“Every tenth of a degree counts” Prof. Dr. Hans Joachim Schellnhuber on the security implications of climate change

10 Pages·2019·0.87 MB·English

by  Hans Joachim Schellnhuber, Metis Institute for Strategy and Foresight Bundeswehr University Munich (ed.)

Interview
“ Every tenth of a degree counts. ”
Prof. Dr. Hans Joachim Schellnhuber
on the security implications
of climate change
No. 1 | May 2019
The views expressed in Metis Interviews are those of the interviewees. They do not reflect the opinion
of the Bundeswehr, the Federal Ministry of Defence, or the Bundeswehr University Munich.

Metis Interview | No. 1
Security implications of climate change – Hans Joachim Schellnhuber
Interview
Climatologist Hans Joachim Schellnhuber
Interview between climatologist Prof. Dr. Hans Joachim Schellnhuber and
Prof. Dr. Carlo Masala, Director of Metis. The interview was recorded at the
Potsdam Institute for Climate Impact Research on 9 May 2019. The interview
has been abridged and edited for clarity.
Masala action. At the moment, however, we brutally disrupting it with our green-
Professor Schellnhuber, can you are heading towards 3 to 5 degrees house gas emissions. That is leading
explain to us in plain English Celsius by the end of this century, and to climate crises, the likes of which
the most important results of the temperature is not going to stop we have never experienced before in
the research into global climate increasing after that. the history of human civilisation. And
change? What exactly is happen- For another thing, the earth’s aver- now every tenth of a degree counts!
ing – and why? And what is the age surface temperature is the result It’s quite similar to the internal
significance of these 1, 2, 3 and of thousands of processes. For ex- body temperature of us humans. If
4-degree increases in temperature? ample, we have intense solar irradia- you were to leave this room now, the
tion over the equator and months of temperature in the corridor might be
Schellnhuber darkness in the polar regions. Atmos- 3 degrees colder. If you were to leave
It all has to do with the average glob- pheric circulation – redistribution the building, it might even be 10 de-
al temperature on the earth’s surface, processes of warm and cold air – are grees colder. But your body tempera-
measured on the ground and over happening constantly. We also have ture doesn’t change as a result of that.
the oceans. And of course, many peo- sea currents such as the Gulf Stream It is kept within a very limited range
ple ask: “Why is this so important? that carry warm water from the Car- through a series of processes – per-
We’re talking about a change of just ibbean and similar regions all the way spiration, respiration, circulation, and
1.5, maybe 2 degrees.” here. Our forests also have a cooling so on. Between 36.5 and 37 degrees
But that’s inaccurate in several re- effect, mainly through evaporation. Celsius if you’re healthy. If your body
spects. For one thing, limiting global There are countless mechanisms that temperature were to increase by 1
warming to 1.5 or 2 degrees Celsius balance out the earth’s temperature degree right now, you’d already start
would be a major success, but one conditions. It is an incredibly com- to feel slightly unwell. If it were to in-
that would require decisive political plex and delicate balance. And we are crease by 2 degrees, then you’d have
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Metis Interview | No. 1
Security implications of climate change – Hans Joachim Schellnhuber
a fever. From 39.5 degrees, things this radiation tries to leave our at- have increased the long-term maxi-
would become downright unpleas- mosphere, however, CO₂ springs into mum value of this environmental in-
ant. An increase of 5 degrees, and action: It is able to absorb the longer- dicator for our planetary system by
that’s it – game over. And that is ex- wave thermal radiation much better about 50 %!
actly what we need to keep in mind than visible light because thermal
when discussing the change in the radiation causes it to vibrate at cer- Masala
earth’s average temperature. That is tain frequencies. In other words, CO₂ Against this backdrop, can
why we’re raising the alarm over an works like a crazy doorman who lets you give us an idea of what
increase in temperature of 1 degree, 2 in almost anybody who is sober but a best-case and worst-case
degrees, 3 degrees Celsius etc. then won’t let people leave again scenario would look like?
This brings us to the issue of CO₂ . when they’re drunk. This complicat-
The fact that the earth is habitable ed warming-up process raises the Schellnhuber
at all is closely linked to what we earth’s average temperature. That is Well in a sense, we are attacking
call the natural greenhouse effect. why we have a climate that makes this highly complex system with a
If we had no CO₂ in the atmosphere, life on earth possible in the first sledgehammer. And so it should
the earth would be an average of place. come as no surprise that something
about 35 degrees cooler. The aver- But now to the heart of the mat- dramatic is unfolding. To come back
age global temperature would be ter: CO₂ is a trace gas – its natural to my previous comparison: The cur-
around minus 20 degrees Celsius. volume fraction in the atmosphere rent temperature increase of more
There would be virtually no water (measured in ppm: parts per million) than 1 degree would be enough to
anywhere in liquid form. But water is well below one-tenth of a percent. cause a slight fever in a human being.
