In 1981, when I was in my mid-twenties, I climbed Mt Albert Edward, one of the
highest peaks on the verdant island of New Guinea. The bronzed grasslands
were a stark contrast to the green jungle all around, and among the tussocks
grew tree-ferns whose lacy fronds waved above my head.
Downslope, the tussock grassland ended abruptly at a stunted, mossy forest. A
single step could carry you from sunshine into dank gloom, where the
pencil-thin saplings on the margin were so festooned with moss, lichens and
filmy ferns that they ballooned to the diameter of my waist. In the leaf
litter on the forest floor I was surprised to find the trunks of dead
tree-ferns. Tree-ferns grew only in the grassland, so here was clear
evidence that the forest was colonising the slope from below.
Judging from the distribution of the tree-fern trunks, it had swallowed at
least 30 metres of grassland in less time than it takes for a tree-fern to
rot on the damp forest floor — a decade or two at most.
Why was the forest expanding? As I pondered the mouldering trunks I remembered
reading that New Guinea’s glaciers were melting. Had the temperature on Mt
Albert Edward warmed enough to permit trees to grow where previously only
grasses could take root? My doctoral studies were in palaeontology, so I
knew how important changes in climate have been in determining the fate of
species. But this was the first evidence I’d seen that it might affect Earth
during my lifetime. The experience left me troubled; I knew there was
something wrong, but not quite what it was.
For years I had resisted the impulse to devote research time to climate
change. I was busy with other things, and I wanted to wait and see, hoping
an issue so big would sort itself out. But by 2001, articles in scientific
journals indicated that the world’s alpine environments were under threat.
As I read them I remembered those rotting tree-fern trunks in Mt Albert
Edward’s forest, and I knew that I had to learn more.
THE LONG SUMMER that has been the past 8,000 years is without doubt the
crucial event in human history. It was during this period that we acquired
most of our major crops and domestic animals, the first cities came into
being, the first irrigation ditches were dug, the first words written down
and the first coins minted.
Until very recently, it was thought that this long summer resulted from a
cosmic fluke. Bill Ruddiman, an environmental scientist at the University of
Virginia, found nothing in the natural cycles that could account for the
stability of our long summer, and so he began to look for a unique factor —
something that was operating only in this last cycle, but in none of the
earlier ones.
That unique factor, he decided, was ourselves — and in doing so he
revolutionised another recent development: the endowing on our
post-industrial times of its own geological period. It was the Nobel
laureate Paul Crutzen (awarded the prize for research into the ozone hole)
and his colleagues who first recognised this momentous geological event.
They called it the Anthropocene — meaning the age of humanity — and they
marked its dawn at AD1800 when methane and CO2 brewed up by the gargantuan
machines of the Industrial Revolution first began to affect Earth’s climate.
Greenhouse gases can trap heat near Earth’s surface. As they increase in the
atmosphere, the extra heat they trap leads to global warming. This warming
in turn places pressure on Earth’s climate system, and can lead to climate
change.
Without these molecules our planet would be dead cold — a frigid sphere with
an average surface temperature of minus 20C (-4F). But we have known, and
for some time, that these gases have been accumulating. CO2 is the most
abundant of the “trace” greenhouse gases and it’s produced whenever we burn
something, or when things decompose.
In Hawaii, during the 1950s, the climatologist Charles Keeling showed that
every Northern spring there is a reduction in CO2 as sprouting greenery
extracts it for photosynthesis — and in autumn, as these shoots decompose,
there is an increase. Keeling’s work also proved that every year, each
exhalation ended with a little more CO2 in the atmosphere than the one
before.
This was the first definite sign that the great aerial ocean — the Earth’s
atmosphere — might prove to be the Achilles’ heel of our
fossil-fuel-addicted civilisation. One only needs to trace the trajectory of
this increase forward in time to realise that the 21st century would see a
doubling of CO2 in the atmosphere — from three parts per 10,000 that existed
in the early 20th century to six. That has the potential to heat our planet
by about 3C, and perhaps by as much as 6C.
Global warming changes climate in jerks, during which climate patterns jump
from one stable state to another. Because of the atmosphere’s telekinetic
nature, these changes can manifest themselves instantaneously across the
globe. The best analogy is perhaps that of a finger on a light switch.
Nothing happens for a while, but if you increase the pressure a certain
point is reached, a sudden change occurs and conditions swiftly alter from
one state to another.
