Biodiversity in an Urbanized World



Download Paths to sustainability S.M.A.R.T. (PDF)


Feeding the ever growing world population, particularly in developing countries, in a more and more urbanized environment and a warmer planet is one of the most important challenges facing mankind. “Biodiversity is life. Biodiversity is our life,” this was the slogan of the worldwide celebration in 2010 of the International Year of Biodiversity.

Healthy ecosystems provide social, economic and ecological benefits as well as goods and services that underpin the world economy and, thereby, human well-being. However, according to the Global Biodiversity Outlook during the last decades human beings have changed ecosystems more rapidly and intensely than ever before in the history of humanity. Biodiversity is being lost at an unprecedented rate, thus threatening the very capacity of the ecosystems to continue providing their vital goods and services.

A recently released study reveals that during the last two decades our planet has lost 10 percent of its wilderness areas. Since 1990 more than 3 million square kilometers of wild areas, amounting roughly to the size of India, have been lost.

This is occurring despite the international community convened at the Rio Summit committing, through the adoption of legally binding international treaties such as the United Nations Convention on Biological Diversity, to conserve and sustainably use biodiversity.

Until recently 47 percent of the Earth’s surface was covered in forest. By now, however, forest cover has completely vanished in twenty-five countries, and only 10 percent remains in twenty-nine others. Every year 13 million hectares of forests continue to disappear, the equivalent to an area three times larger than Belgium. It is a well-established fact that tropical forests are the richest ecosystems in the planet in terms of biodiversity. Although they only represent 7 percent of the world’s surface, tropical forests currently house up to 80 percent of all identified living species. And yet, approximately 35 percent of all mangroves have been destroyed in the last twenty years.

The extinction of animal and plant species is now between one hundred and one thousand times higher than the natural rate. As demonstrated by the Millennium Ecosystem Assessment, the pressures exerted on the planet’s natural functions by human activity have reached such destructive levels that the ecosystems’ ability to meet the needs of future generations is now seriously, and perhaps irretrievably, compromised.

Scientists are of the view that humanity is in the midst of the sixth global mass extinction of species. For many biologists the fate of biological diversity for the next ten million years will almost certainly be determined during the next 50–100 years by the activities of a single species: Homo sapiens.

The accelerated urbanization of the developing world, particularly in Africa, compounded by the negative effects of climate change, is among the root causes of the accelerated loss of biodiversity we are experiencing.

Since 2007 the world has witnessed a paradigm shift. For the first time in the history of mankind the urban population has surpassed the rural population. Such an irreversible trend has ushered in a new age, “the Homo urbanus era.” The twenty-first century will be a century of cities. Such an unprecedented evolution will have far-reaching implications on the future of mankind and will shape modern society.


Urban population growth is one of the most dramatic recent changes affecting humanity. Two centuries ago only 3 percent of the world population lived in cities. Today, more than 50 percent does. Most of this growth is occurring in developing countries, which host the largest part of the planet’s biodiversity.

According to the United Nations Population Fund the world’s population will reach 9.2 billion in 2050, jumping by 2.2 billion people between now and then. Such an increase amounts to the total world population as recently back as 1950. During the last two centuries there has been a sevenfold upswing in the number of people living in the world. Such an expansion will continue to take place, mainly in developing countries in general, and in Africa in particular.

The thick of this surge will happen in cities. The urban population will increase by fifty million people every year, almost the entire population of Spain and Portugal combined. Over the three decades to come the urban population will grow by 1.1 million people every ten days.

In 1820, only three cities had a population of more than one million inhabitants—namely, Tokyo, Beijing and London. By 1900 that number had risen to sixteen, and by 1950 to fifty-four. Today more than 411 cities have a population in excess of one million people. Within two decades their number will rise to over one thousand. In 1950, only New York and Tokyo had a population of more than ten million inhabitants. Today there are more than twenty-two megacities—and all of them, with the exception of New York and Tokyo, are located in developing countries.

In India, the urban population has multiplied by six since its independence in 1947. According to some estimates more than seven hundred million rural residents, the equivalent to the entire population of Europe, will migrate to Indian cities between now and 2050. Meanwhile, in China in 2000 there were 3.7 million villages. That number has shrunk since to 2.6 million. Indeed, three hundred villages disappear in the country every day. Yet over the course of the next decade China will build 50,000 new skyscrapers, the size of ten New Yorks.

Before 2025 another 221 cities will reach the one-million-people threshold. Europe, however, only has thirty-five such cities. Ninety-five percent of the world’s urban population will be found in developing countries. Every month the urban population of developing countries will grow by five million people, and by 2050 it will have doubled.

The African continent will witness the most dramatically accelerated urbanization process in the world. A report issued by UNICEF in August 2014 titled Africa: Generation 2030 confirmed that the African population will continue to grow steadily until the end of the twenty-first century. In 1950 Africa represented 9 percent of the world population. In 2050 one quarter of all humanity will be African, and one child out of three will be African. The current African population is estimated to be 1.2 billion. It will reach 2.4 billion in 2050 and 4.2 billion by the end of this century.

