What is climate change?

"Climate change refers to changes in the long-term climatic conditions of an area, and is a result of both natural phenomenon, such as volcanic eruption, and human-induced changes in the atmosphere, such as an increase in greenhouse gas emissions". 

There is growing consensus within the international scientific community that anthropogenic forces, e.g., land use changes, widespread deforestation and the burning of fossil fuels, contribute significantly to climate change.

Warming of the climate system is evidenced by increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea levels. Since 1850, when weather stations around the world began measuring temperature fluctuations, 1995-2005 rank among the twelve warmest years in the instrumental record of global surface temperatures. 

While temperature increases are widespread around the world, temperatures have risen faster over land areas than over oceans. 

Indications are that greenhouse gas emissions, especially Carbon Dioxide and methane, have increased and intensified over the past 20 years, and cities have played a key, though not yet fully understood, role in this process. 

This temperature increase has led to changes in global and regional climate patterns, which, in turn, have impacted the lives of local communities and economies. Projections indicate that a 2 degree Celsius  warming above preindustrial levels could result in permanent GDP reductions of 4%-5% in Africa and Southeast Asia.

“We shape our cities and our cities shape us.” 

Cities create two main impacts on the carbon cycle and climate system, i.e., land use changes and changes related to emissions of aerosols, greenhouse gases and solid waste. 

Cities also rely on inward flows of food, water and consumer goods that may result in emissions from areas outside the city. Affluence and lifestyle choices also determine emissions.

Historically, greenhouse gas emissions have been greater in developed than in developing countries, but this pattern is quickly changing with rapid urbanization in the developing world. 

China has recently overtaken the US as the world’s leading emitter of greenhouse gas emissions even though its per capita emissions are significantly lower (In 2005, Chinese emissions per capita was about 6 tons compared to 25 tons for the US). Together, the US and China emit about 35% of total greenhouse gases.

The responsibility for urban emissions is not distributed evenly throughout the urban population within and across countries. 

The city’s geography, i.e., the climatic situation, altitude and location in relation to natural resources and demographic composition (age structure and household size), affects consumption behavior, greenhouse gas emissions and the contribution of urban areas to climate change. 

More importantly, the way in which urban areas are managed affects their contribution to climate change.

Urban form and spatial organization (density) can have a range of implications for a city’s emissions. The high concentration of people and economic activities in cities can lead to economies of scale, proximity and agglomeration that reduce per capita emissions. 

Urban infrastructure and development policies lock in the physical and institutional contexts for the way people travel and live their lives, and influence lifestyle choices, which in turn impact urban emissions, e.g., a lack of efficient public transit and low parking prices in the city encourage greater car use.

The Kyoto Protocol identifies and regulates six major greenhouse gases, i.e., carbon dioxide, methane, nitrous oxide, hydro fluorocarbons, perfluorocarbon and sulphur hexaflouride. 

These are generated by anthropogenic activities, with energy supply responsible for about 26% of global emissions (mainly from the burning of fossil fuels), transportation about 13%, commercial and residential buildings 8%, waste 3%, industry 19%, and agriculture and forestry 31%. 

In other words, power generation for electricity, heat and industrial activities, land use changes, such as deforestation and burning, industry, agriculture, including fertilizer use and livestock, and transportation, such as fossil fuel for automobiles, are important sources of emissions.

Land sharing

Land sharing is a form of land readjustment, usually referring to smaller scale, more local government and community-based efforts. 

While land readjustment is primarily a public-private (formal) alliance, land sharing may involve different actors and a range of formal and informal partnerships that develop where more than two actors may be involved depending precisely upon the local circumstances.

The concept behind land sharing partnerships is that the landowner (public or private) and the land occupants (squatters) reach an agreement whereby the landowner retains the most economically attractive part of the land parcel and the dwellers are allowed to build houses on the other part, usually with full tenure rights. 

In some cases, the public authority or the private owner may build the units and sell them to the previous occupants at subsidized rates.

During the 1980's and 1990's, innovative “land sharing” projects were implemented in Thailand and, more recently, on a larger scale in India. 

Such techniques, in principle, upgrade physical conditions, increase population density, and relocate households displaced from their original land on site. 

Legal owners of land are given an incentive to participate. If they agree to share the property with the informal residents, squatters will release part of the occupied land (generally between one-third and one-half depending on the circumstances), usually the part with the highest commercial value. 

The poor will buy or lease the remaining part of the land from the legal landowners, usually at below market prices. 

However, land sharing techniques, as well as larger scale land readjustment as discussed above, require a high level of community organization, intervention of mediators and other outside groups (such as NGOs), and support of public administrators and other stakeholders at the local level. 

In addition, the feasibility of up-scaling land readjustment and land sharing in most developing countries is still open to question. 

What drives the formation of suburban slums?

