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Global warming - the defining
challenge of the 21st century.

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According to some, it's the greatest
threat now facing the human race.

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By the middle of the next century,
the warming will be on a level which

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the earth has not experienced
since the age of the dinosaurs.

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But for more than 20 years,
a group of scientists have

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passionately argued that
there IS no climate crisis.

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There is no scientific evidence
that greenhouse warming

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is occurring, or if it is,
that it would lead to disaster.

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They are the
climate change sceptics,

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and they've turned global warming

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into the most hotly-debated issue
that science has ever seen.

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It was a debate in which
hard science was mixed with vitriol

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and personal abuse on both sides.

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This was deliberately bent.

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It's a scandal.
If it's fraud, they should be in jail.

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The sceptics challenged
everything about global warming,

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that it was manmade,
that carbon dioxide was causing it,

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even that it was happening at all.

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Everything that we thought of
as solid fact

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was called into question.

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I'm lain Stewart, a geologist
at the University of Plymouth,

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and I'm going to look at how
the arguments over global warming

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were fought over
the last two decades...

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who won, who lost.

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This is a debate
that matters to all of us.

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Our future depends on it.

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This was science's great
battle for the truth.

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In the early '90s
it seemed so clear -

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scientists had revealed that
the planet faced a new threat.

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They said the earth was heating up.

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This evidence represents
very strong case that

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the greenhouse effect
has been detected
and it is changing our climate now.

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The culprit was emissions of carbon
dioxide and other greenhouse gases -

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the result of human activity.

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Without drastic action to curb
these gases, they said,

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the planet
would face a climate crisis.

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If measures are not undertaken
soon to limit the warming,

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humans face
an increasingly difficult future.

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The challenge was great,

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but at least the world was united.

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In 1992 almost every head of state
and an entire army of reporters

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descended on Rio
for the Earth Summit.

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The spirit of Rio
that is the spirit of planet Earth

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will spread throughout the world.

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All the countries are expected to
sign the climate change convention.

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We come to press on with deliberate
purpose and forceful action,

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and such action will demonstrate our
continuing commitment to leadership

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and to international cooperation
on the environment.

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I remember the Rio summit cos
I remember my geography colleagues

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getting all excited
about the world becoming united

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in its concern for the environment.

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And global warming was centre stage.

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Everyone was talking about what
it would mean, how to prevent it,

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even some people that you
wouldn't actually think of

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as being arch environmentalists.

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But then
the consensus started to break up.

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Politicians, businessmen
and even a few scientists

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began to queue up to say there
was no climate crisis, after all.

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A few of them are still saying that.

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This is a gathering of the world's
most vocal global warming sceptics.

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At this conference,
there are scientists,

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but also economists, philosophers,
politicians and campaigners.

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Even a stand-up comedian.

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Thank you. Thank you, all.
I think it's ironic

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that we even
have to have this conference

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in the middle of the coldest winter
in 40 years.

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I mean, couldn't global warming
be a good thing?

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You know, I think New York might be
pretty with a palm tree or two.

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What's it like being
a climate change comedian?

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Lonely!

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'But this conference
has a serious purpose,

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'to question the idea
that we're facing a climate crisis. '

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Global warming is not a crisis.

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This conference
proved there's no consensus.

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CO2 is in no way connected
to global warming.

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And it never has driven temperature.
It never will.

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Schoolchildren
are being scared to death

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based on speculative,
unproven computer models,

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and a lot of people,
including the media,
should be ashamed of themselves.

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'Some of the scientists here
have spent years questioning

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'catastrophic global warming,
like climatologist Pat Michaels. '

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You seem to really thrive on
the energy of the debate of this.

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Well, sure.

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I picked up this was going to happen
somewhere around 1972.

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"I date myself," said Woody Allen.

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Have you lost friends over this,
for example,
or does it get to that level?

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No, I don't think anybody should
go into science to make friends.

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The carbon dioxide
is not a pollutant.

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Are you saying we're
now at a climate optimum?

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I do not know of a single scientist

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who accepts the fact that there's
been any increase in global warming.

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Some see these people as heroes,
as modern-day Galileos,

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speaking out
against oppressive orthodoxy.

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Others compare them to
Holocaust deniers.

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I mean, that is one hell
of a difference of opinion.

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This has been happening
since the world began.

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They're controversial
because, for two decades,

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the sceptics have been questioning
every piece of
the global warming theory.

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They've laid down
challenge after challenge

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to the proponents of climate change.

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According
to these global warming enthusiasts,

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the main villain
is the burning of fossil fuels,

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but they've left science
and scientists far behind.

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There always seems to be
an apocalypse around the corner.

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And it seemed to me
that global warming

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was just another
in a long series...

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The world is not going
to die because of carbon dioxide

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being put into the atmosphere,
and there's plenty of proof.

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They questioned the
causes of global warming.

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It's kind of a natural phenomenon.

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They questioned whether
it was anything unusual.

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England was just
as warm as it is now.

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And their first line of attack...

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.. was to question
the most basic claim of all.

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They said the world
wasn't actually getting warmer.

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It seems like
such a simple question:

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is the world getting hotter or not?

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Surely science can answer
that without too much trouble?

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And yet, how do you measure
the temperature of a planet?

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I mean,
where do you stick the thermometer?

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The answer is: everywhere.

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All over the world,
from Morocco to Montana,

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from New Zealand to Norway,

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on mountains, in deserts,

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even in people's back gardens,

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you'll find little wooden boxes.

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These unassuming things
are what all the fuss is about.

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You find a lot of them in schools.

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And here at Stonyhurst,
a Catholic college in Lancashire,

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they've got a really special one.

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And here it is. Look at that!

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I mean, on the face of it,
there's nothing special about it -

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the box keeps out the sun
and slats let the air through.

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And inside
are simple mercury thermometers.

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These two are the important ones.

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This one measures
the maximum daily temperature,

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which is about 16 degrees Celsius.

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And this one measures the minimum,

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which is about one degree Celsius.

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Now, if you take a point
exactly halfway between the two,

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you get today's average temperature.

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What makes this special
is that it's part of

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the oldest temperature record
in the world.

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They've been measuring
temperature here since 1846.

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Now, back then, this place was run
by Jesuit priests - just the kind of

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methodical, dedicated people
that you needed for a job like this.

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For over a century,
they would come out every day.

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Nowadays it's all computerised,

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but they're still taking
measurements daily,

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which means you can make
a direct comparison

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between temperatures here today
and temperatures in the past.

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For over a century,
people all around the world

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have been collecting this data.

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This is real science.

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Painstaking work by thousands
of forgotten volunteers.

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They probably never imagined just
how important their work would be,

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because when all the temperature
data was put together,

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it told a striking story.

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Starting in 1910,
according to the thermometers,

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the global temperature
started to rise.

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Records were broken.

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And broken again.

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until the 1940s.

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Then the warming paused.

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Only to start again in the '70s.

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This was the second warming phase
of the 20th century,

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and, according to the instruments,

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it was even more
dramatic than the first.

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England has been basking
in the heat wave again.

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In many parts of the country

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it's been hotter
than Hong Kong or Honolulu.

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Throughout the '80s and '90s,
almost every year broke records.

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The Met Office says the
last 12 months have been the warmest

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since their records began
in the 17th century.

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Last year the earth recorded
its highest average temperature

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since climate records began.

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In total,
the global temperature has increased

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by almost one degree Celsius
in the last century.

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That may not sound like much, but to
climatologists this is a big deal.

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The headlines were hard to ignore.

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Something was happening
to the planet.

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It was almost as if
we'd turned up the gas,

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and the earth was beginning to cook.

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But even with thousands of
weather stations round the globe,

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there were still
huge areas of the world
with hardly any temperature data.

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For the sceptics, this made the
thermometer records deeply suspect.

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Fortunately, a new technology
had arrived on the scene...

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.. satellites.

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These precision instruments
were the space-age way

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to measure
the true global temperature.

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They're really
extraordinary pieces of technology.

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I use data
from satellites all the time.

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I even teach
a little bit about satellites.

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But I've never seen one.
I've never been close to one.

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Right.

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This is NASA's latest earth
observation satellite,

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due to be launched
into space in 2010.

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Here's the baby.

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Look at it - she's beautiful!

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All right. There's a few
things you have to know about this.

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First of all,
this is pretty much how it goes up.

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Actually, some of the bits
are coated over for protection,

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so they strip that off
and they strip off some of the wire,

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but it pretty much goes up.

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There's no shields
or anything like that.

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The other thing that's odd
is it's actually upside down.

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That is space and the roof
is where the earth would be.

