Why does climate change worry us? | Matilde Rusticucci | TEDxRíodelaPlata-TEDxChange |

Matilde Rusticucci is an expert on climate change and professor at University of Buenos Aires. She belonged to the Climate Change Experts Panel of the United Nations and shares some insights on the changes we may expect if we do not do anything to change the present.

The subject I wanted to talk to you about

is why we are worried
about climate change.

Climate change

is a thing that happens and has happened
since the beginning of the Earth.

That is what we call the climate system.

But, why a climate system?

The sun, which is the source
of energy of this whole system,

is the one that gives us energy,
radiates energy to our system.

Our system is composed
by the Earth, the ocean, the ices,

the atmosphere, the vegetation...

All these subsystems or little pieces
of this climate system

interact with each other.

Then we receive this radiation.

The Earth also emits radiation

that is trapped by the famous
greenhouse gases.

These gases,

part of those that make up the atmosphere,

are responsible for making
our living possible today,

and for giving us a nice temperature.

Greenhouse gases

are natural gases that exist
in the atmosphere.

But it's here where we have
to start realizing

that all of these subsystems
interact with each other.

What I mean is that if you change
any of these components,

this will affect the other
components in some way.

So, if you change the amount of radiation
that gets into the system,

or the amount of radiation
that gets out of it,

or the amount of ice
that could reflect radiation,

any of these changes
no matter how little they may seem,

will affect

the climate in our planet.

So, we know our climate has changed.

It can change for two main reasons:

natural reasons,

for climate has naturally changed
over millions of years.

We've been through ice ages
and interglacial periods, glacial ones...

We all remember all of this is measured

in hundreds or tens of thousands of years.

But climate can also change artificially

or inducted by the particular
action of man.

And it's there where we start worrying,
this is what we worry about.

Man is interacting with climate
in a way that is changing it

Why are we so sure about this?

We are so sure because of this graphic,
that seems a little too complex.

This is what we have to show.

We scientists,

from our international organizations,

this subject is discussed world-wide.

We can show, with that black curve,

what's the temperature observed

since the beginning
of the 18th century up to date.

This is the mean temperature
observed globally.

Well, we are able to know

how this temperature has changed

due to natural changes.

I mean,

changes in the amount of radiation
that enters the system,

due to changes in the Sun,
such as sunspots

and other changes the Sun suffers
in the amount of radiation it emits.

These changes would produce
the temperature following the blue curve.

As you see it is quite
below the black curve.

In order to reproduce
real temperature values,

we have to include man-made
changes in the analysis.

We are able to know that these two curves

are separated because of man-made actions.

If we were just having natural changes

temperature should be
much lower than today's.

And we can see differences
of, for instance,

more than half degree or one degree
Celsius, that seems little,

because this is a mean temperature
of the whole planet.

Global mean temperature:
summer, winter, poles, equator.

All of these, merged,
give us this mean temperature,

that may seem not so worrying.

But, what are we really worried about?

We see these changes,
we see how temperature,

in the upper chart, has risen

since 1850 until present.

We see it has a little
increase every year.

But it is increasing.

We see this accompanied not just
by temperature changes,

but also by increases in the sea level.

Why does the sea level rise?

The main cause for sea level
increases is this:

as the temperature
of the atmosphere rises,

the temperature of the water also rises.

The temperature of the ocean rises.

And when temperature rises,
there's an increase in volume.

As sea volume increases,
its level does so too.

So this is the main cause.

Of course, ice melting also contributes,

but that's not the main cause.

But we see how it has systematically
risen through the years.

And we see how, in the chart below,

the snow coat decreases, for example,
in the northern hemisphere.

That means we know there have been
changes in the whole climate system,

that are more easily illustrated,
for instance, by this case.

This is a glacier in Bolivia,
the Chacaltaya,

that has been photographed
in four occasions.

We see the glacier in 1940,
in the first picture up on the left.

Next one is from 1982.

Next is from 1996,
and the last one is from 2005.

We can see how the area covered

by this glacier has decreased.

This is a direct effect
of the temperature increase in this area.

This is Bolivia,
and that is a tropical glacier.

This is how we can show the impact it has.

We clearly see that the increase
of temperature locally,

although it seemed it had risen
just a little through the last centuries

-- only a degree Celsius
in almost more than one century --

the impact of these changes,
on a local scale,

is much stronger.

For example, in the case of glaciers,

if one glacier disappears,

there is a serious impact
on the surrounding population.

Generally, the people
that live around glaciers

drink their meltwaters.

Meltwaters from glaciers.

The water they usually use,

such as for drinking,
feeding, or cultivate,

comes from these glaciers.

If the glacier does not freeze in winter,

there will be no water
for these people in summer.

Then, we are observing this.

But how do we feel day by day
that the temperature has risen?

We've seen recent pictures
of the heat wave in Moscow.

The heat wave that hit Moscow in July,

and all the surrounding area in Russia,

had a big impact on the population.

The amount of deaths due

to fire pollution
and high temperatures doubled.

This had also happened
not so many years before.

In 2003,

there was another heat wave in Europe,

very significant, where 15 thousand
people died in Paris

only because of the high temperatures.