Over the past half century Africa’s urban population has increased by a factor of eleven. In 1950, 14 percent of the African population was urban. Today 40 percent of the continent’s total population is found in cities and by 2050 that proportion will grow to 60 percent. Presently more than 350 million Africans live in urban areas. In 2050 their number will reach 1.2 billion people.

In 1950 not a single African city had a population of more than one million people. By 1960 only Johannesburg had broken through that threshold. Today the number has increased to more than forty. The population of Lagos in Nigeria is expected to double by 2030, reaching twenty-four million inhabitants, and the population of Cairo will reach twenty-five million.

The rate of urbanization in industrialized countries has reached 75 percent. However, these countries continue to lose large portions of their agricultural land, as well as their animal and vegetal diversity. The twenty-eight countries that form the European Union are losing 1,000 square kilometers of fertile land every year. In France 60,000 hectares are lost owing to urbanization. In Austria, about 12 to 15 hectares of agricultural land are being erased from the map every day. Every day, Germany transforms about 110 to 120 hectares of land into streets, houses and other buildings. Meanwhile the need for agricultural soil is increasing due to the rising population, which is growing by about eighty-five million annually.

In 2050 more than 75 percent of the world population will live in cities. At the end of this century, 90 percent of the world population will be urban. Come 2030 four out of five urban citizens of the world will live in developing countries. Cities represent only 2 percent of the land of our planet but consume 75 percent of its resources and generate 80 percent of the CO2 emitted in the world. Cities, however, have always shaped the world economy and influenced modern societies.

If mismanaged, the accelerated urbanization of developing countries may have a dramatic impact on the future of mankind. The lack of awareness by local leaders and policy makers in developing countries of the importance, value and services provided by nature counts among the major causes for this unprecedented loss of biodiversity. It is for this reason that the first of the twenty Aichi Targets contained in the 2011–2020 strategic plan for biodiversity adopted in 2010 by the international community is to ensure that “[b]y 2020, at the latest, people are aware of the values of biodiversity and the steps they can take to conserve and use it sustainably.”

Ill-conceived urbanization will greatly contribute to global warming. However sustainable and livable cities are part of the response to the challenges posed by climate change. The World Health Organization reports that in 2012 around seven million deaths, one in eight of total global fatalities, came as a result of air pollution exposure. This finding confirms that air pollution is now the world’s largest single environmental health risk. Reducing air pollution could save millions of lives. Trees not only provide oxygen, they also absorb air particles.

During the heat wave of the summer of 2003, which led to the death of more than twenty thousand people in France, the area of the Bois de Boulogne, owing to its vegetal cover, recorded temperatures three degrees centigrade lower than all other areas in Paris. It has been demonstrated that a vegetal cover of 10 percent can reduce the energy consumption of a city by 5 to 10 percent. It has also been demonstrated that cities with a large percentage of vegetal cover exhibit limited levels of violence. Furthermore, cities with a large number of public spaces promote the creation of strong social ties among their inhabitants.

Scientists in Montreal have demonstrated that the risk of anxiety is 21 percent higher for urban citizens, who are subject to 39 percent more mood swings. Meanwhile the risk of developing schizophrenia is twice as large for people born in cities than for rural dwellers.

To accommodate the increased urbanization of the world, we would need to build a new city of more than one million inhabitants every week. It is the way these cities are conceived which will determine the future of mankind.

Urbanization is not the enemy of sustainable development. Cities are not the problem: they are part of the solution. The former mayor of Curitiba, Jaime Lerner, rightly stated, “Cities are not necessarily the problem. They are necessarily part of the solution.”

Cities are not the enemy of nature. Paris has more than 2,000 animal species and almost the same number of vegetal species. While biodiversity is diminishing in rural areas, it is increasing in Paris, which boasts 15 square meters of green areas per capita; London offers 45 square meters per capita and Brussels 59; Berlin is home to more than 8,000 wild boars and 2,000 foxes. The vegetal cover of Singapore is more than 16 percent of the surface of the state-city, which is emerging as a worldwide leader of urban ecology. Montreal has more than 1.2 million public trees; cities like Barcelona, Bilbao, Los Angeles, Miami and Philadelphia have successfully reinvented themselves.

However, the loss of biodiversity is not a necessary consequence of human activity, nor are cities unavoidably doomed to unsound urban management. Sound urbanization and environmentally well-managed cities can and do exist. Nevertheless, the cities at the forefront of the promotion of biodiversity in urban areas have a responsibility to share their experience with other cities in the world. Indeed, even if urbanization is irreversible, it is the way it unfolds which will determine the future of our species.

It was against this backdrop, and guided by the motto of the 1992 Rio Summit on Environment and Development, “think globally and act locally,” that I took the initiative, in my capacity as the executive secretary of the United Nations Convention on Biological Diversity, to convene in March 2007 in Curitiba, Brazil, a meeting on “Cities and Biodiversity: Achieving the 2010 Biodiversity Target.” The mayors of cities that have hosted meetings of the Conference of the Parties (COP) to the United Nations Convention on Biological Diversity as well as mayors of cities hosting a United Nations chapter were invited to share experiences regarding the protection of biodiversity and discuss the various possibilities for cities to enhance their engagement towards the achievement of the three objectives of the convention. The Curitiba Declaration on Cities and Biodiversity was adopted by the representatives of the thirty-four cities which attended this meeting.

