1. Increase in landslides, storm surge damage, etc. due to climate change
The Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) points out that there is no doubt about the warming of the climate system based on observations of temperature, sea surface temperature, sea level, and snow and ice loss. As a result of the emergence of extreme weather events due to the progress of climate change, there has been an increase in the intensity and frequency of torrential rains, extremely low pressure cyclones, and typhoons on a global scale, and it has become a common challenge for the world to take effective measures to deal with the increasing scale and frequency of slope disasters and the extensive damage caused by storm surges in coastal areas.
In recent years, land use change such as land conversion from forest to agricultural land in mountainous and coastal areas in developing countries has been progressing, which has aggravated the damage caused by climate change. Uncontrolled deforestation in mountainous areas and the opening of roads without consideration for drainage can destabilize slopes and trigger large-scale landslides. Once a landslide occurs, it can cause damage to farmland and houses, which are the means of livelihood for people living at the foot of the mountain, and in the worst case scenario, it can cause loss of life. In addition, the mangrove forest ecosystem in coastal areas not only mitigates the force of waves from the ocean, but the root system of the mangrove plants also serves as a seawall.
2. Importance of international cooperation in the field of disaster reduction through the Sendai Framework for Disaster Risk Reduction at the UN World Conference on Disaster Reduction
The Hyogo Framework for Action, adopted at the Second United Nations World Conference on Disaster Reduction in 2005, stated that disaster risk reduction is a cost-effective investment in preventing future losses, and that its management contributes to sustainable development. Based on this idea, not only local but also international efforts for disaster reduction were promoted. However, in the 10 years from 2005 to 2015, the global death toll from natural disasters was still 700,000 and the economic loss was over 1.3 trillion dollars.
The Third United Nations World Conference on Disaster Reduction (WCDR) in 2015 pointed out that the rate of increase in risk factors is much faster than the rate of decrease in vulnerability in all countries due to the recent increase in the scale and frequency of disasters caused by climate change. The Sendai Framework for Disaster Risk Reduction adopted at the conference aims to prevent new disaster risks and reduce existing disaster risks by preventing and reducing exposure to hazards and vulnerability to disasters, and to significantly reduce disaster losses in human lives and other economic and social assets of countries over the 15-year period from 2015 to 2030. In order to achieve this objective, it is particularly important to improve the capacity of developing countries to implement disaster reduction measures through financial and technical assistance through international cooperation.
One of the guiding principles of the Sendai Framework for Disaster Risk Reduction is the concept of "proactive disaster management," which is to deal with potential risk factors in advance. Pre-disaster management is considered to be more cost-effective than relying on post-disaster emergency response and recovery, and is a method that contributes to sustainable development, and has been emphasized in recent years in mountain reclamation projects in Japan. In March 2015, the Forestry Agency of Japan summarized its basic direction of disaster prevention measures as "Toward the Future Enhancement of Mountain Disaster Countermeasures”. The report noted that it is important to properly assess priorities based on the functions of the mountain and nature's recovery potential, and to select locations for implementation of erosion control projects and formulate erosion control project plans. This design concept of Japan's erosion control projects, which does not rely solely on hard measures, is expected to be applicable to erosion control in developing countries where financial conditions are limited.
3. Adaptation Measures in the Paris Agreement of the United Nations Framework Convention on Climate Change and Japan's Strategy for Exporting Infrastructure Systems
The Paris Agreement, adopted at the 21st session of the Conference of the Parties (COP21) to the United Nations Framework Convention on Climate Change (UNFCCC) in 2015 and entered into force in 2016, sets a goal of limiting the temperature rise to below 2°C, and as much as possible, below 1.5°C. The agreement also states that mitigation measures will be implemented through international cooperation. It also emphasizes the need to take adaptation measures to minimize the inevitable adverse effects of climate change. Article 7 of the agreement states that developed countries shall provide financial support to developing countries in relation to mitigation and adaptation, and that cooperation shall be strengthened to promote information sharing, the strengthening of institutional measures and scientific knowledge on adaptation. In addition, Article 9 states that countries may submit plans and reports on adaptation. Furthermore, Article 10 on the development and dissemination of science and technology and Article 11 on capacity building indicate the need to address both adaptation and mitigation. The COP21 decision also decided to set a new quantitative target for overall funding for mitigation and adaptation, with a lower limit of $100 billion per year, prior to 2025. It has agreed that the status of implementation (mitigation, adaptation, means of implementation, and support) will be periodically reviewed every five years starting in 2023 to assess overall progress toward achieving the long-term goal, and the results will be used as input for updating and expanding the actions and support of each country.