Europe is, therefore, having
more and more heat waves.

But what does this mean?

We're not necessarily having
the temperatures that Male suffered.

It doesn't mean Moscow had temperatures
above 40 or 50 degrees Celsius.

It's measured in another way.

What we see is that

temperature goes above certain level,

an amount of times per month.

For example: in Moscow in July,
a maximum temperature of 25 ºC

is exceeded normally nine days per month.

What happened that July?
It was exceeded 31 days.

Every single day in that July
exceeded that threshold.

So, day by day, what we feel

is that we have more and more days
with high temperatures

and less days with temperatures
below the threshold,

with cold and fresh temperatures.

This is an example from Moscow,

but our research team here
works on data from Argentina.

What has happened in Argentina?

What do we know that has happened here?

In our country and
in the South America region,

we've had, systematically,
less and less temperatures

under a threshold.

I mean, we have less
and less low temperatures.

Especially in summer, we have
a smaller amount of fresh nights.

That typical fresh summer night,

well, that happens much less often.

And every time we have more cases
of warm temperatures

in months that used to be milder

such as fall or spring.

So, hotter days have spread over the year

to October, to March,
even to April and May.

So, we clearly feel that everyday.

Not necessarily very high temperatures,

but especially temperatures
above the threshold.

But we've recently had
another extreme event

in the city of Buenos Aires
and its surroundings,

that were the southeast blows.

What is a southeast blow?

It's a wind coming from the southeast,
or east, that is very persistent

and does not allow the river
to flow into the Atlantic Ocean.

And we don't necessarily have
more and more southeast blows.

What happens is that this southeast blow,

added to a higher river level,

produces a bigger impact.

So, a change in climate will not

necessarily produce an equal impact.

The main consequences of the reports

that we submit

is that the poorest countries
are the ones to suffer more.

The countries with less
resources, less prepared,

faced to the same extreme climatic event

will have more losses.

They've had more losses

and more serious consequences.

This has nothing to do
with climate change,

but the Haiti earthquake
compared to the Chile earthquake

showed significant differences.

What do we know about future climate?

This chart, that seems
a little complicated,

perhaps you've already seen it.

We know what is going to happen

with a very level of certainty.

So we know that temperature,
that's been rising,

that first black curve you see
on the left, lower part of the graph,

that's what has happened.

What is going to happen?

It will depend on how society reacts,

what measures it takes.

To see which one of those curves,

if the red, the green,
the blue or the fuchsia one,

is going to be our future.

We know there will be
an increase in temperature.

And we know this increase will be higher

in the northern hemisphere.

Because the northern hemisphere
is a continental hemisphere.

The southern hemisphere
has a larger sea surface,

it reacts more slowly.

But, again, impacts could be different.

They're not necessarily related

to how big the increase
of temperature will be.

So, we know...

There are reports that show
all these types of results.

And all of these results emerge
from the reports of the IPCC,

that stands for

Intergovernmental Panel on Climate Change.

This is a United Nations panel,
created over 20 years ago,

which has obtained the Nobel Peace Prize

along with Al Gore

a couple of years ago,
for its accomplishments.

It's a panel formed by experts.

I am a part of this panel,
I was part of the former report

and I will be part of the one
we are initiating this year.

And these results, given its accuracy,

are elaborated through many years.

Just for you to know, the last report

came to light in 2007.

There was a huge worldwide impact,

and a lot of interest
in what results we were publishing.

That report was begun in 2004.

The next one is going
to be released in 2013.

And we have to have a first
draft for next march,

because it is largely revised by experts.

Every result is contrasted
with different published works.

So, what's the doubt?

Why are there sometimes
doubts about climate change?

There are doubts
because developed countries,

those which elaborate future policies,

take into account these reports.

From the results of the IPCC reports,

policies are made for the future,

these are the big things we have to do.

What can we do about it?

Well, there are two main areas:

adapt to the change,

and/or try to relieve it.

What does this mean?

Adapting to the change:
we know the change is happening.

We know the change will happen.

The better we know,

the more we know, and more precisely

how much the temperature will increase,

how will rains in the Pampas rise,

or how much it will stop
raining in Mendoza,

or in northern Patagonia.

The more we know about it,

the better we will be able
to adapt to these changes.

Actually,

man himself adapts
to those gradual changes.

But basically, what we have to do

is work to relieve the change.

To try to stop emitting,

to stop rising the concentrations
of these greenhouse gases.

I mean, we mainly need to stop
emitting carbon dioxide,

that comes from the use of oil.

From our homes, to save energy.

Try not to waste electric power

by refrigerating large buildings

that are architecturally very well built,

but are not eco-friendly,

because they need, for instance,
a lot of refrigeration.

It's well known that buildings

is where the cost-benefit of change
makes a big impact.

So, we know a lot of this stuff.

They're published in the reports.

Then, what is that worries us
so much about climate change?

Mainly, what worries us the most

is that no measures are being taken.

That no policies are being made
for these changes,

to adapt to the change,

so that the impacts do not
result so negatively.

And even to, in some way,
take advantage of some of these changes

for our country and our region.

Thank you very much.

(Applause)