'Protecting Forests: Are Early Warning Systems Effective?' A Blog on Brookings's Website

A blog entitled “Protecting forests: Are early warning systems effective?” written by Yamada Eiji (research fellow at the JICA Ogata Sadako Research Institute for Peace and Development), Okonogi Hiroaki (special advisor to the Global Environment Department at JICA), and Morita Takahiro (chief representative of the JICA Thailand Office) was published on the Brookings Institution’s website on July 2, 2021.

In the blog, Yamada and colleagues stated that early detection is a critical element of efforts for deforestation control, where artificial satellites play a crucial role. To monitor deforestation, tropical countries widely use several early warning systems by using regularly updated optical satellite data, which capture the reflection of sunlight from the ground surface. However, the authors pointed out that optical satellite data pose an inherent shortcoming, that is, detecting deforestation using optical satellites is difficult during the rainy season, when cloud coverage is high. They argued that this aspect is a serious problem because the majority of illegal destruction occurs during the rainy season to avoid detection, especially in the Brazilian Amazon.

As a solution, they proposed the use of “radar eyes” in place of “optical eyes.” The underlying reason is that radar waves can penetrate through thick clouds, which makes earth's surface visible regardless of cloud coverage. Moreover, radar satellites are equipped to capture images of the earth’s surface by catching the reflection of radar waves generated by the satellite itself. Moreover, they stated that Japan’s Advanced Land Observing Satellite-2 or ALOS-2 radar satellite, for instance, can detect 1.5 to 10 times more deforestation than optical satellites can during the rainy season in the Amazon area. Furthermore, the blog conducts a quantitative investigation to demonstrate the effectiveness of radar satellites as a preventive and mitigating measure against illegal deforestation.

Click the link below to read the full blog post.