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Now, in terms of
your instruments, up here,

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behind this very fetching orange,
is a visible camera,

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in the sense that it records the
images just like the human eye does.

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And this one here
you've got infra red.

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Now, this, this,
this is the important one.

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This is what gives us temperature.

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This is a microwave sounding unit,

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which kind of acts like
a microwave oven, but in reverse.

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Instead of emitting microwaves,
it receives and records microwaves.

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And, depending on the amount
of microwave radiation it receives,

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that gives us
an idea about temperature.

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With global coverage
and high-tech instruments,

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satellites seemed like
a much better way

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of measuring global temperatures
than thermometers.

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put together the satellite data.

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What they found rocked
the entire global warming community.

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The satellites showed
that the earth wasn't warming -

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in fact, it was slightly cooling.

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One of the scientists who performed
the calculations was Dr Roy Spencer.

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When we first did

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the satellite monitoring
and got 10 years of data worth,

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it did show a slight cooling,
which was a surprise to us.

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This result was in stark contrast
to what other scientists
had been saying.

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The rate of warming in the past 25
years is the highest on the record.

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It was about this time that
Jim Hansen was talking about
catastrophic global warming

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or potentially
catastrophic global warming,

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and here we had
the satellites telling us

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it's been cooling for 10 years.

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It was a huge victory
for the sceptics.

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And it soon became a key piece of
evidence against global warming,

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as this documentary from 1990 shows.

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New data from space has made
the land record more doubtful.

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Until recently, we've had
no alternative but to rely on
thermometers and weather balloons,

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but now, for the first time,

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satellites are giving us
another source of information.

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00:16:01,600 --> 00:16:06,120
We've found we can monitor globally
averaged atmospheric temperatures

244
00:16:06,155 --> 00:16:09,325
with a high level of precision,
even on a monthly basis.

245
00:16:09,360 --> 00:16:14,640
Over the last 10 years
the thermometer record has shown
an underlying upward trend.

246
00:16:14,675 --> 00:16:17,005
But according to
the satellite information

247
00:16:17,040 --> 00:16:19,920
the earth was rather warmer
in the first half of the '80s

248
00:16:19,955 --> 00:16:21,840
and rather cooler
in the second half.

249
00:16:24,800 --> 00:16:27,365
Wow! Well, that's
a pretty striking difference.

250
00:16:27,400 --> 00:16:31,360
I mean, you could see why
the climate sceptics were delighted

251
00:16:31,395 --> 00:16:33,525
when they got hold of
this satellite data

252
00:16:33,560 --> 00:16:37,760
because you've got the red lines
showing the thermometer data,

253
00:16:37,795 --> 00:16:39,525
and it's clearly going up.

254
00:16:39,560 --> 00:16:42,840
And then you've got the blue line
showing the satellite data

255
00:16:42,875 --> 00:16:46,045
with no sign of warming at all.

256
00:16:46,080 --> 00:16:48,965
The question is,
which one of those is right?

257
00:16:49,000 --> 00:16:53,320
It is the humble thermometer
or is it the high-tech satellite?

258
00:16:53,355 --> 00:16:56,577
It's a classic scientific problem.

259
00:16:56,612 --> 00:16:59,666
You've got two
different sets of data

260
00:16:59,701 --> 00:17:02,390
which are saying conflicting things.

261
00:17:02,425 --> 00:17:05,012
And the one thing
that science tells us

262
00:17:05,047 --> 00:17:07,565
is that
there's going to be a showdown.

263
00:17:07,600 --> 00:17:10,760
And only one set of data
is going to be left standing.

264
00:17:12,360 --> 00:17:14,965
First on the attack
were the sceptics.

265
00:17:15,000 --> 00:17:20,120
They said there was one
very obvious flaw in the data
from the thermometers -

266
00:17:20,155 --> 00:17:23,880
they had ignored human progress.

267
00:17:36,320 --> 00:17:38,920
Welcome to Las Vegas.

268
00:17:44,200 --> 00:17:45,885
Las Vegas.

269
00:17:45,920 --> 00:17:50,880
Like it or not, it's one of the 20th
century's greatest achievements.

270
00:17:52,120 --> 00:17:53,680
They don't do that in Glasgow.

271
00:17:57,800 --> 00:18:01,200
And this is where
Britney got married -

272
00:18:01,235 --> 00:18:02,840
for 55 hours.

273
00:18:04,360 --> 00:18:07,845
This is the perfect place
to test out a phenomenon which

274
00:18:07,880 --> 00:18:12,440
became central to the sceptic's
case against the thermometer record.

275
00:18:15,680 --> 00:18:17,960
The thing is
I'm not really here to have fun.

276
00:18:17,995 --> 00:18:20,377
I'm actually here
to measure temperature,

277
00:18:20,412 --> 00:18:22,725
which,
according to this thermometer,

278
00:18:22,760 --> 00:18:26,120
even though it's late at night,
is 22 degrees Celsius,

279
00:18:26,155 --> 00:18:27,885
which is pretty warm.

280
00:18:27,920 --> 00:18:31,560
It's Vegas, baby! So it's hot?
It's hot all the time!

281
00:18:34,880 --> 00:18:38,620
But the significant thing is,
drive out of the city

282
00:18:38,655 --> 00:18:42,360
and into the desert proper,
and the temperature drops.

283
00:18:53,000 --> 00:18:56,240
Well, now we're... um...
I don't know where we are actually,

284
00:18:56,275 --> 00:18:59,120
in the middle of nowhere,
but outside the city limits,

285
00:18:59,155 --> 00:19:00,925
and my thermometer is reading...

286
00:19:00,960 --> 00:19:03,540
Well, it's reading
about 18 degrees C,

287
00:19:03,575 --> 00:19:06,085
so, much cooler
than it was in there.

288
00:19:06,120 --> 00:19:11,240
And the reason's simple; all that
concrete, all those roads and cars,

289
00:19:11,275 --> 00:19:13,925
all the stuff you get
in modern cities,

290
00:19:13,960 --> 00:19:18,120
absorb the heat of the day
and then they release it at night.

291
00:19:18,155 --> 00:19:19,525
And those tall buildings,

292
00:19:19,560 --> 00:19:23,245
they trap the warm air
that would otherwise blow away.

293
00:19:23,280 --> 00:19:27,520
It's the same story all over
the world - cities are heat traps.

294
00:19:31,680 --> 00:19:35,240
It's called
the Urban Heat Island Effect.

295
00:19:36,561 --> 00:19:38,967
And that effect,
said the sceptics,

296
00:19:38,967 --> 00:19:43,440
had created the false impression
of a warming planet.

297
00:19:51,080 --> 00:19:54,405
Take what happened to
the Las Vegas weather station.

298
00:19:54,440 --> 00:20:00,200
It was built in 1942 out in the
desert, next to the local airstrip.

299
00:20:02,120 --> 00:20:05,160
But then Las Vegas grew.

300
00:20:06,160 --> 00:20:09,605
It's America's fastest growing city.

301
00:20:09,640 --> 00:20:14,040
Its population has tripled
in just 30 years.

302
00:20:19,880 --> 00:20:22,205
The weather station's
still at the airport,

303
00:20:22,240 --> 00:20:25,720
you can see it just over here,
behind this fence.

304
00:20:27,880 --> 00:20:32,040
Las Vegas airport has been
gradually swallowed up by the city.

305
00:20:32,075 --> 00:20:36,200
Over the back there, you can see
the famous Las Vegas strip.

306
00:20:38,920 --> 00:20:42,445
So we are in the middle of the city,

307
00:20:42,480 --> 00:20:46,520
and that means we're in the middle
of the urban heat island.

308
00:20:46,555 --> 00:20:50,560
And that means it's much hotter
here than it would be naturally.

309
00:20:50,595 --> 00:20:54,437
Sure enough,
this weather station has shown

310
00:20:54,472 --> 00:20:58,280
a four-degree warming
over the past 50 years,

311
00:20:58,315 --> 00:21:01,245
whereas a nearby desert station

312
00:21:01,280 --> 00:21:03,400
shows a warming of
less than one degree.

313
00:21:06,160 --> 00:21:08,445
So the sceptics said, "Yes, sure.

314
00:21:08,480 --> 00:21:10,980
"All around the world
the weather stations

315
00:21:11,015 --> 00:21:13,445
"are recording
ever-increasing temperatures.

316
00:21:13,480 --> 00:21:16,800
"But that's because of
the growth of cities. The planet?