• Suburban slums in developing countries may be a simple extension of core city slums, driven by the rapid growth of low-income households.
• They may be the product of laxer enforcement regimes of local governments in suburban areas.
• They may reflect lower land prices in suburban areas, creating less inducement for public or private stakeholders to evict them.
• They may reflect past economic geographies, e.g., former industrial communities that have since moved to peri-urban areas.
• They may emerge in areas that were formerly middle class, as is occurring in some western countries today. 
• As energy prices increase, housing in urban nodes will rise in price faster than in suburban areas with limited employment and public transport access, resulting in possible disinvestment.
• Most central city slums are built at high densities – often between 600 and 1,800 people per hectare.
• The highest density slum in the world is Dharavi in Mumbai, home to over one million people (2003) living in an area of 175 hectares.
• Some informal communities feature formal, multistory apartment buildings where land and building ownership is clearly established. 
• In China, low-quality housing is frequently mid-rise, 6-8 story buildings built during the 1960s. 
• In some developing (and developed) country cities, housing built for the poor, either by the public sector (sometimes ironically to replace conventional slum housing) or by private developers, has deteriorated into slum conditions.
• Slums in the established, built-up areas of metropolitan systems mainly encroach on public lands (owned by government agencies, state enterprises, etc.). 
• State lands are often easy targets because of weak enforcement of land rights by public authorities and/or political motives, e.g., populist politicians may want to garner support from the poor. 
• In other cases, politicians may fear protests and violence related to lack of housing for the poor, particularly in-migrants.
• Another major location of slum communities in developing country cities are natural areas (officially protected or not), such as river banks, wetlands, steep slope land and public parks (e.g., in Dhaka). 
• Encroachment of slums on natural areas may increase environmental risks for themselves and for the city as a whole, by reducing land for environmental services. 
• As indicated above, slum dwellers generally try to locate on available land (i.e., where they will not be immediately evicted) that is most accessible to livelihood opportunities.

How to address difficulties in acquiring land for landfill operations?

Acquiring land suitable for urban landfills (such as transfer stations/zones, landfills, incinerators and/or composting plants) can be difficult, not only because of the special site requirements, which are related to geological stability, capacity, soil conditions, etc., but also due to “Not in My Backyard” (NIMBY) effects. 

NIMBY refers to sites commonly opposed to by people living in the immediate area of the proposed site and along the route that the waste transport trucks are expected to use.

Even well-managed landfills may produce odors and disease vectors, which lower the value of neighboring property and reinforce NIMBY effects. 

Poorly managed sites (and open dumps) pose additional health and environmental risks due to toxins leaching into the soil and water, and generation of hazardous gases. As a result, resistance to siting landfills near existing development is often intense. 

The result of this is lengthy travel times to landfills, increasing financial and energy costs and, once the distance exceeds certain limits, the need for transfer stations. Similarly, it is often difficult to acquire land for co-generation, recycling, composting, etc.

Hence, there are good practices which can be taken to understand  and implement to address the difficulties and problems.

1. Planning the location of solid waste treatment facilities based on regional environmental characteristics, including hydrology, geology, topography and predominant winds, as well as on functional considerations, such as volume, catchment areas and travel times. An important consideration in metropolitan areas is the possibility of sharing facilities among several municipalities, rather than each one building its own facility.
2. Including all stakeholders in land siting and design processes: Providing commitments to employing monitoring and community liaison staff from the community, and giving priority to local residents for new jobs created by the site, can help win site approval. Most cities also offer free unloading of wastes to the host community and/or a share of revenues obtained from tipping fees paid by users. Site designs that provide vegetative buffer zones, curved internal access roads that limit sight lines into the facility, and environmental mitigation measures that minimize emissions may further be included to secure public consensus.
3. Allowing temporary uses of vacant land for landfill operations: Dumping on vacant land should be strictly forbidden. However, allowing temporary uses of vacant land for landfill operations, such as composting, recycling or urban gardens, is an effective means to prevent unwanted/informal dumping in vacant lands. Proper pollution control measures should be adopted to avoid negative environmental impacts. After temporary uses, these lands could be redeveloped for other economic uses through certain cleanup and recycling techniques.
4. Encouraging community-based initiatives: Community participation in solid waste collection, siting and design of recycling, composting and co-generation facilities is inherently essential to sustainable solid waste management. Cities could create incentives for communities to undertake these function through providing public land and other innovative programs.
5. Allowing for on-site facilities: As waste is increasingly being seen as a new valuable resource and a symbol of green ethics, on-site facilities and yard space for domestic and industrial waste processing, such as composting and construction material recycling, should be encouraged,18 as should eco-industrial parks, where the waste of one industry is used as an input into another. Land use planning should allow for these activities, including landfill areas, which need to be larger than in the past to allow for co-generation facilities, methane gas capture and use, composting, recycling, etc.

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Land Readjustment

Land readjustment is a technique which pools land plots to enable redevelopment of large areas, giving existing plot owners a share of benefits in the re-plotted area. 

These benefits usually include both monetary benefits and a new housing unit. This very powerful tool shapes urban form, both in inner-city redevelopment areas and in peri-urban areas.

In peri-urban areas, it is particularly useful in shaping urban form where numerous small plots exist. It also enables public authorities and private developers to avoid piecemeal development, thereby enabling large-scale, and thus often more rational planning of transportation and settlement systems in areas of urban land conversion.

Although the conceptual elegance of this approach is clear, i.e., it enables win-win situations both for former land owners (who receive a share of the land appreciation through redevelopment, plus usually a housing unit) and the developers, it requires trust by land owners in the local authorities undertaking the process. 

Furthermore, it requires effective management, e.g., participants must be temporarily relocated until their new unit is ready for occupancy, and new accommodation/redevelopment needs to be delivered on schedule.

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What are the merits of urban service boundaries?

Urban service boundaries are effective in ensuring that new development does not impose an unreasonable financial burden on public sector services. 

Availability and cost of service delivery should inform which areas will be designated for new development and which uses will be permitted, in order to achieve more cost-effective and sustainable growth patterns. 

Ultimately, it can lead to better environmental infrastructure coverage in new areas on the fringe. Service boundaries also generally contribute to more equitable service costing. Without service boundaries, the majority of urban residents, especially those in inner city areas, subsidize service provision in leapfrogging peripheral communities.

Coordinating infrastructure plans with integrated land use and transportation planning offers additional advantages. 

Because utility corridors for water, sewage and other services generally run along road easements, installing trunk infrastructure ahead of road building reduces costs of road repair and traffic disruptions. 

However, just like other planning tools, enforcement is key for the success of applying service boundaries.