decreased from $ 30^{\circ} $ C to $ 15^{\circ} $ C during daytime and its emissions after sunset was almost zero, reaching around $ 0^{\circ} $ C (Figure3-3-12). That means, the city block has very little accumulation of heat at night that could cause the heat island phenomenon. Not only introducing highly efficient equipment, but also examining the structure of the city is important for energy saving measures from the long-term perspective.

(B) Community development aiming to reduce greenhouse gas emissions

Looking at the approaches aimed at reducing GHG emissions, developed in actual communities, it is especially important not only to urge each relevant approach, but also to pursue collaboration and cooperation of those involved led by local governments, in community development where the region as a whole makes efforts. Achievement of environmental targets, which the region share, will progress as projected with this, and regional vitalization can be expected at the same time.

a Consideration of community development in regions

—Community development of Iidabashi Station West Exit area, which incorporates target of reducing $ CO_{2} $ emission intensity—

Chiyoda ward in Tokyo established the “Chiyoda ward global warming mitigation ordinance” in December 2007, and set a mid-term goal to reduce $ CO_{2} $ emissions within the ward by 25% by 2020 compared to 1990. The ward is to accomplish this goal by intensively focusing on energy savings measures in existing small and medium buildings, area measures on city blocks and areas and to promote the introduction of renewable energy, in addition to measures by electric power companies to reduce $ CO_{2} $ emissions intensity. Especially, strategies to stock green energy—utilizing know-how of large corporations, such as energy saving methods and information on their cost-benefits to small and medium buildings—should be deployed, in order to advance energy savings in existing buildings. The ward was selected as an eco-friendly model city by the Regional Revitalization Bureau Cabinet Secretariat in January 2009.

In March 2009, the ward formulated and announced the eco-model city action plan to achieve the target of reducing GHG emissions as an eco-friendly model city, by 25% by 2020, and 50% by 2050, compared to 1990.

In 2008, the Law Concerning the Promotion of the Measures to Cope with Global Warming was revised. The revised law stipulated that prefectures, designated cities, core cities and special cities should establish items related to the measures to curb GHG emissions as needed in the Action plans of local governments, depending on the area's natural and social conditions. Regarding the measures related to curb GHG emissions of city plans and others, the governments were made to take GHG emission curb in collaboration with the Action plans of local governments into account, while balancing with the achievement of goals of such measures. Other municipalities are also expected to reduce GHG emissions in collaboration with the Action plans of local governments and others.

Iidabashi Station West Exit area of Chiyoda ward is located in front of Iidabashi station and is one of the most important transportation hubs in the urban center where five railroads converge, and is an area where new businesses and residential functions are accumulating. The ward is aiming to develop the infrastructures of this area in order to improve its attractiveness, and has agreed upon the "Iidabashi Station West Exit Area Development Project" based on the City

Planning Act (Act No.100 of 1968) in June 2008.

In the project, the energy savings and $ CO_{2} $ reduction in buildings, and total reduction of environmental load in collaboration with buildings in the region should be progressed as the approach driving the measures against global warming of the entire ward. The plan is also aiming to promote environmental measures in collaboration with surrounding areas.

In addition, when the building functions are renewed during the redevelopment of Iidabashi Station West Exit area in the future, under protection ordinance against global warming, eco-model city action plans and Iidabashi Station West Exit Area Development Project, the Chiyoda ward will streamline energy use, while promoting approaches towards improving the environment, such as appropriate use of resources systematically. Especially, the project stipulates that the average $ CO_{2} $ intensity within the area to be less than 60% of those related to the operational division in the ward in principle.

As for energy-saving measures, the ward will implement heat load reduction by using super insulating glass and using energy-saving lighting, as well as implementing greening and water retention pavements in the area. The reduction of $ CO_{2} $ intensity in the above business division are to be realized, and in 2012, although expecting the increase of total square meters of building floor area, due to the mitigation of floor-area ratio, the ward is aiming to contain the increase of the total $ CO_{2} $ emissions from buildings in the area to within 5% of current levels.

Furthermore, Chiyoda ward is seeking to keep collaborate with businesses, aiming to reduce the total amount of $ CO_{2} $ emissions from buildings in the area by about 25% in 2020, compared to the 1990 level. Other intended measures are as follows: the use of heat waste in surrounding areas which was produced within the area; the use of electricity in the area which was generated with solar power generation devices, intensively installed in surrounding areas; the introduction of an area energy management system, which will collect the energy consumption data of the buildings within the area and surroundings by computer systems, and then specialists will give energy-saving advice, based on the collected data.

b Redevelopment of old factory sites, in cooperation with private developers and city hall

—Redevelopment of Settsu city’s Minamisenrioka area, aiming to reduce $ CO_{2} $ emissions and the heat island load at night—

In Settsu city, Osaka prefecture, a trilateral agreement called “The memorandum of Minamisenrioka community building, a model area against global warming” was concluded between a private railroad company, which will establish the new station, a private business, which proposed community development on introducing private revitalization, and city hall. In order to realize countermeasures against global warming, the parties concerned are advancing community development through cooperation. The area aims to reduce the amount of $ CO_{2} $ emissions by 25% by around spring of 2013, at the time of the opening of the community, compared to the current estimated $ CO_{2} $ volume on the assumption that average residential and business facilities in the Osaka area will be as simulated (Figure3-3-15). As for the countermeasures against heat island, the city is aiming to reduce heat load by $ 12W/m^{2} $ at night.

As for the approaches towards achieving the target, the following are planned: private businesses to replace