In Japan, the "Strategy for Exporting Infrastructure Systems" was revised in June 2019, and in this strategy, "guidance on mainstreaming disaster prevention and climate change countermeasures by utilizing Japan's experience and technology as an advanced disaster prevention country" is listed as one of the measures to expand infrastructure investment by utilizing Japan's technology and expertise. As a specific measure, the report states the need to promote support for the planning and implementation of adaptation measures to avoid and mitigate the damage caused by natural disasters in the Asia-Pacific region because the effects of climate change, which have become increasingly apparent in recent years.
4. The need for disaster prevention and mitigation by utilizing forest functions
There are many cases in the world where disasters occur frequently due to inappropriate land use of mountainous areas when a nation's economy growing rapidly. During the period of economic growth, industrial activities increase and the population grows rapidly, so traditional land use rules are neglected and land use is expanded to areas with high disaster risk, which tends to lead to more frequent disasters. In Japan, the increase in demand for wood and charcoal due to modernization during the Meiji era and reconstruction after World War II had led to excessive use of mountainous areas, resulting in frequent disasters. As a countermeasure, erosion control projects have been carried out in the vicinity of residential areas, mainly through the construction of concrete disaster prevention facilities. Since this technology utilizes the disaster mitigation function of the forest ecosystem, it is low cost and highly applicable to developing countries that are planning to implement full-scale disaster prevention measures in the future.
The development of forests in mountainous areas using erosion control technology reduces the risk of collapse, which in turn reduces the risk of disasters in downstream areas. In addition, the establishment and maintenance of disaster-resistant forests is another characteristic of erosion control technology. In this way, erosion control techniques can be used to reduce the risk of flooding. In this way, the disaster mitigation effects of forests developed with erosion control technology are extremely broad and diverse. In addition, in countries in Southeast Asia, where economic development has been remarkable in recent years, the number of people affected by floods is extremely high due to the high-rainfall events, and there is a concern that climate change will lead to large-scale flood damage. Forestation in mountainous areas using erosion control technology is expected to reduce sediment runoff from mountainous areas and mitigate flood damage caused by rising river beds, thus contributing greatly to comprehensive disaster prevention measures for the entire country, including flood damage. It is also expected to contribute to the mitigation of global warming through carbon fixation in forests.
While erosion control technology has such a wide range of advantages, it is a technical system that is difficult to demonstrate its effectiveness without appropriate land use planning, land use restrictions, and awareness-raising to improve disaster prevention and environmental awareness among residents. For example, even if a disaster prevention forest is established around a residential area, if there is no appropriate land use restriction, private use may be left unattended, leading to the destruction of the forest. This is the so-called tragedy of the commons. However, in today's world where the SDGs (Sustainable Development Goals) are emphasized, the characteristic of erosion control technology that requires such land use planning and environmental education can be an advantage for increasing disaster prevention awareness among the residents.
Particularly in disaster-prone region such as monsoon Asia, land use restrictions may limit economic activities local people for short term, but it is certain to lead to the safety of the people for long term. In Japan, there are many cases where it has been pointed out that the development of residential areas in areas with high disaster risk resulted to suffer disasters. In developing countries where disaster prevention and mitigation measures are being formulated, it is essential to develop erosion control technologies with proper land use plans and awareness raising for disaster prevention. The early introduction of disaster prevention and mitigation function assessment and conservation measures for coastal areas against storm surge damage and deepening awareness of the disaster risks of land will lead to a reduction in disaster prevention budgets and stabilization of people's livelihoods in the future, and is considered to be extremely cost effective in terms of investment in the future.
For effective zoning with a consensus between the government and the people, it is necessary to assess the disaster risk of the land as accurately as possible based on scientific knowledge and to inform the people in a prompt and effective manner. In order to do this, it is essential to utilize information technology, which has developed rapidly in recent years, based on an understanding of local ecosystems and social and cultural backgrounds, and in particular, it is expected that zoning technology can be upgraded by introducing remote sensing and AI technology. Our research aims to contribute to the implementation of disaster prevention technologies utilizing the disaster prevention and mitigation functions of forests in developing countries by combining the latest information technologies, such as remote sensing and AI, with the mountain disaster prediction technologies that have been accumulated as Japanese mountain management technologies.