In the first chapter of this treatise, John Locke argues that Adam was not actually given authority over the earth. Moreover, he claims that the notion of Adamic authority passing down to his heirs depends on being able to identify the heirs of Adam, but we cannot do so. Although this does not provide a clear pro-environmental argument, it can be used to counter the argument advanced by some evangelical Christians that as Adam's heirs we have an absolute right to do anything we wish to the earth and the animals living on it.
Next, we have the argument that rulers rule with the consent of the ruled. When we look at environmental issues such as habitat destruction and ensuing species extinction, we can argue that (given recent evidence that certain animals think and feel) we have no right to kill animals and destroy their habitat without their consent.
We can also look at environmental issues in terms of the right to private property. Locke argues that the natural rights of one person to act as he wishes end when such actions impinge upon the property or freedoms of other people. Damage to any part of the global environment can affect many other parts. For example, global climate change and rising sea levels may actually submerge inhabited low-lying islands such as Kiribati. If the private property of individuals is damaged or destroyed by the carbon emissions of certain other people, that infringes on property rights.