How long can the Earth System sustain the present rate of human-induced global-environmental change?

Humans are modifying the planet at an alarming rate. Cropland and pasture now cover almost 50% of the entire land surface. This has led to massive habitat destruction, fragmentation and pollution and, together with overhunting, is causing a critical loss in biodiversity. Agricultural pollution is also having a devastating impact on aquatic and marine ecosystems which, together with industrial fishing, is causing collapse of key species populations within these ecosystems. Industrial pollution and burning hydrocarbons is causing polar warming which threatens to destabilize the remaining ice-sheets and reservoirs of methane stored in the polar oceans and permafrost. With populations in the US, China and India still rising, these clearly unsustainable practices are set to continue. The critical question is how long can planetary environmental processes continue to function before these human-induced changes trigger negative feedbacks that result in a switch to an alternate and less supportive Earth System state?

5 comments

1. Manuela Bassoi says:

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   I agree with some comments, unfortunately this is not a question that we are able to answer.
2. Kalense says:

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   The short version of the question “How long can the Earth System sustain the present rate of human-induced global-environmental change?” makes no sense to me. To explain why, let’s get rid of the adjectives: “How long can the Earth sustain the present rate of change?” If it’s changing, it isn’t sustaining, by definition.

   The question “how long can planetary environmental processes continue to function before these human-induced changes trigger negative feedbacks that result in a switch to an alternate and less supportive Earth System state?” is entirely different. But it is also wrongly formulated, because what we should fear are positive, not negative feedback processes.

   Furthermore, it is a purely rhetorical question, that is, not a question that we can answer. We do not know enough about how Gaia works, and cannot do the experiment in vitro. It would be pointless to invest money in research to try to answer this question.
3. Alura says:

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   The Earth System is the self-regulated system, we can only predict, forecast and try to mitigate the situation related with human-induced global-environmental change, but the precise assessment on “How long can the system sustain” can not be done.
4. anilgb says:

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   this is extremely critical question and can not be avoided any more
5. dansat says:

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   This is to me the pressing question above all others.