Download Climate Change, Desertification and Rising Sea Levels

Drops of Water 11
Climate Change, Desertification
and Rising Sea Levels
Global climate change, desertification and rising sea
levels, the effects of which could seriously endanger the
equilibrium humans have attained in their environment,
are today a major priority for international organizations.
What does global climate change mean?
The earth is continually changing and always has done.
Climate changes too. However, the climate today is
changing more rapidly than it ever did in the past.
How can we observe this? To understand better, let’s first
consider the difference between weather and climate. By
weather we mean a meteorological event, a phenomenon
that occurs in a particular moment of time, and can last
an hour or several days, such as rain or sunny skies. If
we were to stay long enough by a window, we would be
able to contemplate the changing weather and seasons.
When we talk about climate, on the other hand, we mean
the average occurrence of weather conditions in an area
that have been continuously registered for at least 30
years.That is why we can say that the climate of Calcutta,
for example, is tropical ( hot and humid), that of Paris is
continental (hot summers and cold winters) and that of
Buenos Aires is temperate (mostly warm all year). The
average climate of the world is known as “global climate”.
Thanks to this type of recording activity, we can say
beyond a shadow of doubt that our planet’s climate has
changed rather quickly over the last decades. And the
conclusion is that our planet is getting warmer.
Illustration 1: © United States Department of Agriculture,
Natural Resources Conservation Service
The zones of the planet at risk of desertification.
Is global climate change new?
It is a well known fact that climate fluctuates and that the
earth has witnessed periods of extreme cold called ice
ages (when glaciers expanded) as well as milder period
known as interglacial (when glaciers withdrew towards the
poles). One after the other, these periods have occurred
over a period of thousands, even millions of years. In fact,
climate change is a slow and gradual process. Today we are
witnessing yet another fluctuation of world climate, the
difference being that now the changes are happening very
quickly, in particular over the last 150 years.
For example, the average temperatures of the Northern
hemisphere (Europe, North America, parts of Asia) have
been much higher as from 1950 than in any 50 year period in
the last 500 years.This rise in temperature has consequences
on the many natural resources and phenomena of our planet
that we have always taken for granted, and in particular on
water, perhaps the resource that is most sensitive to climate
change.
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Illustrations 3-5: © P. Laureano (2001),The Water Atlas,
UNESCO, see references, Centro Civiltà dell’Acqua
Desertification: vulnerability of the environment.
Illustration 2: © Helpsavetheclimate
Temperature variations of the last 1000 years.We can see
an abrupt rise in temperatures over the last century.
What effects of climate change can we observe?
What immediately comes to mind when we think of climate
change is rising temperature and this is amply confirmed
by temperature surveys.The years between 1995 and 2006
were amongst the warmest recorded since 1850, year in
which measurement of the temperature on earth began.
Global warming is thus a fact, and, although it is encountered
the world over, it is more pronounced in the regions near
the North Pole. Proof of global warming are everywhere,
from the reduced icing over period of lakes and rivers, to
the reduction of permafrost (land perennially covered in ice
such as Alaska or Siberia), to the rising temperatures of the
ground, the atmosphere and even the oceans.
Illustration 6: © UNDP United Nations Development Programme
The disappearance of lake Chad in Africa.
Illustrations 7-8: © German Research Center for GeoSciences (GFZ)
Catastrophic floods in Germany.
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If our planet heats up, the sea level rises.
As well as rising temperatures, a gradual but constant rise
in sea and ocean levels has occurred. During the 1900s,
on a world scale, there has been a rise of 17 centimeters.
Undoubtedly the melting of glaciers, icecaps and floes,
which account for much of the earth’s water reserve, has
played its part in this. Cold days and cold or freezing nights
have also been less frequent over the last 50 years whereas
hot days and nights have occurred more frequently.
Sea levels rise because water turns from ice to
liquid due to heat!
The warming of the earth’s surface has also contributed to
the disappearance of ice covered areas in recent years, an
ever accelerating phenomenon over the last few decades.
Satellite images show that the average annual extension of
the arctic ice caps has dropped by 2.7% per decade since
1978, and that it drops most significantly during the summer
months. We must also take into account the fact that
mountain glaciers and permafrost are rapidly disappearing
too.