is the origin of life, which is why at- Nevertheless, its influence on the If we were to bring all emissions to a
mospheric CO₂ is so important. At- earth’s temperature balance is tre- halt overnight, the system’s delayed
mospheric CO₂ has the phenomenal mendous. Over the last 2 to 3 million reaction and other effects would
physical property of allowing the years, which is the period in which likely cause the temperature to con-
visible spectrum of sunlight, which is our present environment developed tinue to increase by just under half a
of course essentially the energy that and during which Homo sapiens degree. This would put us at almost
powers our life, to pass through free- emerged about 300,000 years ago, 1.5 degrees. This would be the best
ly. When it comes to sunlight from there was a constant back and forth case of a fever that is still bearable.
above, CO₂ says: “Nothing for me to between warm and cold periods. For But if we were to double the
worry about.” Radiation in the visible extensive parts of this period, the CO₂ pre-industrial CO₂ content in the at-
spectrum is also reflected back out content in the atmosphere fluctuat- mosphere – and this will happen as
of the atmosphere, partly from the ed between about 180 and 280 ppm. early as the middle of this century
unless we take drastic action now
– then we would probably see an in-
crease of 3 degrees. And if we were
Since the Industrial Revolu-
to just carry on after that – which,
at present, is looking unfortunately
tion, we have burnt through
likely – then we could bring about a
rise in temperature of 4 or 5 degrees
enormous quantities of fossil fuels,
Celsius over the course of this cen-
tury. That would be the worst-case
as a result of which CO₂ levels are
scenario. To come back to the com-
parison I drew with the human body:
now as high as 415 ppm.
game over.
When it comes to the earth as a
system, the equivalent to vital organs
that fail when the body overheats is
what we refer to as the tipping points.
This is of course where the major
deserts, the ice sheets etc. But when But since the Industrial Revolution, ecosystems come into the picture:
sunlight strikes dark ground in par- we have burnt through enormous the Amazon rainforest or the Great
ticular, it warms up the surface of the quantities of fossil fuels, as a result of Barrier Reef, about 40 % of which is
earth, which then emits thermal ra- which CO₂ levels are now as high as already dead as a result of the most
diation in the infrared region. When 415 ppm. This means that we humans recent heat waves in the ocean. Let’s
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Metis Interview | No. 1
Security implications of climate change – Hans Joachim Schellnhuber
not forget the vast ice sheets that for several months, continuously faster. At the same time, the ice be-
have existed for millions of years. The bringing in heat from the Sahara to comes brittle, rough and dirty, which
Greenland ice sheet contains so much Europe. And then of course there means it can absorb even more sun-
ice that, if it were to melt complete- is the Gulf Stream in the Atlantic, light, thus becoming warmer even
ly, the global sea level would rise by which gives western Europe its mild faster and melting even faster. So
seven meters. Imagine what Europe’s climate even though we are on the we are talking here about a self-ac-
coastlines would look like as a result. same latitude as Alaska. If it weren’t celerating process. And once this
Another extremely relevant factor for this permanent remote hot-water process gets going, there’s nothing
are the major circulation patterns heating, we would have Alaskan con- to hold it back. When will we reach
in the atmosphere and the oceans. ditions here, too. this tipping point? Our best estimate
Take the Indian summer monsoon Unfortunately, the first systems at present is that the downward spi-
as an example. About 500 million to collapse will be the tropical coral ral will start once global warming
people depend on this weather reefs. Around the globe, large parts crosses the 1.6-degree threshold. But
phenomenon to occur regularly of these reefs will probably die as there are still major uncertainties. Of
because almost half of South Asia’s a result of a temperature increase course I’m hoping that it will only
population is still employed in ag- of just 1.5 degrees. The Arctic sea begin at higher temperatures.
riculture. Then there’s jet streams, ice is also at urgent risk. And then The bottom line is that with its
which flow at high speed from west there are large parts of the Western aim of limiting global warming to
to east 10 – 12 km above the surface Antarctic ice sheet, where numer- 1.5 to 2 degrees, the Paris Agreement
of the earth. This air current is very ous ice basins seem to have already will protect us from some but not all
important for our weather in Eu- collapsed. But the big question is: major planetary disasters. But if we
rope. Last year, for example, we had When will Greenland begin to melt? fail to achieve the goals specified in
an abnormal situation that led to a Greenland’s ice sheet is up to 2 kilo- the agreement, we will lose our en-
summer of drought. The meanders metres thick. If the upper layer grad- vironment as we know it today and
of the jet stream, which are known ually melts, the surface will sink into will be putting the very basis of our
as Rossby waves, stayed in one place warmer regions – and then melt even existence at risk.