317
00:21:16,835 --> 00:21:18,720
"That's not getting warmer at all. "

318
00:21:21,200 --> 00:21:25,880
If they were right, the thermometer
record was indeed faulty,

319
00:21:25,915 --> 00:21:28,717
and global warming
was a false alarm.

320
00:21:28,752 --> 00:21:31,485
But there was a counter argument -

321
00:21:31,520 --> 00:21:34,480
it wasn't only cities
that were heating up.

322
00:21:36,600 --> 00:21:40,560
All across the globe, there was
evidence that the world was warming.

323
00:21:43,280 --> 00:21:46,045
In the countryside,

324
00:21:46,080 --> 00:21:48,765
spring was coming earlier.

325
00:21:48,800 --> 00:21:51,680
In the mountains,
glaciers were retreating

326
00:21:51,715 --> 00:21:55,320
further than they had for centuries.

327
00:21:56,680 --> 00:22:00,160
So much so that all sorts of
things were melting out of the ice,

328
00:22:00,195 --> 00:22:04,840
including a human body
frozen 5,000 years before.

329
00:22:06,080 --> 00:22:08,240
Oetzi the iceman.

330
00:22:09,840 --> 00:22:12,445
Even the oceans were warming -

331
00:22:12,480 --> 00:22:15,365
not a lot of urban
development there.

332
00:22:15,400 --> 00:22:19,040
All these things seemed
to back up the thermometer record,

333
00:22:19,075 --> 00:22:20,600
not the satellites.

334
00:22:23,800 --> 00:22:28,120
It was deadlock -
one side had to be wrong,

335
00:22:28,155 --> 00:22:30,640
but it wasn't clear which one.

336
00:22:36,520 --> 00:22:40,640
Finally, after almost 10 years
of pouring over the data,

337
00:22:40,675 --> 00:22:43,641
someone did find a fault.

338
00:22:44,090 --> 00:22:46,320
And it was with the data
from the satellites.

339
00:22:48,640 --> 00:22:52,240
The problem
turned out to be friction.

340
00:22:52,275 --> 00:22:55,925
Even at 800km, the satellites

341
00:22:55,960 --> 00:22:58,480
were still affected by
the earth's atmosphere.

342
00:23:00,840 --> 00:23:02,845
That made them slow down.

343
00:23:02,880 --> 00:23:08,240
So every year they fell
about 1km closer to the earth.

344
00:23:08,275 --> 00:23:10,045
To work out the temperature

345
00:23:10,080 --> 00:23:12,805
they needed to take
into account the height,

346
00:23:12,840 --> 00:23:17,925
so having the wrong height meant
the temperature was wrong, too.

347
00:23:17,960 --> 00:23:22,920
To make matters worse, the drag also
affected the satellite's timing.

348
00:23:22,955 --> 00:23:24,725
Take a satellite which started off

349
00:23:24,760 --> 00:23:27,840
measuring the temperature
at 2:00 in the afternoon.

350
00:23:27,875 --> 00:23:31,845
After a few years, it was
measuring at 6:00 in the evening.

351
00:23:31,880 --> 00:23:36,049
So it looked like the temperature
had cooled, when it hadn't.

352
00:23:36,736 --> 00:23:39,480
Once this was pointed out,
even the scientists

353
00:23:39,515 --> 00:23:43,880
behind the original calculations
admitted they were wrong.

354
00:23:45,040 --> 00:23:46,645
I think it is a bit embarrassing

355
00:23:46,680 --> 00:23:50,040
for scientists when someone shows
they're wrong on something.

356
00:23:50,075 --> 00:23:52,005
So yes, it is a little embarrassing

357
00:23:52,040 --> 00:23:54,320
when somebody
finds an error in your data.

358
00:23:54,355 --> 00:23:56,537
Oh, I mean,
you've got to feel for them.

359
00:23:56,572 --> 00:23:58,685
I mean,
I would be absolutely mortified

360
00:23:58,720 --> 00:24:02,640
if I had to admit
a high profile mistake like that.

361
00:24:02,675 --> 00:24:04,737
For me, the important thing is that

362
00:24:04,772 --> 00:24:06,765
Spencer admitted
he'd made a mistake.

363
00:24:06,800 --> 00:24:10,280
When the error was pointed out
to him he redid his calculations

364
00:24:10,315 --> 00:24:13,760
and right enough he came up
with a rather different answer.

365
00:24:13,795 --> 00:24:15,840
I think when we
made that correction,

366
00:24:15,875 --> 00:24:17,565
if I'm remembering correctly,

367
00:24:17,600 --> 00:24:21,360
I think we went from a cooling trend
to a slight warming trend.

368
00:24:21,395 --> 00:24:24,160
And then, ever since then,
it's been a warming trend,

369
00:24:24,195 --> 00:24:27,560
- actually by sort of
ever-increasing amounts.

370
00:24:28,680 --> 00:24:33,400
'Now, even die-hard sceptics had to
accept that there had been warming

371
00:24:33,435 --> 00:24:35,525
'in the second half
of the 20th century. '

372
00:24:35,560 --> 00:24:41,120
Yeah, when somebody says there's no
such thing as warming, I squirm, yes.

373
00:24:41,155 --> 00:24:45,440
Yeah. It's hard to look at all
those records and entertain that.

374
00:24:45,475 --> 00:24:48,157
How can you argue with thermometers?

375
00:24:48,192 --> 00:24:50,840
Yeah.
I don't argue with thermometers.

376
00:24:56,400 --> 00:24:59,605
The rising temperature
was now a fact,

377
00:24:59,640 --> 00:25:02,685
with thermometers
AND satellites confirming it.

378
00:25:02,720 --> 00:25:08,040
The sceptics' challenge
had actually made the case stronger.

379
00:25:08,075 --> 00:25:10,680
But the battle was far from over.

380
00:25:15,040 --> 00:25:18,400
The sceptics hit back
with a crucial question:

381
00:25:18,435 --> 00:25:22,280
was the warming man-made or natural?

382
00:25:24,680 --> 00:25:28,440
If it was natural, there was no
reason to think it would continue,

383
00:25:28,475 --> 00:25:32,480
and nothing we could do about it,
in any case.

384
00:25:32,515 --> 00:25:35,000
And the sceptics said
they had evidence

385
00:25:35,035 --> 00:25:39,005
that it WAS just natural variation,

386
00:25:39,040 --> 00:25:42,040
because they said
it had happened before.

387
00:25:42,075 --> 00:25:45,040
And the proof
could be found in history...

388
00:25:48,320 --> 00:25:52,045
In 1,000 AD, the Viking Erik the Red

389
00:25:52,080 --> 00:25:54,440
was banished from his native land
for murder.

390
00:25:55,600 --> 00:25:59,600
He landed on this coast
and made it his home.

391
00:26:01,000 --> 00:26:03,440
And he gave it a surprising name...

392
00:26:07,320 --> 00:26:10,405
Quite how this
rather bleak landscape

393
00:26:10,440 --> 00:26:13,580
came to be known as Greenland
is still debated.

394
00:26:13,615 --> 00:26:16,720
Some say it was a masterful
piece of spin by Erik,

395
00:26:16,755 --> 00:26:20,885
designed to entice settlers
to his new home.

396
00:26:20,920 --> 00:26:24,760
Others said that it may have
been more truthful than it seems.

397
00:26:24,795 --> 00:26:28,640
They argue that, back then,
Greenland was warmer

398
00:26:28,675 --> 00:26:31,657
and more hospitable
than it is today,

399
00:26:31,692 --> 00:26:34,640
a genuinely green and fertile land.

400
00:26:37,880 --> 00:26:41,005
What's certain is that
he WAS able to survive here.

401
00:26:41,040 --> 00:26:47,240
On this now barren land, the Vikings
grew crops and farmed cattle.

402
00:26:48,800 --> 00:26:51,085
This, said the sceptics,

403
00:26:51,120 --> 00:26:54,680
was proof that Greenland
was warmer 1,000 years ago.

404
00:26:58,240 --> 00:27:01,480
And this warmth
was also felt closer to home.

405
00:27:06,760 --> 00:27:09,445
According to English
historical records,

406
00:27:09,480 --> 00:27:14,365
the centuries around 1,000AD
were warm and favourable.

407
00:27:14,400 --> 00:27:19,680
Harvests were good, the population
grew and culture flourished.

408
00:27:19,715 --> 00:27:25,497
This was when Westminster Abbey
and Salisbury Cathedral were built.

409
00:27:25,532 --> 00:27:31,280
And, just like today, it was warm
enough to grow grapes in England.

410
00:27:31,315 --> 00:27:37,240
Scientists gave this period a name -
the Medieval Warm Period.