Parallel to the 9th meeting of the Conference of the Parties to the Convention on Biological Diversity, I convened in May 2008 in Bonn a meeting under the theme “Local Action for Biodiversity” to highlight the importance of urban biological diversity. The fifty mayors from thirty countries, representing over one hundred million urban dwellers, who attended this meeting adopted the “Bonn Call for Action on Biological Diversity.” This document was submitted to the high-level segment of the Conference of the Parties to the Convention, held with the participation of heads of state and government and more than one hundred ministers of the environment.

For the first time ever, for any United Nations environmental convention, cities spoke at the highest-level forum, thus setting a precedent for future meetings of the Conference of the Parties to the Convention and other related intergovernmental processes.

This initiative culminated with the convening of a city summit on biological diversity held in October 2010 in Nagoya, Japan in relation with the 10th Conference of the Parties. More than five hundred mayors and municipal leaders attended this meeting. For the first time a plan of action on sub-national governments, cities and other local authorities for biodiversity was adopted by the eighteen thousand participants representing the 183 parties to the convention. The objective of this plan is to:

a) Increase the engagement of sub-national governments and local authorities, in support of their parties, in the successful implementation of national biodiversity strategies and action plans, the Strategic Plan for Biodiversity 2011–2020, the 2020 target and the programs of work under the Convention on Biological Diversity.a) Increase the engagement of sub-national governments and local authorities, in support of their parties, in the successful implementation of national biodiversity strategies and action plans, the Strategic Plan for Biodiversity 2011–2020, the 2020 target and the programs of work under the Convention on Biological Diversity.

b) Improve regional and global coordination and exchange of lessons learned between Parties to the Convention on Biological Diversity, regional and global organizations, United Nations and development agencies, academia, and donors on ways and means to encourage and support local authorities to manage biodiversity sustainably, provide ecosystem services to citizens and incorporate biodiversity concerns into urban planning and development.

c) Identify, enhance and disseminate policy tools, guidelines, and programs that facilitate local action on biodiversity and build the capacity of local authorities to support their national governments in implementing the Convention on Biological Diversity.c) Identify, enhance and disseminate policy tools, guidelines, and programs that facilitate local action on biodiversity and build the capacity of local authorities to support their national governments in implementing the Convention on Biological Diversity.

d) Develop awareness-raising programs on biodiversity for local residents (including major groups such as businesses, local administrators, non-governmental organizations, youth and indigenous and local communities) in line with communication, education and public awareness strategies.

As demonstrated by the Paris Summit, held with the participation of more than 150 heads of state and government, climate change is one of the most important challenges facing mankind. As stated by the secretary of state of the United State of America Mr. John Kerry in February 2014 while visiting Indonesia, “climate change is an arm of mass destruction.”

Indeed, climate change has been identified as one of the main drivers of the unprecedented loss of biodiversity. According to the Intergovernmental Panel on Climate Change (IPPC) up to 30 percent of all known species may disappear before the end of this century as a result of climate change.

However, green cities are part of the solution to climate changes. Green cities are ideal partners for the successful implementation of the historical Paris Agreement on climate change.

Therefore, if the establishment of the climate and cities program through the C40 and the designation by the secretary general of the United Nations Organization of a special representative on “cities and climate change” is a welcomed initiative, a similar program on cities and biodiversity is urgently required. The need to establish a permanent platform on cities and biodiversity with a view to promoting best practices, lessons learned and exchange of experiences in the context of both North–South and South–South cooperation is urgently needed.

Victor Hugo said, “The most powerful army in the world cannot stop an idea whose time has come.” The establishment of a permanent forum on cities and biodiversity is precisely such an idea, and its time has come.



The former executive secretary, until 2012, of the Convention on Biological Diversity within the framework of the United Nations Environment Programme (UNEP), he has played a major role in promoting biodiversity at the top of the political agenda of the United Nations Organization. He was previously assistant executive director of UNEP and director of the Global Environment Fund Division. He also acted as cochair of the preparatory committee of the Paris Conference, rapporteur general of the preparatory committee of the Rio Conference on environement and developement, and vice prisident of the negociating committee of the desertification convention. He has studied at prestigious institutions such as the University of Nancy in France, where he took his doctorate in political sciences; St. John’s University in New York, where he earned a master’s degree in political and information sciences; and the University of Algiers, where he obtained his bachelor’s degree in law. He is currently an adviser to the World Future Council, an organization formed by personalities of recognized ethical stature that represents the interests of future generations by placing them at the center of political decisions. He is the founder and honorary president of the Friends of the Green Wave, an educational campaign that seeks to engage youth and children.

Download Paths to sustainability S.M.A.R.T. (PDF)

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s