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Metis Interview | No. 1
Security implications of climate change – Hans Joachim Schellnhuber
Ultimately, this calls for a rapid
and profound transformation of our
global economic system. Personal-
T here’s no doubt that tackling
ly, I don’t believe we can sustain the
1.5-degree line without dangerous
climate change is necessary
extensive technological interference
with the planetary environment.
from a geostrategic perspective, too.
We can manage the 2-degree line,
though, provided we can overcome
two essential challenges. Firstly,
de-carbonisation, that is to say the
rapid replacement of fossil fuels with
renewable energies, more efficient
Masala Idiotically, some decision-makers procedures, more rational consum-
What effects do you think cli- still take the view that “unless you er behaviour, and so on – ideally by
mate change will have on scientists can guarantee with abso- 2040. We have long had the neces-
global security policy? lute certainty that all of this will hap- sary technical means at our disposal.
pen exactly the way you say it will, Secondly, we must stop overexploita-
Schellnhuber then we don’t need to do anything tion of our natural ecosystems, our
So let’s talk about the big issue of in- at all.” Imagine if the military were powerful friends who protect us from
ternational and national security. If to plan like this: “Unless I know with climate change mainly by absorbing
the scenario I’ve just described actu- absolute certainty that I’m going to and storing a large proportion of the
ally occurs, it is possible that not only win without any losses, then I won’t CO₂ we produce. In military terms: if
large parts of the tropics but also all defend myself in the first place.” But I have a strong ally, I would do well
coastal regions, where the main eco- this really is how some people actual- to try to maintain and support that
nomic activities on earth take place ly argue. We are causing massive dis- ally. We, on the other hand, are kill-
and where most people live, would ruption to the system from which our ing our best partners! One example
eventually become uninhabitable. civilisation was created. This is why is our practice of cutting down the
Billions of people around the world we must apply the precautionary rainforests in the tropics to make way
would have to relocate. Not today,
not tomorrow, but more and more
with every decade. Climate change
This twofold destruction of
can contribute to migration in the
short term as well, for example when
the system – firstly, emissions
a period of drought leads to crop fail-
ures, which can cause latent conflict
of greenhouse gases and, secondly,
in the affected region to turn violent.
And so there’s no doubt that tack-
overexploitation of nature – is a
ling climate change is necessary from
a geostrategic perspective, too. We
form of suicide.
must fight to prevent every tenth of a
degree because even minor changes
can push us over the edge towards
one of the major elements of the sys-
tem collapsing. As long as the mon-
soons in India or West Africa occur
somewhat regularly, for example, the principle. We know that an increase for soya bean farming. This twofold
agricultural societies there will sur- in temperature of 3 to 4 degrees Cel- destruction of the system – firstly,
vive. But if, for example, three years sius will cause devastating disasters, emissions of greenhouse gases and,
were to pass with no sign of an Indian but at the moment we are still – just secondly, overexploitation of nature
summer monsoon, only for the phe- about – in a position to maybe fend – is a form of suicide. As awful as that
nomenon to return with a vengeance, off the worst and most serious con- sounds – it’s true.
the food system would collapse. This sequences. This is why we must do And thirdly – and this is a particu-
could destabilise the whole of India everything we can to try to prevent larly important point in military and
as a country. any further global warming. security policy discourse – several
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Metis Interview | No. 1
Security implications of climate change – Hans Joachim Schellnhuber
hundred million people are likely to effect by further destabilising precar- However, we suspect that if we
relocate in some way or other even if ious regions. I’ll give you an example. were to enter a world where global
the climate changes only moderately. Between 2006 and 2011, Syria was hit temperatures have increased by 4 de-
Let’s hope we have enough time and by one of the worst droughts ever grees or more, the impact on the cli-
that we can do all this in an orderly recorded. As a result, harvests failed mate would be so drastic that it could
fashion. And hopefully we will be able and a lot of cattle perished. Hundreds become one of the main drivers of
to develop the tools we need to do it. of thousands of people in rural areas conflicts. Once we get to 6 degrees or
To believe that we could instead erect lost their livelihoods and sought ref- more, large parts of the tropics would
an impenetrable barbed wire fence uge in the outskirts of big cities such become physiologically uninhabit-
around Germany or the EU is simply as Homs and Aleppo. able, which means there would be
naive. Not to mention inhuman … California was also hit by a simi- areas in which we would not be able
larly extreme drought recently. Yet to survive outdoors for longer than a
Masala there was no civil war there, but few hours. 1 We would have to stay in
From the research you and your there certainly was in Syria. At this an air-conditioned environment at all
institute are doing, are there point, it’s important to emphasize times, something only the privileged
any results that suggest that that a conflict can erupt as a result of would be able to do. Or we would
climate change is the main cause several factors that are often difficult crowd into regions that have a mild-
of violent conflicts within or to quantify. But if there had been a er climate, with all the consequences
between countries? I am asking properly functioning social network that would have in terms of security.