The climatologist Julia Cole refers to the leaps made by climate as “magic
gates”, and she argues that since temperatures began rising rapidly in the
1970s our planet has seen two such events — in 1976 and in 1998.
Between 1945 and 1955 the temperature of the surface of the tropical Pacific
commonly dipped below 19.2C, but after the magic gate opened in 1976 it has
rarely been below 25C. “The western tropical Pacific is the warmest area in
the global ocean and is a great regulator of climate,” says Dr Martin
Hoerling, of the Climate Diagnostics Centre at Boulder, Colorado, for, among
other things, it controls most tropical precipitation and the position of
the Jet Stream (the air currents that form around areas of different
temperature), whose winds bring snow and rain to North America. In 1977
National Geographic ran a feature on the crazy weather of the previous year,
which included unprecedented mild conditions in Alaska and blizzards in the
lower 48 states. The immediate cause was a shift in the Jet Stream, but it
wasn’t just the US that was affected: changes occurred as far afield as
southern Australia and the Galapagos Islands.
Ever since Charles Darwin used the Galapagos Islands finches to illustrate his
theory of evolution by natural selection the region has been a mecca for
biologists. Scientists studying the native finch Geospiza fortis watched
helplessly as the 1977 drought all but exterminated the species on one of
the islands. Of the population of 1,300 that existed before the drought,
only 180 survived, and these were all individuals with the largest beaks,
which enabled them to feed by cracking tough seeds. Of those 180 survivors,
150 were males, so when the rains finally came the male finches found
themselves facing tough competition for mates. Again, it was those with the
biggest beaks that won. With this double whammy of natural selection sieving
out all except those with the very largest beaks, a measurable shift in the
beak size occurred on the island population. Darwin’s finches are largely
defined on the basis of their beak size, for they divide up the islands’
ecological niches according to what they can eat, and with nearly two
centuries’ worth of beak measurements to examine biologists felt they were
witnessing the evolution of a new species.
The 1998 magic gate is also tied up with the El Niño/La Niña cycle, a
two-to-eight-year-long cycle that brings extreme climatic events to much of
the world. The 1997-98 El Niño year has been immortalised by the World Wide
Fund for Nature as “the year the world caught fire”.
Drought had a stranglehold on a large part of the planet, and so fires burnt
on every continent, but it was in the normally wet rainforests of South-East
Asia that the conflagrations reached their peak. There, more than ten
million hectares were burnt, of which half was ancient rainforest. On Borneo
five million hectares were lost — an area almost the size of the
Netherlands.
The idea that severe El Niño events can permanently alter global climate was
first published in 1996, but was considered highly speculative. That 1998
event changed that, for it released enough heat energy to spike the global
temperature by around 0.3C. The 1997-98 El Niño ravaged the nations
bordering the southwest Pacific.
The region lying east of Wallace’s Line (marking the divide between the
Oriental and Australian zoogeographic regions) and centred on Australia is
known as Meganesia, and it has an ancient and distinctive flora and fauna.
The richest habitat in all of Meganesia is the montane oak forests of New
Guinea, and they reach their finest development between 1,500 and 2,000
metres elevation in valleys draining north from the watershed in the centre
of the island. There, during the oak-fruiting season, the rich humus of the
forest floor is littered with large, shiny brown acorns. If you pick one up,
you’ll most likely find that it has been chewed, for these forests are home
to more species of possum and giant rat than anywhere on earth, and many of
them love nothing more than to snack on acorns.
When I first saw these wondrous forests in the Nong River valley in 1985 they
stretched before me into the blue distance, an unbroken, primeval
wilderness. The Nong isn’t the easiest place in the world to reach, so when
the opportunity to return came up in 2001, I jumped at it. You might imagine
how excited I was, but even before the helicopter landed my spirits had
plummeted. The entire valley, along with the surrounding peaks, had been
transformed into a vast grove of vegetable tombstones.
© Tim Flannery 2006 Extracted from The Weather Makers, to be
published by Allen Lane on March 2 at £20 (www.penguin.co.uk) Available for
£18 from Times Books First, 0870 1608080, www.timesonline.co.uk/booksfirstbuy
MEET THE AUTHOR
How Climate Change Shapes Our World
A discussion at St Paul’s Cathedral between Tim Flannery, David Attenborough
and Claire Foster, policy adviser to the Church of England on science,
medicine, technology and environmental issues
March 6, 2006, 6.30-8pm. Admission free.
Visit www.timesonline.co.uk/weathermakers to obtain free tickets. Doors open
at 5.50pm.
