Cities and Biodiversity Outlook
Urban ecosystem services and biodiversity can help contribute to climate-change mitigation and adaptation

Urban green spaces, ranging from parks and agriculture to residential lawns and roof gardens, can contribute to climate-change mitigation.

Cities contribute 60—70 percent of global greenhouse gas emissions. Therefore, by investing in urban biodiversity and ecosystem services, cities can play important roles in mitigating and adapting to climate change. Green spaces can increase carbon storage and uptake, as well as significantly reduce the urban heat island effect. Trees can also contribute indirectly to climate-change mitigation by providing more shade and cooling, thereby reducing overall energy consumption.

Blue spaces, such as functional watersheds, also play a crucial role in mitigating and adapting to climate change. Watersheds provide access to safe water for drinking and irrigation, which is especially critical given how climate change is disrupting precipitation cycles, historical river flows and groundwater levels. Preserving rather than draining and paving over wetlands can allow for the absorption of excess rainfall and buffer against coastal flooding.

AICHI TARGET 15: By 2020, ecosystem resilience and the contribution of biodiversity to carbon stocks has been enhanced, through conservation and restoration, including restoration of at least 15 per cent of degraded ecosystems, thereby contributing to climate change mitigation and adaptation and to combating desertification. No other level of government does as much restoration as local governments. Many "brown" and transition (ex-industrial) areas under city governments are either in the process of being restored or could be. City governments can also promote the use of green infrastructure and roofing.

Mitigating Local Climate Change in Yokohama
In 2007 the administrative district of Yokohama, Japan, emitted almost 20 million tons of CO2. Aiming to become a low-carbon city, it set a goal to reduce CO2 emissions per person by at least 60 percent, relative to the 2004 level, by 2050. With a population of almost 3.7 million, Yokohama has been continuously degrading and converting its forests and farmland. The consequence has been a demonstrable impact on the city's microclimate, above that associated with global climate change, resulting in an urban heat island effect. The increase in buildings and paved surfaces has enhanced the city's heat-absorption capacity and increased its reflective heat, thereby raising temperatures. At the same time, the decrease in forests and farmland has reduced evapotranspiration, thereby slowing cooling. Recognizing the importance of biodiversity in stabilizing the local climate, the city introduced a new tax system and a mechanism to use the revenue to conserve privately owned green areas. It also decided to expand green areas with rooftop and wall greening and to work with citizens to reduce residential CO2 emissions. It set a minimum target for effective evapotranspiration from green areas at 30 percent of the total city land area.

Action on Climate Change in Mexico City
Mexico City was the first Latin America city to implement a Climate Action Program. Three components of the overall program place biodiversity at their core: (1) The Green Roof Program aims to create 10,000 square meters of new green roofs annually, to improve air quality, regulate humidity, reduce temperatures, and provide new biodiversity resources across the city. By increasing environmental awareness among citizens, the program also plays an important educational role. (2) Focusing on pollution risks, the Recovery of the Rivers Magdalene and Eslava program is improving environmental conditions in two important tributaries and their surrounding neighborhoods. Additional funding in 2011- 2012 helped secure a water supply for the city and reduce the energy and economic costs associated with traditional water treatment. (3) Almost 60 percent of Mexico City is represented by Land for Conservation, which provides environmental goods and services essential to the entire city. The two-pronged Program of Restoration of Ecosystems and Compensation for Maintaining Environmental Services rewards landowners in this area both for protecting essential natural resources and for restoring degraded habitats. It also encourages communities to actively protect and restore natural ecosystems.

Image source: Jocelyn Augustino, FEMA Photolibrary

The World with a Global Temperature Rise of 4°C

Figure 1: The World with a Global Temperature Rise of 4°C
In order to understand more about what the human impact of high-end climate change might the Met Office Hadley Centre has produced a map outlining some of the impacts that may occur if the global average temperature rises by 4 °C (7 °F) above the pre-industrial climate average.
Although the average temperature rise over the globe is 4 °C (7 °F) the projection on the map shows that this average rise will not be spread uniformly across the globe. The land will heat up more quickly than the sea, and high latitudes, particularly the Arctic, will have larger temperature increases. The average land temperature will be 5.5 °C above pre-industrial levels.
The map was produced by the Met Office (on behalf of HM Government), but contains contributions from climate scientists from other institutions conducting the latest research on climate impacts.
Source: Met Office

Global Cyclone Hazards

Figure 2: Global Cyclone Hazards
The relative distribution and frequency of global cyclone hazard.
Source: NASA-CIESIN-SEDAC

Global Drought Hazards

Figure 3: Global Drought Hazards
The relative distribution and frequency of global drought hazard.
Source: NASA-CIESIN-SEDAC

Global Flood Hazards

Figure 4: Global Flood Hazards
Relative distribution and frequency of global flood hazard.
Source: NASA-CIESIN-SEDAC

Annual Mean Surface Temperature

Figure 5: Annual Mean Surface Temperature
Annual mean surface temperature from the atmospheric component of GFDL-CM3 (historical and RCP8.5 experiments) spanning 1860 to 2100. Temperatures are contoured to smooth grid cell edges.
Source: Earth System Grid CMIP5 repository

Yokohama

Figure 6: Yokohama
In 2007 the administrative district of Yokohama, Japan, emitted almost 20 million tons of CO2. Aiming to become a low-carbon city, it set a goal to reduce CO2 emissions per person by at least 60 percent, relative to the 2004 level, by 2050. With a population of almost 3.7 million, Yokohama has been continuously degrading and converting its forests and farmland. The consequence has been a demonstrable impact on the city's microclimate, above that associated with global climate change, resulting in an urban heat island effect. The increase in buildings and paved surfaces has enhanced the city's heat-absorption capacity and increased its reflective heat, thereby raising temperatures.
Photo: Digital Globe / Google Earth

Sea Level Vulnerability

Figure 7: Sea Level Vulnerability
Sea Level Vulnerability