because the debate in my field of in Syria and – rather than a brutal
research tends to be about the autocracy – a civil society with dem- Masala
idea that climate change does ocratic rights, freedom of the press Most countries in the Western
not actually cause conflicts but etc., it might still have been possible world, as we call it, recognise that
escalates already existing ones. to avert the crisis. Jordan, for example, climate change is going to affect
is relatively stable. And although the security policy in some way or
Schellnhuber drought in California was unpleasant another. This is usually debated
We are probably still at a point where because people couldn’t water their in connection with adapting our
climate change is indeed only a lawns, for example, life otherwise just own armed forces, for example in
co-factor and only has an indirect carried on as normal. terms of clothing, materiel etc., so
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Metis Interview | No. 1
Security implications of climate change – Hans Joachim Schellnhuber
that they can also function in high Mali or Niger, we must first and fore- of the equator. The nomads had to
or low temperatures. But this of most make sure that radical, militant flee south to the Sahel and then to
course can only be a first step. What or extreme forces do not exploit a Northern Nigeria, Cameroon and
consequences do you think there state of emergency. Chad. And so I witnessed how a rela-
might be for this narrow segment Finally, let me give you a personal tively small change – in this case two
of security policy? More specifi- example. The first time I personally years of no rainfall – can destroy en-
cally, what does the B undeswehr experienced the climate problem tire cultures. And that then triggered
have to be prepared for? was when I travelled through Africa a domino effect. If it hadn’t been for
between 1972 and 1974. It was my the Sahel drought back then, Boko
Schellnhuber love of adventure that first brought Haram might not even exist today.
Important as it is, needing to adapt
to changed climatic conditions under
which man and material have to act
Whether it wants to or not,
and function almost goes without
saying.
the Bundeswehr is going to
The real question is whether the
task spectrum of the Bundeswehr will
undergo further internationalisa-
change when geostrategic circum-
stances change. Where would crises
tion as a result of climate change.
and wars in particular have to be
prevented? Where could new threats
develop? And where might this make
it necessary to operate beyond our
own national borders?
Whether it wants to or not, the
Bundeswehr is going to undergo me there. That was at the time of Incidentally, we also know what
further internationalisation as a re- the devastating drought in the Sahel triggered the crisis back then. It was
sult of climate change. Science can region. The arid conditions were ex- not climate change but air pollution.
help, for example by developing an treme, particularly in the eastern part Aerosols, most likely from power
early-warning system for detecting of the Sahara. I witnessed it all first- plants in Western industrial countries,
where new tensions or even armed hand. Along the few roads through suppressed the rainfall. A German or
conflicts are emerging, what peaceful the Sahara desert lay dead cattle, the French coal power plant contributing
conflict resolution approaches can be nomadic people’s primary source to a devastating drought in Africa and,
taken, and where a force contingent of capital! It was a harrowing sight: from afar, destroying the circulation
may need to be deployed. dead camels left and right, and the patterns that usually bring rainfall to
As you can see, these are funda- Tuareg – once proud warriors – stood the region in spring … crazy, isn’t it?
mental questions. My answer would begging in the streets and sold their
of course be that conflict prevention silver jewellery for a pound of sugar. Masala
is crucial. In countries that are at the I believe this was the beginning Professor Schellnhuber, thank
centre of climate change, such as of the destabilisation of Africa north you very much for this interview.
Interviewee
Prof. Dr. Dr. h. c. Hans Joachim Schellnhuber, Director Emeritus
Hans Joachim Schellnhuber is Director Emeritus of the Potsdam Institute for Climate Impact Research (PIK),
which he founded in 1992. He is Distinguished Visiting Professor at Tsinghua University (China), and member of
numerous learned societies such as the Pontifical Academy of Sciences, the German National Academy Leopoldina
and the US National Academy of Sciences. Since 2019, Schellnhuber has been intensively involved in the crea-
tion of a “Bauhaus der Erde” and is currently member of the New European Bauhaus High-level roundtable.
Source: https://www.pik-potsdam.de/members/john
1 See "Inhospitable – A Short Story", Metis Study No. 11 (May 2019).
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Publisher
Metis Institute
for Strategy and Foresight
Bundeswehr University Munich
metis.unibw.de
Interview conducted by
Prof. Dr. Carlo Masala
[email protected]
Creative Director
Christoph Ph. Nick, M. A.
c-studios.net
Title image
David Mark at Pixabay
Photographs
Potsdam Institute for Climate Impact
Research (PIK)
Original title
Sicherheitspolitische Folgen des Klimawandels
Translation
Federal Office of Languages
ISSN-2627 – 0587
This work is licensed under the Creative Commons
Attribution 4.0 International License.