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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.

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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