〜Contributing to the creation of Japan’s first rice paddy J-Credits with added value related to biodiversity〜
Green Carbon Inc. (CEO: Jun Okita, hereinafter “Green Carbon”), which develops a nature-based carbon credit generation and sales business, has announced that it has visualised the impact of Osaka Gas Co., Ltd. (President: Masataka Fujiwara, hereinafter referred to as Osaka Gas) extended midseason drainage period for paddy fields (※1) (※2) to reduce methane emissions, a greenhouse gas. This was achieved through a biodiversity impact survey using Environmental DNA (※3).
This enables the extension of the midseason drainage period in paddy fields to become a high-value J-Credit scheme for paddy fields, which not only reduces emissions but also avoids adverse impacts on the biodiversity of the surrounding environment. The value derived from these survey findings will be added to the J-Credits scheduled for issuance in 2026, generated through the extended midseason drainage period.
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〇To download Green Carbon Co., Ltd.’s company profile, please visit
◆ Background
Green Carbon is engaged in creating nature-based carbon credits, primarily in Southeast Asia, operating across diverse sectors including forest conservation, rice paddies, mangrove afforestation, cattle methane reduction, and biochar projects. The company develops projects suited to each region’s natural resources, utilising satellite data for site selection and monitoring to achieve efficient and highly transparent operations. Its rice paddy projects, in particular, are being implemented on a large scale both domestically and internationally.
Amidst this context, the reduction of methane emissions through extending the midseason drainage period of paddy fields was approved as a methodology under the J-Credit system in 2023. Since then, the volume of paddy field J-Credits issued has been increasing, and it is anticipated that this will rise to account for approximately 30–40 per cent of total J-Credit issuance going forward (※4).
In Japanese rice cultivation, midseason drainage of paddy fields is generally practised. However, concerns have been raised that extending this drying period to reduce methane emissions creates an environment differing from conventional practices, potentially impacting the ecosystems inhabiting these fields. It is therefore necessary not only to realise the positive effects of reducing methane emissions from paddy fields but also to resolve and minimise the risks to biodiversity.
Green Carbon therefore partnered with Osaka Gas, which possesses expertise in assessing biodiversity in paddy fields, to commence a study in June 2025 investigating the impact of extending the midseason drainage period on biodiversity. This project involves collecting and analysing water level data (paddy field water) from the target paddy fields both before and after implementing midseason drainage. By comparing biodiversity lists before and after the midseason drainage period, it enables analysis of ecosystem information and impacts on biodiversity, facilitating the prioritisation of conservation activities and the verification of environmental policy effectiveness.
◆ Survey Overview
In the biodiversity impact assessment, water samples were collected from paddy fields in four prefectures where Green Carbon implemented extended midseason drainage periods. Osaka Gas analysed trace genetic material (environmental DNA) from organisms inhabiting these fields, such as dragonflies and frogs, to evaluate the impact on biodiversity. Similar assessments are currently underway in paddy fields in other prefectures.
By comparing species present before and after the implementation and extension of midseason drainage , it is possible to analyse impacts on ecosystem information and biodiversity, thereby enabling the prioritisation of conservation activities and the verification of environmental policy effectiveness.
◆ Future Initiatives
The biodiversity value visualised through this survey will be added to J-Credits generated by the extended midseason drainage period, scheduled for issuance around spring 2026, and sold through Green Carbon. By making the impact on organisms visible, customers will be able to understand the environmental value and trade J-Credits with confidence.
We shall disseminate information on biodiversity survey and assessment methods through seminars and similar events, whilst also commencing advance sales of the high-value-added paddy field J-Credits slated for creation.
Moving forward, we will expand the scope of verification and conduct detailed investigations to create high-quality credits. Concurrently, we will establish a mechanism to enhance supplementary income for farmers undertaking biodiversity surveys. Through further detailed analysis and broadening the scope of investigations, we aim to provide information better aligned with needs while expanding the range of J-Credits available.
○Paddy Field Consortium：https://inasakuconsortium.com/
※1：midseason drainage
A practice during rice cultivation where the paddy field is drained once before heading to dry the soil surface, thereby preventing excessive tillering (branching near the base) and controlling growth.
※2：extended midseason drainage period for paddy fields
A methodology for reducing methane emissions approved under the J-Credit scheme. As flooded paddy fields generally produce methane readily, extending the midseason drainage period—commonly practised in rice cultivation—by seven days has been confirmed to reduce methane emissions by 30%.
※３：Environmental DNA
A general term for DNA released into the environment, such as water, soil, or the atmosphere.
※4：it is anticipated that this will rise to account for approximately 30–40 per cent of total J-Credit issuance going forward
Estimated from the project proposals of each company published in the J-Credit registry
◆ Green Carbon ,Inc.
Representative: Jun Okita, CEO
Head Office: PREX North 9F, 2-3-2 Kojimachi, Chiyoda-ku, Tokyo, Japan
Established: December 2019
Business Activities: Development and sales of carbon credits, agriculture-related projects, environmental projects, other related businesses, and ESG consulting
Website: https://green-carbon.co.jp/en/
◆Osaka Gas Co., Ltd.
Representative：Masataka Fujiwara, President
Head Office：4-1-2 Hiranomachi, Chuo-ku, Osaka 541-0046, Japan
Established：April 10, 1897
Business Activities：Manufacture and sale of gas, generation and sale of electricity, etc.
Website： https://www.daigasgroup.com/
◆Osaka Gas Business Overview
The Daigas Group, under its “Energy Transition 2050” strategy announced in February 2025, is committed to developing technologies and services that contribute to a decarbonised society. They strive to address societal challenges, including climate change, and aim to remain a corporate group that supports the “further evolution” of both daily life and business.
◆ About Green Carbon
Guided by the vision of “Harnessing the power of life to save the Earth,” Green Carbon develops and supports projects that generate, register, and sell nature-based carbon credits both in Japan and abroad. The company is also engaged in agriculture-related businesses, R&D initiatives, and ESG consulting.
Its business activities span Japan, Southeast Asia, Australia, and South America, creating credits from rice paddies, biochar, forest conservation, carbon farming, mangrove planting, and cattle methane reduction. In Japan, Green Carbon obtained certification in FY2023 for the country’s first and one of the largest-scale rice paddy J-Credit projects (approx. 6,220 t). In FY2024, the company plans to expand this initiative to around 40,000 ha (approx. 80,000 t).
Green Carbon also provides “Agreen,” a one-stop platform service that streamlines the entire process of credit registration, application, and sales. By simplifying procedures and documentation, the service reduces the administrative burden on credit creators.
◆Green Carbon’s social media
Youtube ：https://www.youtube.com/channel/UCYO4WnGOHDaVB1ikxheZasA
note ：https://note.com/green_carbon/
Facebook：https://www.facebook.com/profile.php?id=61557429326458
X ：https://mobile.x.com/GreenCarbon2019
Linkedin ：https://www.linkedin.com/company/green-carbon-inc/
Wantedly：https://www.wantedly.com/companies/greencarbon2019