411
00:27:44,960 --> 00:27:48,965
To the sceptics,
the Medieval Warm Period

412
00:27:49,000 --> 00:27:52,200
showed that today's temperatures
are not unusual.

413
00:27:53,760 --> 00:27:55,805
It just doesn't make sense,

414
00:27:55,840 --> 00:27:58,285
if you know anything
about climate history

415
00:27:58,320 --> 00:28:02,000
and how much warmer it was
in Viking times, for example.

416
00:28:02,035 --> 00:28:05,137
All the evidence shows
that medieval warming

417
00:28:05,172 --> 00:28:08,205
was a great deal warmer
than it is today.

418
00:28:08,240 --> 00:28:11,360
So there's nothing unusual
about the current warming.

419
00:28:13,640 --> 00:28:17,525
If the medieval warm period
really was hotter than today,

420
00:28:17,560 --> 00:28:22,200
as the sceptics said, it would
support the idea that global warming

421
00:28:22,235 --> 00:28:25,280
is just part
of the climate's natural cycle.

422
00:28:28,680 --> 00:28:32,760
The historical evidence
seemed to back up the claim.

423
00:28:32,795 --> 00:28:36,525
But what scientists
needed was hard data.

424
00:28:36,560 --> 00:28:39,720
They needed to know
what the temperature really was

425
00:28:39,755 --> 00:28:42,400
1,000 years ago
in the Medieval Warm Period.

426
00:28:49,960 --> 00:28:56,360
In the 1990s, a scientist called
Michael Mann took on the task.

427
00:28:56,395 --> 00:28:59,440
But he faced a major challenge.

428
00:29:01,320 --> 00:29:04,405
It's not easy.
We have instrumental records

429
00:29:04,440 --> 00:29:10,080
on a widespread global basis, really
for only, at most, the past century.

430
00:29:10,115 --> 00:29:12,965
Then, maybe back
into the mid-19th century,

431
00:29:13,000 --> 00:29:16,805
enough instrumental
data to say something, for example,

432
00:29:16,840 --> 00:29:21,480
about the average temperature of the
Northern Hemisphere. But by the time

433
00:29:21,515 --> 00:29:25,240
you go farther back, there are
very few instrumental records.

434
00:29:32,960 --> 00:29:36,760
With no thermometer records, Michael
Mann needed something

435
00:29:36,795 --> 00:29:39,400
that could act like a natural
thermometer -

436
00:29:39,435 --> 00:29:43,925
going back centuries.

437
00:29:43,960 --> 00:29:45,800
And this is where he found it.

438
00:29:51,160 --> 00:29:54,365
I'm in the White Mountains
in California

439
00:29:54,400 --> 00:29:59,360
and this area is a real mecca for
scientists studying past climate.

440
00:29:59,395 --> 00:30:03,365
That's because
this is no ordinary forest.

441
00:30:03,400 --> 00:30:07,680
It's home to the oldest
living things on the planet.

442
00:30:09,280 --> 00:30:12,200
These trees live
for thousands of years.

443
00:30:12,235 --> 00:30:14,085
They're called Bristle Cone Pines

444
00:30:14,120 --> 00:30:17,320
and they're found only in a few
small areas of the western USA.

445
00:30:27,760 --> 00:30:30,805
This is strangely wonderful.

446
00:30:30,840 --> 00:30:33,320
It feels as if
it's oozing out everywhere.

447
00:30:35,120 --> 00:30:38,160
Mind you, it's a bit of a surprise,
considering how old it is.

448
00:30:38,195 --> 00:30:40,525
You'd think it was much bigger.

449
00:30:40,560 --> 00:30:42,565
I guess it shows
its age in other ways.

450
00:30:42,600 --> 00:30:47,200
I mean, look at this
weather-beaten and gnarled texture.

451
00:30:47,235 --> 00:30:50,557
I'm told that this one is about
2,000 years old.

452
00:30:50,592 --> 00:30:53,845
But some of the trees
are about 4,000 years old.

453
00:30:53,880 --> 00:30:58,720
When they were saplings, my
ancestors were living in straw huts.

454
00:30:58,755 --> 00:31:01,920
Stonehenge was modern architecture.

455
00:31:01,955 --> 00:31:05,320
It really stretches your mind.

456
00:31:09,840 --> 00:31:14,920
These were just what Michael Mann
was looking for, because inside,

457
00:31:14,955 --> 00:31:17,680
they contain a record
of past temperatures.

458
00:31:21,840 --> 00:31:23,845
Like any tree,

459
00:31:23,880 --> 00:31:28,040
these pines lay down rings -
one for each year of their life.

460
00:31:28,075 --> 00:31:31,325
These rings are the key
to past climate.

461
00:31:31,360 --> 00:31:34,240
This is a slice from one
of the trees. Take a look.

462
00:31:34,275 --> 00:31:37,525
You can barely see the tree rings.

463
00:31:37,560 --> 00:31:41,320
They're in there, all right -
they're just really tightly packed.

464
00:31:41,355 --> 00:31:44,045
And the reason
that each ring is so fine

465
00:31:44,080 --> 00:31:47,520
is because the tree grows
a tiny amount every year.

466
00:31:47,555 --> 00:31:51,005
That is 100 years.

467
00:31:51,040 --> 00:31:54,940
And it's these rings that
tell us about past temperatures,

468
00:31:54,975 --> 00:31:58,840
because they tell us how much
the tree grew in that year.

469
00:32:01,520 --> 00:32:05,520
In a warm year, the snows will melt
earlier and the trees will grow more

470
00:32:05,555 --> 00:32:08,245
and leave a fatter ring.

471
00:32:08,280 --> 00:32:11,280
In a cold year,
they'll hardly grow at all.

472
00:32:13,920 --> 00:32:15,925
It's called a climate proxy.

473
00:32:15,960 --> 00:32:19,760
You can't read temperatures
directly like reading a thermometer,

474
00:32:19,795 --> 00:32:23,560
but you can use the evidence to
estimate what the temperature was.

475
00:32:25,000 --> 00:32:27,920
But, of course, this only
tells you about the conditions

476
00:32:27,955 --> 00:32:29,765
in this one place.

477
00:32:29,800 --> 00:32:34,640
So Michael Mann and his team needed
to find other temperature proxies

478
00:32:34,675 --> 00:32:38,565
from all round the world - places
that could tell them

479
00:32:38,600 --> 00:32:43,880
what the temperature really
was as far back
as the Medieval Warm Period.

480
00:32:48,520 --> 00:32:52,120
They searched the world
getting data from other proxies...

481
00:32:54,480 --> 00:32:56,960
.. Like corals from the Red Sea...

482
00:32:57,960 --> 00:33:03,400
.. And ancient layers of
snow from the mountains of Peru.

483
00:33:04,160 --> 00:33:09,560
And then they had to add in
the recent thermometer records.

484
00:33:12,360 --> 00:33:16,280
Combining the different numbers
to reconstruct global temperatures

485
00:33:16,315 --> 00:33:18,325
is a fiendishly difficult task.

486
00:33:18,360 --> 00:33:22,320
It needs the kind of statistical
analysis that makes my head hurt.

487
00:33:24,200 --> 00:33:27,400
Michael Mann put all the numbers
together and used it to create

488
00:33:27,435 --> 00:33:31,120
a very special graph.

489
00:33:34,600 --> 00:33:38,085
And here it is. It's basically
a graph of temperature

490
00:33:38,120 --> 00:33:41,160
over the last 1,000 years.
And the first thing that hits you

491
00:33:41,195 --> 00:33:44,165
is there's virtually no sign
of the Medieval Warm Period.

492
00:33:44,200 --> 00:33:47,600
I mean, the sceptics would have
a big bump in temperature just here

493
00:33:47,635 --> 00:33:49,285
when the world got warmer.

494
00:33:49,320 --> 00:33:52,125
Instead, it looks like
for at least 900 years,

495
00:33:52,160 --> 00:33:56,040
give or take a few ups and downs,
it's incredibly flat.

496
00:33:56,075 --> 00:33:59,920
It's not until you get to
the 20th century and BANG!

497
00:34:01,000 --> 00:34:04,320
Temperatures shoot up in a way
unlike anything we've seen

498
00:34:04,355 --> 00:34:06,045
for at least a millennium.

499
00:34:06,080 --> 00:34:09,720
Now, this graph tells a very
different story from the sceptics.

500
00:34:09,755 --> 00:34:13,520
They say present
temperatures are nothing special.

501
00:34:13,555 --> 00:34:16,365
This graph says the opposite.

502
00:34:16,400 --> 00:34:20,440
The simplicity of this graph
makes it a really powerful image.