WATER AT RISK
Water is directly linked to climate change since a rise in
temperature causes visible changes in the ecosystems.
The water cycle is deeply affected, which in turn has
consequences on the environment.
This means that if the climate changes and the planet
overheats, water will be the first to be affected, with varying
effects from region to region. For example, in the future,
certain areas may have less rain and therefore less water,
causing problems of drought and thirst for men, women,
animals and fields. Other zones may rather witness more
abundant rainfall and turbulent events, so extensive that
they can reap havoc on harvests, on homes, schools and
people.
What is desertification?
Desertification is the deterioration of the soils typical of
the arid, semi-arid and sub-humid zones of our planet,
mainly brought on by climatic shifts caused by the
excessive emission of greenhouse gas from human activity.
Desertification literally means “loss of soil fertility” and
it goes hand in hand with the advancement of desert. In
practice, it is a process of continual reduction of the ability
of ecosystems to sustain animal life and flora, since available
water is scarce or extremely difficult to regenerate. If there
is less rain and the days are hotter, crops dry up and don’t
mature, while the animals and people of arid zones where
water is hard to find can become ill more easily. Those
areas most at risk of desertification are: sub Saharan Africa
(bordering the Sahara desert), the Middle East, the countries
of the Mediterranean basin, some western parts of North
and South America. Indeed, almost all the zones surrounding
current deserts are at risk, and in the next few decades will
become more and more arid, or worse, turn into deserts
too.
So many hurricanes, whirlwinds and torrential
rain over the last few years. Has this always
been the case?
Extreme meteorological conditions, those that reap havoc
and damage, are not isolated to the last few years. It is well
known that natural calamities have continually struck the
populations of earth throughout history. However, when
we talk about “extreme meteorological conditions” we
are referring in particular to the fact that rainfall, in the hot
parts of the earth and surrounding areas, like the Sahel, the
Mediterranean and Southern Africa, is dwindling – whereas
it is increasing in northern Europe and some parts of
America and northern Asia.
There is, therefore, a continually greater risk of drought
in many zones for whom water supply will become
ever more critical. Returning to the effects of extreme
meteorological conditions, it is important to note that the
recording of the incidence of floods and droughts has also
greatly increased in the last thirty years thanks to new
systems of communication. It has also been observed that
climate-linked phenomena, like floods, torrential rain and
thunderstorms are dramatically on the rise, while other
cataclysms like earthquakes have remained much the same.
Illustration 9: © BBC UK - Australia and Nino Floods.
Illustration 10: © Practical Action Company UK Flood in Peru.
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What causes such rapid changes in climate?
It is now almost certain that the rise in average world
temperatures, with all the ensuing consequences we have
discussed, is largely due to the increase of greenhouse
gases, a direct product of human activity.
But can we really be the cause of all this? Scientists have
compared natural and human effects on climate fluctuation
and have observed a clear increase in temperature linked
to human activity. (IPCC 2007). We know, therefore, that
humans are significantly responsible for climate change.
Of course, collectively becoming aware of the necessity
for this is vital. Let’s take an example: the energy required
to switch on a lamp is obtained (generally) by burning
petroleum or coal, and this always entails an emission of
greenhouse gas. So each of us contributes to the emission
of greenhouse gas, however small the quantity.
One small step in this direction being taken now is the shift
from using fossil fuel energy to green energy that derives
from non polluting sources like the sun, wind and water.
If we choose this form of energy we can really help the
environment by reducing greenhouse gas.
What is greenhouse gas? How is it produced?
The overheating of our planet is mainly due to greenhouse
gas emissions produced by humans, in fact human activity is
a principal cause in the emission of these gases, in particular
carbon based fossil fuels like petroleum and coal.
Greenhouse gases do, however, occur naturally in the
atmosphere too, indeed they are responsible for allowing
the sun’s rays to reach the earth’s surface while at the same
time they block their exit from the atmosphere. If there
is too high an increase in these gases, an excessive rise
in temperature will result, because even if the rays that
penetrate earth’s atmosphere are the same, fewer can then
get out. As a consequence, the earth’s temperature rises.
Which human activities produce greenhouse gas?
Greenhouse gas is mainly emitted by humans due to the
combustion of petroleum and coal (more than 50%), but
not only.
