Satellite‐based precipitation estimations provide frequent, large‐scale measurements. Deep learning has recently shown significant potential for improving estimation accuracy. Most studies have employed a two‐stage framework, which is a sequential architecture of a rain/no‐rain binary classification task followed by a rain rate regression task. This study proposes a novel precipitation retrieval framework in which these two tasks are simultaneously trained using multi‐task learning approach (MTL). Furthermore, a novel network architecture and loss function were designed to reap the benefits of MTL. The proposed two‐task model successfully achieved a better performance than the conventional single‐task model possibly due to efficient knowledge transfer between tasks. Furthermore, the product intercomparison showed that our product outperformed existing products in rain rate retrieval and also yielded better skills in the rain/no‐rain retrieval task.

The international community has agreed through the Paris Agreement to limit the global temperature rise to less than 2 °C above the pre-industrial level. In recent years, many targets with carbon-neutrality as the keyword have been announced. The realization of carbon-neutrality is much more ambitious than the Kyoto Protocol-based climate change countermeasures, and will necessitate major shifts in social structure. Nevertheless, even economic organizations organized by corporations have been announcing that they will cooperate with carbon-neutral goals rather than oppose them. This study investigates the past trends by particularly addressing on the progress of climate science, the economic policies of various countries, the efforts of corporations and investors, and the activities of NGOs, etc. Furthermore, this study clarifies the background to elucidate why the world is moving toward carbonneutrality from a broad perspective. The literature review confirmed that climate science progress has influenced the international agreement, and that development of new countermeasures such as TCFD, which requests private enterprises to open their climate risk information, has encouraged the carbon-neutral movement. In the private sector, climate risk reduction and economic benefits are linked through TCFD, suggesting a paradigm shift in the awareness of the parties involved that climate change measures are "no longer a social contribution but are necessary for their own survival". Along with the supports of these changes in social conditions, the international community is thought to have moved toward carbon-neutrality.