503
00:34:20,475 --> 00:34:24,120
And it's even been given its
own name - the Hockey Stick.

504
00:34:27,920 --> 00:34:32,360
It became one of the most famous
and controversial graphs in science.

505
00:34:32,395 --> 00:34:35,965
It was so dramatic
that it became an icon -

506
00:34:36,000 --> 00:34:42,240
an instantly recognisable symbol
of man-made climate change.

507
00:34:42,275 --> 00:34:45,960
Al Gore even used it
in his Oscar-winning movie.

508
00:34:54,680 --> 00:34:58,720
Not surprisingly, sceptics hated it.

509
00:35:01,320 --> 00:35:03,845
They said the Hockey Stick
was a fiction

510
00:35:03,880 --> 00:35:08,080
because there was virtually no trace
of the Medieval Warm Period.

511
00:35:11,480 --> 00:35:16,280
They accused Mann of using
faulty data and dodgy statistics

512
00:35:16,315 --> 00:35:18,765
to rewrite history.

513
00:35:18,800 --> 00:35:23,920
The Hockey Stick still
provokes strong reactions today.

514
00:35:23,955 --> 00:35:26,205
What was your reaction
when you saw that?

515
00:35:26,240 --> 00:35:29,780
It's probably the most famous
graph in the world, isn't it?

516
00:35:29,815 --> 00:35:33,285
I think, "What a shame. "
What a shame a scientific scandal

517
00:35:33,320 --> 00:35:36,960
would be perpetrated on the American
public and on the United Nations.

518
00:35:36,995 --> 00:35:40,005
A scandal? It's a scandal.
This is absolutely outrageous!

519
00:35:40,040 --> 00:35:43,565
This has even been discredited by
the National Academy of Sciences.

520
00:35:43,600 --> 00:35:47,680
They said it was unsupportable.
When you see this,
what goes through your mind?

521
00:35:47,715 --> 00:35:50,417
The first thing is
that I have great disbelief.

522
00:35:50,452 --> 00:35:53,085
Scientists are always
bitching about each other.

523
00:35:53,120 --> 00:35:57,760
I've been at a conference where
someone has said, "You know nothing
about this subject. "

524
00:35:57,795 --> 00:36:00,120
But the kind
of enmity that's been directed

525
00:36:00,155 --> 00:36:02,120
at Michael Mann is something else.

526
00:36:04,080 --> 00:36:08,000
Some even accused him of the
ultimate scientific crime - fraud.

527
00:36:09,720 --> 00:36:12,845
If it's fraud,
they should be in jail.

528
00:36:12,880 --> 00:36:17,285
If it was in confidence,
they should be fired.

529
00:36:17,320 --> 00:36:20,880
I never expected the sort of attacks
we were subject to

530
00:36:20,915 --> 00:36:22,445
when I began this work.

531
00:36:22,480 --> 00:36:26,840
This was clearly - and I'm going to
say it bluntly - deliberately bent.

532
00:36:26,875 --> 00:36:31,517
If you can't win your argument
based on science,

533
00:36:31,552 --> 00:36:36,125
you try to win based on defamation,
of slander,

534
00:36:36,160 --> 00:36:41,520
of rhetoric that sounds convincing,
but has no basis in fact.

535
00:36:41,555 --> 00:36:46,880
I would say it's as close to
scientific fraud as you can get.

536
00:36:48,400 --> 00:36:54,040
Michael Mann was attacked in print,
and even more viciously on the web.

537
00:36:54,075 --> 00:36:58,880
Entire websites were set up
to pick holes in the Hockey Stick.

538
00:37:02,960 --> 00:37:07,400
But whilst the sceptics were busy
attacking Mann, other researchers

539
00:37:07,435 --> 00:37:12,857
were doing their own science:
hunting for more proxies

540
00:37:12,892 --> 00:37:18,280
and using different methods to work
out past temperatures.

541
00:37:18,315 --> 00:37:24,377
Soon, Michael Mann's
graph was joined by many others,

542
00:37:24,412 --> 00:37:30,440
all reconstructing the past
1,000 years of temperature.

543
00:37:32,080 --> 00:37:33,605
The question was

544
00:37:33,640 --> 00:37:38,525
would they back up Michael Mann,
or would they prove him wrong?

545
00:37:38,560 --> 00:37:43,320
It might look confusing, but this
graph has a really clear message -

546
00:37:43,355 --> 00:37:47,680
the red line is Michael Mann's
original Hockey Stick graph.

547
00:37:47,715 --> 00:37:52,000
It's very flat, with hardly
any Medieval Warm Period.

548
00:37:52,035 --> 00:37:54,240
The other lines are
the reconstructions

549
00:37:54,275 --> 00:37:55,717
that have been done since.

550
00:37:55,752 --> 00:37:57,125
Now, there's a big spread.

551
00:37:57,160 --> 00:38:01,080
In other words,
scientists disagree about
a lot of the temperatures here.

552
00:38:01,115 --> 00:38:04,680
That's not really surprising,
because working out the temperatures

553
00:38:04,715 --> 00:38:08,320
for the past few hundred years
is a really difficult task.

554
00:38:08,355 --> 00:38:11,400
It largely depends
on what indications you use.

555
00:38:11,435 --> 00:38:13,440
But the crucial part is over here.

556
00:38:13,475 --> 00:38:15,965
This is 1000 AD.

557
00:38:16,000 --> 00:38:20,320
Now, some of the reconstructions
show temperatures a little warmer

558
00:38:20,355 --> 00:38:23,365
than Mann's curve,
and some of them also show

559
00:38:23,400 --> 00:38:28,520
going into much colder conditions at
the end of the Medieval Warm Period.

560
00:38:28,555 --> 00:38:32,720
What that probably means
is that Michael Mann underestimated

561
00:38:32,755 --> 00:38:36,845
some of the variation
in the past 1,000 years.

562
00:38:36,880 --> 00:38:40,120
In other words, the Hockey Stick
is a little bit too straight,

563
00:38:40,155 --> 00:38:43,525
but it depends
on the reconstruction you use.

564
00:38:43,560 --> 00:38:47,600
What these lines all agree on,
though, is one thing -

565
00:38:47,635 --> 00:38:51,277
there's no evidence of any
period in the past 1,000 years

566
00:38:51,312 --> 00:38:54,885
that's as warm as the second
half of the 20th century.

567
00:38:54,920 --> 00:39:00,400
In other words, the end of the 20th
century really is unprecedented.

568
00:39:02,560 --> 00:39:07,280
Once again, the sceptical attacks
have made the science stronger.

569
00:39:07,315 --> 00:39:11,525
We now have a whole
hockey team's worth of graphs.

570
00:39:11,560 --> 00:39:16,725
They make a very convincing case
that the global warming

571
00:39:16,760 --> 00:39:22,440
detected by the thermometers
and satellites really is unusual.

572
00:39:22,475 --> 00:39:26,085
But the sceptics said
that still doesn't prove

573
00:39:26,120 --> 00:39:31,640
that humans are to blame. They had
one more line of scientific attack.

574
00:39:31,675 --> 00:39:36,560
They said global warming has
nothing to do with carbon dioxide,

575
00:39:36,595 --> 00:39:41,040
so leave those smokestacks
and gas guzzlers alone.

576
00:39:41,075 --> 00:39:45,040
It was all the fault of the sun.

577
00:39:55,320 --> 00:39:58,360
Of course
the sun influences climate -

578
00:39:58,395 --> 00:40:01,400
the sun is the source
of all weather.

579
00:40:05,160 --> 00:40:10,480
Every storm, every shower,
every breath of wind,

580
00:40:10,515 --> 00:40:13,200
is ultimately driven by the sun.

581
00:40:15,280 --> 00:40:20,080
The sceptics argued that since
the Earth's climate is so dependent

582
00:40:20,115 --> 00:40:24,880
on the sun, it would only take small
changes in the sun's behaviour

583
00:40:24,915 --> 00:40:27,720
to have a big effect
on the climate.

584
00:40:36,280 --> 00:40:40,005
The key was sunspots.

585
00:40:40,040 --> 00:40:45,160
These dark patches are magnetic
storms on the surface of the sun.

586
00:40:45,195 --> 00:40:48,565
They're constantly changing,

587
00:40:48,600 --> 00:40:53,240
which is why the sceptics believed
they could reveal the true cause

588
00:40:53,275 --> 00:40:55,400
of climate change.

589
00:41:07,040 --> 00:41:10,440
This observatory has been
measuring sunspots since 1881.

