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After the Buddha passed away, his teachings were compiled into a large collection of scripture called the Tipitaka, which is regarded as canonical by all Buddhists.
The first precept of Buddhist ethics is to not kill any living creature. The explanation goes beyond merely not harming, to being full of compassion for all beings (e.g. Brahmajala Sutta, D?gha Nik?ya 1.1.8). This demonstrates how Buddhist ethics are not just concerned with how we treat other humans. Humanity is always considered as embodied in our environmental context.
The Aggañña Sutta (D?gha Nik?ya 27) and the Cakkavatti S?han?da Sutta (D?gha Nik?ya 26) illustrate this through a cosmological myth of origin and evolution. At each stage, human greed causes the environment to decline, forcing our own evolution in response. Social contract, organized democracy, and the defining of land ownership all emerge from our abuse of scarce resources, to manage the increasingly difficult environmental situation. Things escalate, and stress, punishment, violence and war emerge – ultimately leading to total social breakdown. Eventually, the chaos is redeemed and society is rebuilt, but only when human beings realize their essential ethical duty, starting with the first precept: not to kill any living being.
Like any cosmology, the historical details of this story should not be taken too literally. But these discourses present a remarkable understanding of humanity’s role in creating environmental problems, and our duty to help redress them.