Burak Güneralp, Texas A&M University, College Station, TX, USA

Karen C. Seto, Yale University, new Haven, CT, USa

Presentation Title: Futures of global urban expansion: Uncertainties and implications for biodiversity conservation




Urbanization will place significant pressures on biodiversity across the world. However, there are large uncertainties in the amount and location of future urbanization, particularly urban land expansion. Presented is a global analysis of urban extent circa 2000 and probabilistic forecasts of urban expansion for 2030 near protected areas and in biodiversity hotspots. It is estimated that the amount of urban land within 50 km of all protected area boundaries will increase from 450,000 km2 circa 2000 to 1,440,000 km2 in 2030. Uncertainties in the forecasts of the amount and location of urban land expansion reflect uncertainties in their underlying drivers including urban population and economic growth. The forecasts point to the need to reconcile urban development and biodiversity conservation strategies.

Key Lessons Learned

  • The greatest increases in urban land around the protected areas (PAs) will take place in China, with the amount of urban land increasing as much as 3–7 times between 2000 and 2030.
  • Urbanization will place significant pressures on biodiversity across the world.  However, there are large uncertainties in the amount and location of future urbanization, particularly urban land expansion.

 Policy/Practice Implications

  • The varying levels of uncertainty in future urban expansion across different regions of the world also have important policy implications, especially considering these regions also differ in terms of their development levels. The most critical implication, however, is the brief window of opportunity in front of us for the next decade or two to develop and implement more robust urbanization strategies that explicitly consider biodiversity conservation.
  • For many regions, how urbanization will affect PAs will depend on the effectiveness and synergy of land use, conservation, and urbanization policies. Even in developed countries, the issue of effective governance of lands near PAs for preservation of ecosystem functioning and conservation of biodiversity remain unresolved. In the U.S., having a formal conservation mechanism that would allow for the management of lands around PAs to safeguard them against unwanted influences remains unaccomplished due to various political and cultural reasons. One is the fragmented jurisdictions of several bodies, while another is the lack of coordination between agencies and actors responsible for governing PAs and the lands around PAs, respectively.
  • In South America, mid-latitudinal Africa, India and Southeast Asia, the developing regions with the largest forecasted magnitudes of urban expansion near PAs after China, effective governance and management of PAs and surrounding lands will likely be challenging due to weak institutional capacity and lack of adequate financial resources. This challenge is especially acute for mid-latitudinal Africa that is forecasted to experience the greatest proportional increases in urban land. For example, according to our forecasts, the urban land within 50 km of Kilimanjaro National Park is expected to increase primarily due to rapid urbanization in and around Moshi, Tanzania—at the foot of iconic Mount Kilimanjaro, part of the Eastern Afromontane hotspot.

Knowledge Gaps and Needs

  • Findings highlight the need to consider future urban expansion and associated uncertainties in conservation planning. They also point to the need for more detailed national or regional analyses. This is especially the case for regions with substantial forecasted urban expansion near PAs and in biodiversity hotspots (i.e., China, mid-latitudinal Africa, South America, Western Asia and Southeast Asia). These regions have arguably the most at stake in terms of direct impacts of urban expansion on biodiversity.
  • Methodologically, there are inherent limitations to the urban expansion forecasts used in this study. Factors that were not included in the study, but may significantly influence regional and local urban land expansion include climatic factors, agricultural productivity, land use policies, international capital flows and infrastructure investment.
  • In Africa, Latin America, and Asia, the informal sector, which is not included in official GDP estimates, constitutes a substantial share of the overall economic growth. In addition, urban growth is often accompanied by construction of transportation infrastructure, which may have considerable impact on the spatial pattern of urban expansion. However, the model assumes a static road network ignoring potential construction of new roads. In addition, the model forecasts do not differentiate among various urban land uses or between formal and informal growth.