590
00:41:10,475 --> 00:41:11,765
And this is how they do it -

591
00:41:11,800 --> 00:41:15,000
the dome moves around until it gets
to the direction of the sun,

592
00:41:15,035 --> 00:41:18,200
the roof opens, and then the sun
comes down this telescope here

593
00:41:18,235 --> 00:41:20,245
and projects onto
this sheet of paper.

594
00:41:20,280 --> 00:41:23,280
Now, I'm not putting my head
up here, because, if I did,

595
00:41:23,315 --> 00:41:24,845
this is what would happen.

596
00:41:24,880 --> 00:41:29,120
The sun, just like a big magnifying
glass, just sets fire to the leaf.

597
00:41:31,800 --> 00:41:36,360
But anyway, listen. So what you do
is rather than put your eye there,

598
00:41:36,395 --> 00:41:38,477
you put a bit of paper there.

599
00:41:38,512 --> 00:41:40,525
Now, you have to adjust it,

600
00:41:40,560 --> 00:41:45,200
because the sun has to be sitting
right in the middle.

601
00:41:45,235 --> 00:41:46,680
Focus a little.

602
00:41:50,280 --> 00:41:52,445
You then draw on the position

603
00:41:52,480 --> 00:41:55,360
of the sun spots.
And we've got two today. OK.

604
00:41:57,360 --> 00:42:02,960
These spots may look tiny, but each
one is half the size of the Earth.

605
00:42:02,995 --> 00:42:06,040
And this is a relatively quiet sun.

606
00:42:07,680 --> 00:42:12,920
At other times, it has more spots -
sometimes dozens of them.

607
00:42:12,955 --> 00:42:16,685
This is what scientists call
an "active sun"

608
00:42:16,720 --> 00:42:21,080
and at these times, the sun sends
out huge waves of charged particles

609
00:42:21,115 --> 00:42:24,360
called the solar wind.

610
00:42:26,600 --> 00:42:29,840
For centuries,
astronomers all around the world

611
00:42:29,875 --> 00:42:32,760
have been counting
the number of sunspots.

612
00:42:32,795 --> 00:42:35,205
This record's from the mid-1830s

613
00:42:35,240 --> 00:42:38,560
and you can just see the detail
is incredible.

614
00:42:38,595 --> 00:42:41,297
Each of these plots
is a different day.

615
00:42:41,332 --> 00:42:44,000
Apparently some scientists even
went blind

616
00:42:44,035 --> 00:42:46,257
from all that staring at the sun.

617
00:42:46,292 --> 00:42:48,445
But what you really get from here

618
00:42:48,480 --> 00:42:51,480
is the dedication
and devotion to record-keeping.

619
00:42:51,515 --> 00:42:53,405
And it's from records like this

620
00:42:53,440 --> 00:42:56,280
that we've learned something
absolutely intriguing.

621
00:42:59,440 --> 00:43:04,400
Back in the 17th century,
there was a 50-year period in which

622
00:43:04,435 --> 00:43:07,120
there didn't seem
to be any sunspots at all.

623
00:43:10,000 --> 00:43:13,960
And the fascinating thing
is that this coincided

624
00:43:13,995 --> 00:43:17,920
with a particularly cold
period of history -

625
00:43:17,955 --> 00:43:20,405
the so-called Little Ice Age.

626
00:43:20,440 --> 00:43:26,360
This was the time of frost fairs,
when the river Thames froze over.

627
00:43:26,395 --> 00:43:32,080
It was also a time
of bitter winters and famines.

628
00:43:34,760 --> 00:43:38,000
So people began to wonder
if there was a connection

629
00:43:38,035 --> 00:43:40,397
between sunspots and the weather.

630
00:43:40,432 --> 00:43:42,725
For instance, William Herschel.

631
00:43:42,760 --> 00:43:46,600
The astronomer who discovered Uranus
claimed to have found a link

632
00:43:46,635 --> 00:43:50,400
between the number of sunspots
and the price of wheat.

633
00:43:50,435 --> 00:43:52,005
The more sunspots, he argued,

634
00:43:52,040 --> 00:43:55,600
the better the weather,
and the better the harvest.

635
00:43:55,635 --> 00:43:57,565
Mind you, he also thought

636
00:43:57,600 --> 00:44:02,160
that the sun was inhabited
by intelligent life-forms.

637
00:44:05,160 --> 00:44:09,760
The real problem for the theory
was that no-one could work out

638
00:44:09,795 --> 00:44:13,840
how sunspot activity could
be linked to the climate.

639
00:44:13,875 --> 00:44:17,085
The actual amount of heat
given off by the sun

640
00:44:17,120 --> 00:44:21,920
hardly changes at all, regardless
of how many sunspots there are.

641
00:44:21,955 --> 00:44:25,240
So the theory was largely forgotten.

642
00:44:28,800 --> 00:44:34,160
But in the 1990s, sunspots made a
comeback, because some people argued

643
00:44:34,195 --> 00:44:36,960
that it was the sun -
and not the carbon dioxide -

644
00:44:36,995 --> 00:44:39,160
that was the cause
of global warming.

645
00:44:39,195 --> 00:44:41,525
And they had a trump card.

646
00:44:41,560 --> 00:44:44,720
They believed
they'd solved the mystery

647
00:44:44,755 --> 00:44:47,320
of how the sun changes the climate.

648
00:44:49,160 --> 00:44:53,685
According to the new theory,
it wasn't that the sunspot activity

649
00:44:53,720 --> 00:44:58,880
made the sun hotter or colder - it
was much more complicated than that.

650
00:45:00,560 --> 00:45:05,160
It all starts far out in space,
where exploding stars,

651
00:45:05,195 --> 00:45:10,325
called supernovas,
send out powerful cosmic rays.

652
00:45:10,360 --> 00:45:13,760
The theory goes that when these
cosmic rays get to the Earth,

653
00:45:13,795 --> 00:45:18,520
they interact with the atmosphere
to create clouds.

654
00:45:20,160 --> 00:45:24,925
But when the sun
is active and has lots of spots,

655
00:45:24,960 --> 00:45:30,840
it sends out a powerful solar wind
which blows the cosmic rays away.

656
00:45:32,840 --> 00:45:37,760
So an active sun means fewer
clouds and a warmer world.

657
00:45:44,000 --> 00:45:49,405
This theory wasn't by any means
proven, but it was possible.

658
00:45:49,440 --> 00:45:54,420
And that led some sceptics to argue
that today's global warming might be

659
00:45:54,455 --> 00:45:59,400
caused by the natural fluctuations
of the sun, and not carbon dioxide.

660
00:46:04,600 --> 00:46:08,720
That was the message of a recent
high-profile television documentary.

661
00:46:08,755 --> 00:46:12,200
And as evidence,
they showed how solar activity

662
00:46:12,235 --> 00:46:17,045
and temperature seem to match up.

663
00:46:17,080 --> 00:46:22,040
Solar activity, they found,
rose sharply to around 1940,

664
00:46:22,075 --> 00:46:27,000
fell back until the 1970s and
then started to rise again.

665
00:46:29,400 --> 00:46:33,400
Well, you have to say
it's a pretty convincing connection.

666
00:46:33,435 --> 00:46:36,897
But there is one wee problem -
the graph ends in 1980.

667
00:46:36,932 --> 00:46:40,325
Now, when the documentary was
made a couple of years ago,

668
00:46:40,360 --> 00:46:44,400
they had data from the 1980s and
the 1990s, but they didn't show it.

669
00:46:44,435 --> 00:46:47,200
If extend that graph to show
that data, what you see is

670
00:46:47,235 --> 00:46:49,680
that the blue temperature curve
should rise up.

671
00:46:49,715 --> 00:46:50,725
Look - there it goes.

672
00:46:50,760 --> 00:46:55,720
It just soars off the graph, and the
red solar activity just levels off.

673
00:46:55,755 --> 00:46:57,325
In fact, since the 1990s,

674
00:46:57,360 --> 00:47:00,740
solar activity looks as if
it's been on the decline,

675
00:47:00,775 --> 00:47:04,120
which should mean
the planet has been getting cooler.

676
00:47:04,155 --> 00:47:07,605
Instead,
we've reached record temperatures.

677
00:47:07,640 --> 00:47:10,880
So it's hard to escape the thought
that although the sun

678
00:47:10,915 --> 00:47:13,640
may have played a significant role
in the past,

679
00:47:13,675 --> 00:47:16,120
it just can't explain
the present warming.

680
00:47:16,155 --> 00:47:18,725
The only convincing explanation

681
00:47:18,760 --> 00:47:22,360
is that it's down to us -
human activity.

