Saving forests and water in a sinking cityIn recent years Mexico City has increasingly distinguished itself by its work on environmental issues – in areas such as air quality, transportation, and climate. Now the city has also taken on water supply, its biggest problem. Mexico City is a ‘sinking’ city with no freshwater springs, and its groundwater is depleted by up to 40 cm per year. The city government is now stepping up work to protect the woods surrounding the city, and is investing in new pipes, sewage systems, treatment facilities, rainwater collection and tree planting.
Keywords: water supply, reforestation, nature conservancy, REDD+, transport.
Mexico City is one of the world's five largest megacities. It sits in a topographical cauldron, surrounded by high mountains, on top of what was once a freshwater lake. This topography also contributes to the city's air pollution problems. Over the course of 500 years the lake has been emptied of water while much of the surrounding forest, which recharges the aquifer beneath the city, has been cut down. While the population has expanded rapidly since World War II, the city itself has started to sink, because of the amount of water pumped out from beneath it. The aquifer under Mexico City still contributes about half the city's water supply, causing it to drop by up to 40 cm per year. In addition, the city has water leakage in excess of 40%, due to worn-out pipes, and it has major problems with wastewater pollution. Residents' distrust of the quality of the water has made Mexico City one of the world's largest consumers of bottled water.
The Great Water Forest
Decades of attempts to solve the water problem have been insufficient. Although much of the forest surrounding the town has been protected, this has not prevented logging or continued urban sprawl. This applies to the Great Water Forest of 250,000 hectares south of Mexico City, which according to studies, contributes about two thirds of the water supply to the city's aquifer (see also New York). About 80% of the forest is under some kind of legal protection, and the Mexican National Commission for Knowledge and Use of Biodiversity (CONABIO) has designated it a priority region for conservation because of its importance for water supply and biodiversity. Despite this, the forest is destroyed at a rate of nine football fields per day due to illegal logging, urban sprawl, and highway projects – a rate that, if continued, would obliterate it completely within 50 years.
One reason for this situation is the absence of a comprehensive, integrated regional plan and subsequent monitoring of nature conservation. Such fragmentation is partly because the forest overlaps three political entities: the Federal District (Mexico City), the state of Mexico, and the state of Morelos. In addition there are three political levels: City, State, and Federal. Mexican and international organisations are working to protect the Great Water Forest, including Mexico City's Natural Resources Commission (CORENA), Greenpeace Mexico, Guardians of the Trees, Mexican Environmental Law Center, and indigenous peoples in Texcalyaca and Xalatlaco. At the Ninth World Wilderness Congress in 2009, a petition to protect the Great Water Forest with a regional plan was adopted, which led to the formation of a "think tank" of 70 organisations, with participants such as environmentally conscious landowners, governmental agencies, Mexican and international environmental organisations, researchers, and entrepreneurs.
Payment for Ecosystem Services
Another factor supporting hope since the turn of the millennium is Mexico's Payment for Environmental and Hydrological Services (PSAH) programme, which was introduced in 2003. This project has evolved into one of the largest programmes for Payment for Ecosystem Services (PES), and its focus is solely on the protection of forests. Instead of the trying to stop logging and urban sprawl by means of legal procedures, the Mexican National Forestry Commission (CONAFOR), which administers PSAH, offers payment to landowners who preserve and nurture peri-urban forest of great importance for water supply. Unlike many other PES programs, PSAH has a social slant: since the land reforms of 70 years ago, much of Mexico's forests are collectively owned by poor, small communities (ejidos) and indigenous peoples. Between 2003 and 2006 about 300 ejidos annually signed contracts covering some 150,000 hectares of forest – and the programme has expanded since then.
In recent years Mexico has also taken a leading role in REDD+, the enhancement of the UN programme "Reduced Emissions from Deforestation and Forest Degradation" (REDD), which aims to reduce deforestation and degradation of forests in developing countries by means of trading in emissions. REDD+ also includes the role of conservation, sustainable management of forests, and enhancement of forest carbon stocks.
Green Plan with new measures
Mexico City's increased environmental work effort also inspires hope. Since the city launched its "Green Plan" in 2007, it has: protected 13,600 hectares of significant land; created a system for monitoring protected areas; and initiated a reforestation programme by planting 2.5 million trees per year. Almost 60% of the Federal District is made up of protected natural areas. On top of this, Mexico City is planning to launch its own PES programme for forests. In order to improve its water supply, the city is replacing all worn out water pipes by 2012, improving the drainage system, building new water treatment plants, constructing reservoirs and wells for rainwater collection, and restoring two major river basins (see also Singapore).
In the Siemens Green City Index for Latin America (2010), Mexico City ranked high in the category "environmental governance", for its environmental monitoring, ambitious programmes, and broad public participation. The city is investing over a billion dollars a year – 8 percent of its budget – in its Green Plan which is supported by the UN and the World Bank and contains 76 goals to be implemented by the year 2022. Of these, 22 had been achieved, and 31 had been achieved by half 2011. In 2008, the city also launched an action plan on climate change aimed at reducing greenhouse gas emissions by 12% by as early as 2012.
Environmentally friendlier transport
Mexico City's environmental efforts began in the early 1990s with a major relocation of the city's industry, in order to do something about air pollution. Mexico City topped the list of the world's most polluted cities (see also Delhi). Air quality has improved considerably since then, due to switching to cleaner fuel for buses and taxis, etc., and the city's environmental efforts have expanded accordingly. Transportation has become more sustainable through a range of measures: Metrobus (a modern system for Bus Rapid Transit transportation), a new subway line, modernisation of the taxi fleet, car-free days and an investment in cycling through the expansion of bicycle lanes and through the modern bike-sharing system Ecobici. The city has also become greener through the sponsoring of green roofs and campaigns for tree and shrub planting. Waste disposal too is slowly improving through waste sorting, packaging regulations, and the closure of landfills.
Mexico City Experience, Green Living, http://www.mexicocityexperience.com/green_living/
Latin American Green City Index, Siemens, http://www.siemens.com/entry/cc/features/greencityindex_international/all/en/pdf/mexicocity.pdf
Katalina Engel, Dorothee Jokiel, Andrea Kraljevic, Martin Geiger, Kevin Smith, 2011, Big Cities. Big Water. Big Challenges. Water in an Urbanizing World., A WWF Report, http://www.wwf.se/source.php/1390895/Big%20Cities_Big%20Water_Big%20Challenges_2011.pdf
Beatriz Padilla, Francisco J. Romero, Fernando Jaramillo Monroy, Flora Guerrero Goff, Raúl García Barrios, "The Water Forest of Mexico City: A Vital but Imperiled Urban Wilderness", International Journal of Wilderness, August 2008, http://www.wilderness.net/library/documents/IJWAug08_Padilla.pdf
Emily Loose, "Action for Mexico’s Water Forest", The Wild Foundation, August 2 2010,
Nicholas DuBroff, 2009, Curbing informal urban growth with ecosystem services in Mexico City, http://siteresources.worldbank.org/INTURBANDEVELOPMENT/Resources/336387-1272506514747/Dubroff.pdf
Branka Buric, Jean Gault, François Bertoye, 2011, Payment for Environmental Services: First Global Inventory of Schemes Provisioning Water for Cities, FAO Natural Resources Management and Environment Department, Land and Water Division, http://www.fao.org/nr/water/down/PES_Water_for_Cities.pdf
United Nations REDD Programme, http://www.un-redd.org/
Key data are retrieved from the UN World Urbanization Prospects: The 2011 Revision, http://esa.un.org/unup/unup/index_panel2.html