城市化世纪的自然（英文版）_85页_34mb

Summary of Nature in the Urban Century

Core Content

This report, Nature in the Urban Century, presents a global assessment of the impact of urban growth on biodiversity and human wellbeing, emphasizing the need for integrated urban planning that includes nature conservation. It outlines the challenges and opportunities presented by the urban century, a period marked by rapid urban expansion and the increasing role of cities in global environmental processes.

Main Points

Urban Growth Trends

• Population Increase: By 2050, the global urban population is expected to increase by 2.4 billion, equivalent to building a city of London every 7 weeks.
• Land Urbanization: Humanity will urbanize an area of 1.2 million km², larger than the country of Colombia.
• Drivers of Urban Growth: Economic growth, demographic changes, technology, cultural influences, and governance are key factors driving urban expansion.
• Challenges in Forecasting: Historical data and alternative future scenarios are used to project urban growth, but there are uncertainties in how these trends will unfold.

Impacts on Biodiversity

• Habitat Loss: Urban growth has historically been a major cause of natural habitat loss, responsible for 16% of the total habitat loss between 1992-2000.
• Biomes Affected: Temperate forests, deserts, and tropical moist forests are particularly vulnerable.
• Projected Loss: By 2030, urban growth could threaten 290,000 km² of natural habitat.
• Key Biodiversity Areas (KBAs): 49,000 km² of conservation action could help protect KBAs at risk from urban growth.

Impacts on Protected Areas

• Proximity to Urban Areas: In 1992, 29% of strictly protected areas were within 50 km of urban areas; this is projected to increase to 40% by 2030.
• Negative Impacts: Urban areas can lead to increased poaching, illegal logging, vegetation damage, and changes in disturbance regimes and abiotic conditions.
• Management Challenges: Increased proximity raises the likelihood of negative impacts and increases management costs.

Implications for Climate Action

• Carbon Storage: Urban growth could destroy natural habitats storing 4.35 billion metric tons of CO₂, equivalent to emissions from 931 million cars in one year.
• Social Value: Avoiding carbon release from habitat loss due to urban growth has a social value of $182.8 billion.
• Coastal Resilience: Coastal habitats reduce risks of flooding and erosion, but urban expansion could threaten these services.
• Climate Adaptation Services: Natural habitats provide essential services like flood reduction and temperature regulation, which are vital for climate adaptation.

Key Solutions

Planning for a Natural Future

• Integrate Local Governments: National governments should involve local authorities in planning and allocate resources to support urban conservation.
• Empower Cities: Urban growth plans should include biodiversity and ecosystem service considerations, using "greenprints" to guide sustainable development.
• Leverage International Institutions: Funding bodies like the GEF and Green Climate Fund should prioritize investments in urban conservation and EBA projects.

Create a CBD for the Urban Century

• Urban Target: The CBD should consider an urban-specific target or metrics to measure progress toward Aichi Target 5 and 11.
• CBD and COP-14: The 2020 COP-14 meeting is seen as a pivotal moment for biodiversity commitments, potentially leading to a new global framework.

Conclusion

The urban century presents both opportunities and challenges for biodiversity and human wellbeing. The report underscores the importance of integrating nature into urban planning and calls for urgent action to ensure that urban growth does not come at the expense of natural ecosystems. It advocates for a coordinated global effort to protect and enhance biodiversity in and around cities, aligning with the goals of the CBD, UNFCCC, and other international institutions.

Key Figures

• Urban Growth by 2050: 2.4 billion more people in cities.
• Habitat Loss (1992-2000): 190,000 km².
• Projected Habitat Loss (2000-2030): 290,000 km².
• Carbon Emissions Equivalent: 931 million cars for one year.
• Social Value of Avoiding Carbon Loss: $182.8 billion.

Key Authors and Partners

• Coordinating Lead Authors: Robert I. McDonald, M'Lisa Colbert, Maike Hamann, Rohan Simkin, Brenna Walsh.
• Lead Authors: Fernando Ascensão, Melissa Barton, Katie Crossman, Misty Edgecomb, Thomas Elmqvist, Andrew Gonzalez, Burak Guneralp, Dagmar Haase, Oliver Hillel, Kangning Huang, David Maddox, Andressa Mansur, Joel Paque, Henrique Miguel Pereira, Jennifer Rae Pierce, Richard Weller, Karen Seto, Mika Mei Jia Tan, Carly Ziter.
• Contributing Authors: Becky Chaplin-Kramer, Kytt MacManus, Richard Sharp.
• Reviewers: Pippin Anderson, Kobie Brand, Andrew Deutz, Amy Fraenkel, Perrine Hamel, Linda Krueger, Pascal Mittermaier, Harini Nagendra, José Antônio Puppim de Oliveira, Hugh Possingham, Anne-Hélène Prieur-Richard, Lynn Scarlett, LaTresse Snead, Ellika Török, Ernita van Wyk, Weiqi Zhou, Mark Zimsky.
• Designers: Paul Gormont - Apertures, Inc.
• Partners: CitiesWithNature, futurearth, Stockholm Resilience Centre, Stockholm University.

Methodology

• Urban Growth Analysis: Uses historical and projected data to assess urban expansion.
• Habitat Loss Analysis: Quantifies habitat loss due to urban growth.
• Carbon Analysis: Evaluates carbon storage and emissions associated with habitat loss.
• Coastal Analysis: Focuses on the role of coastal habitats in climate adaptation.

This report serves as a critical tool for policymakers and international institutions to guide sustainable urban development and biodiversity conservation in the coming decades.