682
00:47:26,720 --> 00:47:31,280
There are only a tiny number
of scientists who still question

683
00:47:31,315 --> 00:47:33,485
a human influence on climate,

684
00:47:33,520 --> 00:47:36,880
climate scepticism hasn't gone away.

685
00:47:39,960 --> 00:47:44,720
You'll still see websites claiming
that the Earth isn't warming up -

686
00:47:44,755 --> 00:47:49,480
that it's all down to the urban heat
island, but that's not true.

687
00:47:51,040 --> 00:47:53,405
You'll still hear
claims that there's proof

688
00:47:53,440 --> 00:47:57,760
that the Earth was hotter
during the Medieval Warm Period,

689
00:47:57,795 --> 00:47:59,800
but that's not true.

690
00:48:01,520 --> 00:48:04,680
And you'll still hear
people claiming that the sun

691
00:48:04,715 --> 00:48:08,320
somehow disproves global warming.

692
00:48:08,355 --> 00:48:10,885
But that's not true, either.

693
00:48:10,920 --> 00:48:13,480
So why is this stuff still around?

694
00:48:18,800 --> 00:48:20,285
The problem is

695
00:48:20,320 --> 00:48:24,520
there are a lot of people who don't
want global warming to be true.

696
00:48:28,080 --> 00:48:31,445
The fact is, I'm one of them -

697
00:48:31,480 --> 00:48:34,780
I wish there were
no such thing as global warming,

698
00:48:34,815 --> 00:48:38,080
because taking action to prevent
climate change

699
00:48:38,115 --> 00:48:40,085
is going to affect all our lives,

700
00:48:40,120 --> 00:48:42,520
and mean giving up
some of our freedom.

701
00:48:45,680 --> 00:48:48,580
The freedom to go anywhere,
do anything,

702
00:48:48,615 --> 00:48:51,445
to consume whatever you want,
when you want.

703
00:48:51,480 --> 00:48:57,360
The freedom to have an open road
and a car full of cheap petrol.

704
00:49:00,360 --> 00:49:03,840
# Don't tell me not to fly
I've simply got to... #

705
00:49:03,875 --> 00:49:06,445
It's not only my freedom
that's threatened -

706
00:49:06,480 --> 00:49:10,760
cutting back on greenhouse gases
threatens the freedom of companies

707
00:49:10,795 --> 00:49:13,405
to go about their business.

708
00:49:13,440 --> 00:49:15,645
#.. Don't tell me
not to live just... #

709
00:49:15,680 --> 00:49:19,125
Not surprisingly,
they wanted to fight their case.

710
00:49:19,160 --> 00:49:24,080
#.. Who told you you're allowed
to rain on my parade? #

711
00:49:27,360 --> 00:49:29,125
A new alliance was formed.

712
00:49:29,160 --> 00:49:34,240
It was a who's who of household
names - Exxon, BP, General Motors,

713
00:49:34,275 --> 00:49:36,845
Shell, Ford and many others.

714
00:49:36,880 --> 00:49:40,840
They called themselves
the Global Climate Coalition.

715
00:49:42,440 --> 00:49:44,045
Throughout the '90s,

716
00:49:44,080 --> 00:49:48,440
the Global Climate Coalition
embarked on a marketing campaign

717
00:49:48,475 --> 00:49:52,120
to convince the public
there was no need to take action.

718
00:49:54,240 --> 00:49:57,880
What do you know about the United
Nations' proposed climate treaty?

719
00:49:57,915 --> 00:50:00,405
Isn't that about global warming?

720
00:50:00,440 --> 00:50:03,960
It would force the US to
cut energy use by over 20%.

721
00:50:03,995 --> 00:50:07,480
Gasoline prices could go up
for over 50 cents a gallon.

722
00:50:07,515 --> 00:50:10,405
Heating and electricity
prices could soar.

723
00:50:10,440 --> 00:50:15,120
Higher energy costs will raise the
price of almost everything we buy.

724
00:50:17,440 --> 00:50:20,605
Industry was fighting back.

725
00:50:20,640 --> 00:50:26,480
A key part of their strategy was to
highlights doubts about the science.

726
00:50:26,515 --> 00:50:29,920
They used the media and the internet
to promote the views

727
00:50:29,955 --> 00:50:32,880
of the minority of scientists
who were sceptical.

728
00:50:37,240 --> 00:50:38,845
And the campaign received

729
00:50:38,880 --> 00:50:44,680
a huge boost with the election of
Republican President George W. Bush.

730
00:50:44,715 --> 00:50:47,640
I've got a question about global
warming. I want to know,

731
00:50:47,675 --> 00:50:48,640
what is your plan?

732
00:50:48,675 --> 00:50:50,645
Good.

733
00:50:50,680 --> 00:50:55,520
We, uh... first of all,
I... there is... uh,

734
00:50:55,555 --> 00:50:58,845
the, uh... the globe is warming.

735
00:50:58,880 --> 00:51:01,720
The fundamental debate -
is it man-made or natural?

736
00:51:03,120 --> 00:51:06,525
Bush's views on climate change
were no secret,

737
00:51:06,560 --> 00:51:11,240
but what was a secret was
the strategy the Republicans used

738
00:51:11,275 --> 00:51:14,485
to get the American public
on their side.

739
00:51:14,520 --> 00:51:21,160
That is, until a revealing
document came to light in 2003.

740
00:51:21,195 --> 00:51:24,920
Frank Luntz was a pollster
and political advisor

741
00:51:24,955 --> 00:51:27,485
with an impressive reputation.

742
00:51:27,520 --> 00:51:30,800
My name is Frank Luntz, and you've
been invited to participate

743
00:51:30,835 --> 00:51:32,245
in a people meter session.

744
00:51:32,280 --> 00:51:36,205
He'd been hired to help
Bush get re-elected.

745
00:51:36,240 --> 00:51:40,640
When an internal campaign memo
he wrote in 2002 was leaked,

746
00:51:40,675 --> 00:51:44,200
it revealed that it was the issue
of the environment

747
00:51:44,235 --> 00:51:47,080
on which Republicans
felt most vulnerable.

748
00:51:50,920 --> 00:51:53,245
Well, this is it - this is the memo.

749
00:51:53,280 --> 00:51:57,280
It's basically a policy document
on how Republican politicians

750
00:51:57,315 --> 00:52:00,640
should address questions
about the environment,

751
00:52:00,675 --> 00:52:02,165
about global warming,

752
00:52:02,200 --> 00:52:05,640
and there's a few really interesting
points on this.

753
00:52:05,675 --> 00:52:07,685
It says, "The scientific debate

754
00:52:07,720 --> 00:52:10,060
"is closing against us,
but not yet closed.

755
00:52:10,095 --> 00:52:12,400
"There is still
a window of opportunity

756
00:52:12,435 --> 00:52:14,045
"to challenge the science. "

757
00:52:14,080 --> 00:52:17,120
To me this says, "Look, we know
we are on the losing side now,

758
00:52:17,155 --> 00:52:19,640
we know the science is starting
to close in on us,

759
00:52:19,675 --> 00:52:21,920
"but there's still a window
of opportunity

760
00:52:21,955 --> 00:52:23,285
"to get our point across,"

761
00:52:23,320 --> 00:52:26,920
not to say, "All right, guys.
We accept there's a good chance

762
00:52:26,955 --> 00:52:28,997
"that global warming is happening.

763
00:52:29,032 --> 00:52:31,005
"We're going to change our mind.

764
00:52:31,040 --> 00:52:33,940
"We're going to change
our approach. "

765
00:52:33,975 --> 00:52:36,840
No.
I mean, look at that raw cynicism.

766
00:52:36,875 --> 00:52:38,405
Now, this is interesting.

767
00:52:38,440 --> 00:52:40,845
"The scientific
debate remains open. "

768
00:52:40,880 --> 00:52:44,805
"Should the public come to believe
that the scientific issues

769
00:52:44,840 --> 00:52:49,040
"are settled, the views about global
warming should change accordingly.

770
00:52:49,075 --> 00:52:52,357
"Therefore," - this is in bold -
"you need to continue to make

771
00:52:52,392 --> 00:52:55,640
"the lack of scientific certainty
a primary issue in the debate. "

772
00:52:55,675 --> 00:52:57,965
That's saying you need to keep
stirring it.

773
00:52:58,000 --> 00:53:01,120
Whenever there's uncertainty
or discord among science,

774
00:53:01,155 --> 00:53:02,445
you just bring that out.

775
00:53:02,480 --> 00:53:05,280
It's not about trying to resolve
the science

776
00:53:05,315 --> 00:53:06,925
to make the science better -

777
00:53:06,960 --> 00:53:09,965
it's just trying
to sow the seeds of discontent.

