Use of wood to prevent global warming

According to documents from the Forestry Agency, Japan's forest resources are increasing year by year, with annual growth of approximately 80 million ^m2, while the domestic supply of timber is approximately 20 million ^m2, leaving a huge surplus. Japan, which is said to be a resource-poor country, has no choice but to utilize these precious, unused resources.

Local governments have also begun to take steps to promote the use of wood. In Tokyo's Minato Ward, the "Promotion Policy for the Use of Agreement Wood" (agreement wood: wood produced by local governments that have signed agreements with Minato Ward to promote the use of domestic wood, including thinned wood) was established two years ago, and the ward has begun to actively use wood in public facilities. The use of agreement wood is also encouraged for buildings over ^{5,000 m2}. The goal is to use ^{0.005 m2} per 1 ^m2 of floor space, so for a building with a floor space of 10,000 ^m2, the amount of wood used will be 50 ^m2. Since the amount of wood used in an average wooden house (120 ^m2) is about 25 ^m2, this is equivalent to the amount used in two houses. Wood is currently used for some of the interior materials and fittings, but if the Building Standards Act is revised to allow wood to be used as a structural material, it is expected that it will also be used in places other than housing.

Currently, various energy-saving and CO2-reducing efforts are being made at construction sites. Using wood fixes CO2. Furthermore, wood reproduction leads to the absorption and reduction of CO2, and is also expected to contribute to the revitalization of Japan's forestry industry, with significant ripple effects.

At the end of March this year, the 38th General Assembly of the Intergovernmental Panel on Climate Change (IPCC) was held in Yokohama, and the Fifth Assessment Report and the Working Group II Report (Impacts, Adaptation, and Vulnerability) of the IPCC were published. The report showed that the impacts of global warming have been observed over a wide area, and described the impacts on each region of the world, as well as the impacts on food, water, ecosystems, etc. IPCC Chair Pachauri stated, "There is no one on Earth who is not affected by global warming. If we do nothing, the damage will spread and the possibility of irreversible impacts will increase." In addition, the First Working Group Report (Natural Science Basis) issued last fall showed that the temperature rise between 2016 and 2035 is likely to be between 0.3 and 0.7 degrees. It also stated that "If global warming progresses more quickly and significantly in the future, it may exceed the limits of adaptation, but by taking effective adaptation measures and promoting mitigation measures through changes in political, social, economic, and technological systems, the realization of a resilient society and sustainable development will be promoted." The only way to address the predicted risks at present is to limit the rate and magnitude of climate change.

Greenhouse gas emissions in Japan have been on the rise recently. Compared to the base year of the Kyoto Protocol, emissions fell by 4.4% in 2009 after the Lehman Shock, but increased by 6.5% to 1,343 million tons in 2012. Breaking it down, emissions from the industrial and transport sectors are on a downward trend, but emissions from the commercial and residential sectors have increased by around 50% compared to the base year (Ministry of the Environment, "Calculation Results of Japan's Greenhouse Gas Emissions"). These two sectors are the areas that we Architectural Design are primarily involved in.

The use of wood may be more of a mitigation measure than an effective response, but it is important to work to extend the lifespan of buildings and take measures to reduce CO2 emissions over the life cycle of buildings, including the use of wood, since the amount of CO2 reduction will vary greatly depending on the approach taken at Architectural Design stage.