The human activities implicated are:
•Electricity and heating (24.6%)
•Changes in soil use and deforestation (18.2%)
•Industry and industrial processes (13.8%)
•Transport (13.5%)
•Agriculture (13.5%)
•Refuse (3.6%)
•Other (12.9%)
Most of our activities, then, however small, are contributory
factors in the rise of greenhouse gas which is incredibly
harmful for our health and that of the planet. When we
use our car, when we leave the light on, when we eat or
even buy one product rather than another… each action
will have an impact on whether these emissions increase or
remain the same.
How can the increase of greenhouse gas be
stopped? And what can we as individuals do?
The main problem here is finding an international agreement
to stop these emissions by all the world’s countries. If we
want to achieve really meaningful results, the policies of
both the developed and developing countries must be
united in the fight to reduce these gases which are polluting
our atmosphere.
Illustration 11: © Greenpeace
Renewable energy can stop green house gas: solar energy is
the queen of clean energy sources.
Last but not least, here are a few little things we can do each
day to help our beloved planet:
•Learn to use less energy: always switch off the lights, keep
heating and air conditioning in the home to a minimum
(it isn’t necessary to have excessively hot temperatures
in winter and excessively cold temperatures during
summer), don’t leave the fridge door open, switch off
the small lights of household appliances when not in use
(there is no need to always leave them on standby…)
•Preferably choose “green” energy.
•Use public transport,or better, walk or go by bike whenever
possible! Cars pollute and produce greenhouse gas!
•Keep rubbish quantities to a minimum and make sure
all waste disposal is differentiated! Be careful with the
rubbish you throw away and make sure you don’t waste
paper, wrapping, etc.
•The food you eat is also of prime importance. Always
eat fruit when it is in season and which preferably comes
from your local area. That way all forms of pollution
related to production, transport and packaging will be
greatly reduced too.
Drops of Water 11
As you can see, what we must do is simply carry out a series
of relatively small actions. But these small actions all add up,
and along with those of others can make a real difference
to the health and safeguarding of our very beautiful, but
equally fragile planet!
Schmidt G., Wolfe J. and Sachs J. (2009). Climate Change:
Picturing the Science, Norton.
UNDP (2007). Human Development Report 2007-2008.
Fighting Climate Change: Human Solidarity in a Divided
World,The United Nations Development Programme.
Dossier compiled by:
Water Civilization International Centre, Venice:
www.civiltacqua.org
UNESCO (2009). Water in a Changing World, The United
Nations World Water Development Report, n.3, World
Water Assessment Program, UNESCO Publishing –
earthscan.
www.unesco.org/water/wwap/wwdr/wwdr3/pdf/
WWDR3_Water_in_a_Changing_World.pdf
UNESCO-UNCCD, Learning to Combat Desertification. A
Teacher’s Guide, UNESCO-MAB.
References
Archer D. and Rahmstorf S. (2010). The Climate Crisis:
An Introductory Guide to Climate Change, Cambridge
University Press, Cambridge.
Vlachos E. (2009). “Adapting to Climate Vagaries”, in
Climate Change and Natural Resources. Impact and Water
Challenge, Eulisse E., Ceccato L. (eds), Marie Curie Training
Course, University of Venice Ca’ Foscari – Civiltà dell’Acqua
International Centre.
Blaike P., Cannon T., Davis I.,Wisner B. (1994).At Risk: natural
hazards, peoples vulnerability and disasters. Routledge,
London 284 pp.
EEA (2009). Water Resources Across Europe: Confronting
Water Scarcity and Drought, Report, N. 2/2009, European
Environmental Agency.
Hulme M. (2009).Why We Disagree About Climate Change:
Understanding Controversy,
Inaction and Opportunity, Cambridge University Press,
Cambridge.
IPCC (2007). Climate Change 2007: Synthesis Report, (core
writing team: Pachauri R. K. and Reisinger A.), Report n.
4, Intergovernmental Panel on Climate Change, Geneva,
Switzerland
Rockström J., Falkenmark M., Karlberg L., Hoff H., Rost S.
and Gerten D. (2009). Future water availability for global
food production: the potential of green water for increasing
resilience to global change, Water Resources Research 45:
W00A12, doi:10.1029/2007WR006767.
Venice Office
Regional Bureau for Science
and Culture in Europe
United Nations
Educational, Scientific and
Cultural Organization