778
00:53:10,000 --> 00:53:13,680
There's another one here
that kind of reveals the strategy.

779
00:53:13,715 --> 00:53:17,997
"Act only with all the facts
in hand. " In other words,

780
00:53:18,032 --> 00:53:22,245
if you create that element
of scientific uncertainty,

781
00:53:22,280 --> 00:53:25,660
and you say, "We can only act
with all the facts in hand,"

782
00:53:25,695 --> 00:53:29,005
that is a recipe for inaction
cos science has never got

783
00:53:29,040 --> 00:53:32,660
all the facts in hand. It's always
looking for more information.

784
00:53:32,695 --> 00:53:36,280
This really has got nothing to do
with science - this is about

785
00:53:36,315 --> 00:53:38,317
how to skirt around the issues.

786
00:53:38,352 --> 00:53:40,285
It's very clever - I give it that -

787
00:53:40,320 --> 00:53:42,605
there's bits where you just go,
"Of course.

788
00:53:42,640 --> 00:53:47,040
"That's a very clever way to do it. "
But it's just depressing.

789
00:53:47,075 --> 00:53:49,200
We should be trying
to find out the truth.

790
00:53:52,520 --> 00:53:56,480
It's pretty obvious
that the aim of all this is to avoid

791
00:53:56,515 --> 00:53:58,965
taking action on climate change.

792
00:53:59,000 --> 00:54:03,080
As long as the public believe that
scientists disagree on the issue,

793
00:54:03,115 --> 00:54:05,360
they won't demand action.

794
00:54:10,200 --> 00:54:12,765
But as the scientific
evidence has accumulated

795
00:54:12,800 --> 00:54:18,300
in favour of global warming, it's
become harder and harder to claim

796
00:54:18,335 --> 00:54:23,800
that there's any real scientific
disagreement on the core issues.

797
00:54:23,835 --> 00:54:28,560
The science that said,
"The world is warming

798
00:54:30,640 --> 00:54:36,160
"and the world is warming as
a result of human activities,"

799
00:54:36,195 --> 00:54:38,405
is beyond any reasonable doubt.

800
00:54:38,440 --> 00:54:42,280
The Global Climate Coalition has
now disbanded,

801
00:54:42,315 --> 00:54:45,045
with many of the companies involved

802
00:54:45,080 --> 00:54:48,280
accepting the reality
of climate change.

803
00:54:50,720 --> 00:54:52,565
But there are still sceptics

804
00:54:52,600 --> 00:54:55,565
who maintain that the science
isn't settled.

805
00:54:55,600 --> 00:54:59,205
And they explain away
the mass of scientific opinion

806
00:54:59,240 --> 00:55:04,645
by claiming that the whole
global warming theory is a fraud.

807
00:55:04,680 --> 00:55:08,720
When you get the National Climate
Data Centre withholding the locations

808
00:55:08,755 --> 00:55:12,760
of its temperature stations - and
at the moment one or two of them were

809
00:55:12,795 --> 00:55:17,217
found to be in urban heat island
areas - you find the Hockey Stick

810
00:55:17,252 --> 00:55:21,640
data suppressed, hidden, not
released, until two years of bullying

811
00:55:21,675 --> 00:55:25,800
eventually made the authors part
with a messy version of it,

812
00:55:25,835 --> 00:55:28,925
then one immediately smells a rat.

813
00:55:28,960 --> 00:55:32,365
It's quite simple.
If you can see serial,

814
00:55:32,400 --> 00:55:35,940
deliberate falsifications of
data, withholding of data,

815
00:55:35,975 --> 00:55:39,445
manipulation of data -
these are simple matters to track.

816
00:55:39,480 --> 00:55:43,040
The thing about all fraud - however
complex they look to the outsider,

817
00:55:43,075 --> 00:55:45,337
once you understand them,
they're simple.

818
00:55:45,372 --> 00:55:47,466
"Fraud" is a big word
to use in science,

819
00:55:47,501 --> 00:55:49,525
and you've said it's littered
with it.

820
00:55:49,560 --> 00:55:52,840
Equally, scientists have made a
genuine attempt to do analysis

821
00:55:52,875 --> 00:55:55,205
and then someone says,
"You missed out this. "

822
00:55:55,240 --> 00:55:58,820
No, that's known as falsification.
That's a perfectly proper process.

823
00:55:58,855 --> 00:56:02,400
If, on the other hand, you find
all those departures from accuracy

824
00:56:02,435 --> 00:56:05,480
are in one direction and
one direction only, then you know

825
00:56:05,515 --> 00:56:07,365
that somebody is fiddling it.

826
00:56:07,400 --> 00:56:09,925
It's absolutely clear
- it works every time.

827
00:56:09,960 --> 00:56:13,200
Such a demoralising view of science.
I just don't see it...

828
00:56:13,235 --> 00:56:16,765
No, it's not a demoralising
of science - it's a view

829
00:56:16,800 --> 00:56:21,240
of those scientists who are trying
to bend the result. But you...

830
00:56:23,440 --> 00:56:30,280
To me, such attacks are a sure sign
that the scientific battle is over.

831
00:56:30,315 --> 00:56:34,165
And, sure enough,
perhaps the most surprising thing

832
00:56:34,200 --> 00:56:39,080
at the sceptics' conference is
what I heard at the keynote speech.

833
00:56:39,115 --> 00:56:42,400
Ladies and gentlemen, it is my
distinct pleasure to introduce

834
00:56:42,435 --> 00:56:43,560
Dr Patrick Michaels.

835
00:56:47,880 --> 00:56:50,485
Thank you.

836
00:56:50,520 --> 00:56:53,360
Thank you. Thank you very much.

837
00:56:53,395 --> 00:56:54,925
I'd like to talk to you

838
00:56:54,960 --> 00:56:59,160
about some convenient facts
on global warming, if I could.

839
00:56:59,195 --> 00:57:02,277
For years,
climatologist Pat Michaels

840
00:57:02,312 --> 00:57:05,576
has been one
of the most vocal sceptics.

841
00:57:05,611 --> 00:57:08,840
And yet today
he's in surprising agreement

842
00:57:08,875 --> 00:57:12,085
with the advocates
of global warming.

843
00:57:12,120 --> 00:57:14,565
There are, in fact,
two distinct warmings here -

844
00:57:14,600 --> 00:57:17,440
there's a warming of the early 20th
century and a warming

845
00:57:17,475 --> 00:57:18,885
of the later 20th century,

846
00:57:18,920 --> 00:57:22,325
which has some very interesting
characteristics, namely...

847
00:57:22,360 --> 00:57:28,000
He accepts the globe is warming,
but the truly astonishing thing

848
00:57:28,035 --> 00:57:31,760
is he also accepts that WE are
partly to blame.

849
00:57:31,795 --> 00:57:35,405
Fine. So global warming is real.

850
00:57:35,440 --> 00:57:37,685
In the second warming of
the 20th century,

851
00:57:37,720 --> 00:57:40,920
people have something to do with it.
All right? Now, get over it!

852
00:57:40,955 --> 00:57:42,805
OK, now you're all mad 
that I said that...

853
00:57:42,840 --> 00:57:46,005
You know, I've heard things here
that's really surprised me.

854
00:57:46,040 --> 00:57:49,940
I've heard things I really didn't
expect climate sceptics to say.

855
00:57:49,975 --> 00:57:53,840
They say global warming's happening,
temperatures are going up,

856
00:57:53,875 --> 00:57:57,365
and that humans are somehow
implicated in some degree.

857
00:57:57,400 --> 00:58:00,840
That's amazing. Those issues,
it looks like, are behind us.

858
00:58:00,875 --> 00:58:03,760
But that doesn't mean to say
the debate's over

859
00:58:03,795 --> 00:58:06,017
because there's a new debate
in town,

860
00:58:06,052 --> 00:58:08,240
and that is -
how bad is it going to be?

861
00:58:10,560 --> 00:58:12,760
In the next episode...

862
00:58:12,795 --> 00:58:14,600
There we go!

863
00:58:18,760 --> 00:58:21,925
.. the science of climate
change enters a new

864
00:58:21,960 --> 00:58:26,085
and even more controversial phase -
predicting the future.

865
00:58:26,120 --> 00:58:30,960
Just what will global warming mean
for our lives in the years ahead?

866
00:58:54,560 --> 00:58:56,500
Subtitles by Red Bee Media Ltd

867
00:58:56,535 --> 00:58:58,440
E- mail us: subtitling@bbc. co. uk