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Concrete Jungles: The Surprisingly Rich Biodiversity Of Big Cities

Vast urban areas are home to much more animal and plant life than you might think, making their natural spaces crucial in the fight against global warming.

Monkey in Rio de Janeiro, Brazil
Monkey in Rio de Janeiro, Brazil
María Paulina Baena Jaramillo

BOGOTA — Can cities really become home to a large variety of fauna and flora? Doesn't the wild world hate cement? The concept of biodiversity may seem to contradict the nature of cities, but scientists, designers and architects are working on urban development models that harmonize with the natural world.

The world is increasingly urban. If current trends continue, the metropolitan area of Bogota, for example, will triple between 2000 and 2030, and the city population will double, from three million to almost five million.

Globally, this urban expansion will use up both space and natural resources, especially water and farming land. It will happen more in regions with fewer economic capabilities and faster in regions with more biodiversity, as a 2012 report on biodiversity and cities concluded. This should not surprise us, as areas of rich biodiversity are precisely those that have always attracted human settlements and fomented trade.

The evidence about the presence of a wealth of fauna and flora in large cities may come as a surprise. More than 50% of flower species in Belgium are in Brussels, and Warsaw is home to 65% of all bird species in Poland. A study of 61 gardens in Sheffield, England, found 4,000 types of invertebrates, 80 types of lichens and more than 1,000 plants.

There are significant nature reserves in cities such as Bombay, Stockholm, Nairobi, Cape Town and Tucson, Arizona, all of which make crucial contributions to biodiversity in those cities.

These spaces improve the health and well-being of city residents by cutting noise and air pollution. "They are not so much complementary and secondary as vital to cultural activities, physical and mental health and the identity of a place," says María Angélica Mejía of Bogota's Humboldt Institute

In Sacramento, California, park joggers under 65 years old typically spend $250 less on medicines than people who don't exercise. Other studies show that proximity to trees can reduce child asthma and allergies.

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Squirrel in Oakland, California — Photo: Kai Schreiber

Where there is carbon, plant green

Cities are currently thought to emit 70% of all greenhouse gases, but also feature a range of green spaces, from parks and woodland to greened roofs that are vital in mitigating climate change and storing carbon. These are the "soft infrastructures" that regulate the microclimate — the weather immediately around them — filter rainwater and absorb smog and excess dust. A study for the UK found that a 10% increase in city green cover reduced temperatures by three to four percent, which in turn reduced the use of air conditioning.

Current legal frameworks for protecting biodiversity include the UN Convention on Biological Diversity signed by 193 parties in 1993, and Colombia's own National Biodiversity Policy, adapted for Bogotá and Medellín, though only the latter has developed an action plan to implement its provisions, initially in the form of pilot projects.

Luis Germán Naranjo, the conservation chief for the World Wildlife Fund in Colombia, cites the country's isolated interventions to rescue biodiversity, such as saving Bogota's wetlands and revitalizing the banks of the Sinú river in Montería. But he adds that "management of biodiversity in Colombian cities is ever precarious. Parks, for example, are seen as recreational spaces, not ecosystems that improve air quality or as habitats for plant and animal species."

Conservation International's Patricia Bejarano says Colombia has barely begun to make the link between cities and biodiversity. "For a long time nobody paid attention in city planning to issues of biodiversity and its benefits. Now environmental problems have become more serious and more relevant around the world," she says. "Cities like Bogotá, Medellín and most recently Montería have made some advances in recovering ecosystems and their regional suroundings, and this has been through linking the environment with development plans."

City development and biodiversity must now be systematically linked, she suggests. She cites examples of the ravines that have been restored in Bogotá to become tourist destinations and appreciated by the capital's residents. "It is interesting how in Bogotá, the recovery of certain gorges has allowed citizens to understand the real importance of ecosystems, not just for preventing or mitigating risks but to improve air quality," she says. "And the proof of this is that most people have begun opposing building projects in the city's eastern mountains."

Cities must change their perspectives on development, neither halting construction because of biodiversity, says Humboldt's María Angélica Mejía, "nor abandoning everything that is green."

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What's Spoiling The Kids: The Big Tech v. Bad Parenting Debate

Without an extended family network, modern parents have sought to raise happy kids in a "hostile" world. It's a tall order, when youngsters absorb the fears (and devices) around them like a sponge.

Image of a kid wearing a blue striped sweater, using an ipad.

Children exposed to technology at a very young age are prominent today.

Julián de Zubiría Samper


BOGOTÁ — A 2021 report from the United States (the Youth Risk Behavior Survey) found that 42% of the country's high-school students persistently felt sad and 22% had thought about suicide. In other words, almost half of the country's young people are living in despair and a fifth of them have thought about killing themselves.

Such chilling figures are unprecedented in history. Many have suggested that this might be the result of the COVID-19 pandemic, but sadly, we can see depression has deeper causes, and the pandemic merely illustrated its complexity.

I have written before on possible links between severe depression and the time young people spend on social media. But this is just one aspect of the problem. Today, young people suffer frequent and intense emotional crises, and not just for all the hours spent staring at a screen. Another, possibly more important cause may lie in changes to the family composition and authority patterns at home.

Firstly: Families today have fewer members, who communicate less among themselves.

Young people marry at a later age, have fewer children and many opt for personal projects and pets instead of having children. Families are more diverse and flexible. In many countries, the number of children per woman is close to or less than one (Singapore, Taiwan, South Korea, Hong Kong among others).

In Colombia, women have on average 1.9 children, compared to 7.6 in 1970. Worldwide, women aged 15 to 49 years have on average 2.4 children, or half the average figure for 1970. The changes are much more pronounced in cities and among middle and upper-income groups.

Of further concern today is the decline in communication time at home, notably between parents and children. This is difficult to quantify, but reasons may include fewer household members, pervasive use of screens, mothers going to work, microwave ovens that have eliminated family cooking and meals and, thanks to new technologies, an increase in time spent on work, even at home. Our society is addicted to work and devotes little time to minors.

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