. The choice is not whether we are going
to reverse things. They are not going to be reversed. The real choices
are where to stabilise it or how far to go."

    As he keeps pointing out, the human species is living as if it had
more than one planet to occupy. Forty years ago, at Stanford, he and
colleagues tried to calculate the economic cost of exporting humans to
a star system likely to be orbited by habitable planets. They worked
out that it would cost the entire gross economic product of the planet
to ship just 12 people a year to Proxima Centauri or beyond. His
message for the planet is, "Think, look at the big picture, and think
again".

    "If both the population and standards increase, then obviously you
come up with an impossible picture, which is a clear signal that we
must [change]. It is not a matter of choice, it is not a matter of
social justice alone, it is not a matter of morality, it is not a
matter of creating a sustainable world so that industrialised countries
can benefit from it.

    "We must reach a sustainable population level, sustainable levels
of affluence or consumption, and we must find technologies that replace
the ones we are using now."

    Life at a Glance

    Born: Shanghai, 1936.
    Education: Graduated, highest honours, Berkeley, 1957; doctorate,
Los Angeles, 1960.
    Career: Foreign member of more than 20 learned institutions,
including the Chinese and Indian Academies of Science, and the Royal
Society. First book was Native Shrubs of Southern California, 1966;
author of more than 480 books and papers. Director of Missouri Botanic
Gardens since 1971.
    Family: Married, with three daughters and a son, none of them
botanists.

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