In bygone days, the environmental movement would often cast its lot with a "Save the [blank]" ideology that generally included non-human components such as "world" or "whales" or "spotted owls" in its formulation. Unsurprisingly, many people scoffed at the suggestion that human opportunities and progress should be foregone in the name of saving other entities. In the end, the notion that our existence might somehow be dependent upon the existence of those "other" things -- or that we ought to learn to get by with less of the stuff we wanted -- was a hard sell to a public used to thinking in Cartesian terms of separation and one that is deeply inculcated with a cultural mythos of human superiority. Simply put, this way of getting at the issue actually fostered the very sense of a "humans versus nature" rift that underlain the problem in the first place.
Today, however, the rhetorical tide has shifted even as the oceanic one has threatened to rise. Now the pitch is more akin to "Save the Humans," since it's our own vulnerable and somewhat maladapted arses that are on the line at this point. It was sheer hubris to believe that the world itself needed saving from human interventions; the Earth and its life-giving capacities are resilient and will almost certainly (at least on a geological time scale) survive whatever we throw at it short of total nuclear pulverization. In fact, many other life forms would flourish without us here, with Nature rapidly re-wilding even the concrete jungles we've created. So it's really about saving ourselves these days, which is a more realistic aim and one that is consistent with our actual place in the web of life.
It's also an easier sell for most people. Advocating for the preservation of a seemingly unimportant animal species as against many human jobs and their families' wellbeing is not particularly persuasive, as spotted owl advocates found out some years ago (even today, I still see faded bumper stickers saying "Spotted Owl Tastes Like Chicken"). A much more potent argument is that those same loggers would be put out of work by deforestation and the clear-cutting of old growth stands, since they rely on the renewal of the resource in order to have continuous employment in their region. Indeed, this logic -- human engagement with the environment in the context of renewal capacities -- can be a powerful avenue for sustainability advocacy to address both human and nonhuman needs.
Let me illustrate the point clearly, and briefly. I recently asked some of my students whether water was a scarce or abundant resource. Being good environmentalists, they mostly reflected upon the hard-to-deny fact that water is scarce and getting scarcer -- it's the "new oil" and "blue gold" as various outlets continually suggest. There's a truth in this perspective, and yet water can also be seen as an abundant resource in which the planet's evaporation-rainfall cycle continually renews it. We can actually quantify the amount of water it takes to maintain a local aquifer or the flow of a river at healthy levels, and this is sometimes known as the "recharge rate" of how much it would be necessary to put back in to keep the water flowing. Swimming pool owners in hot climates, for example, often fill their pools a little bit each morning to compensate for evaporation, and thus perform a low-tech version of recharging their water levels in this manner.
In fact, every resource has an inherent recharge rate , in the sense that the "balance of a system can be expressed as a relationship relating all of the inputs and outputs into or out of the system." Water is perhaps the easiest to measure, as in the swimming pool example, although in the real world variables such as soil moisture levels and the location of stormwater basins can make the calculations somewhat more complex. Still, rates are estimable if not outright calculable in most locales, suggesting that in practice we can find the balance point between output (i.e., what we consume) and input (i.e., what gets replaced) for any given resource. Using this framework, the distinction between renewable and nonrenewable resources become blurred, since everything has an inherent (or at least potential) rate of renewal and can thus be sustained over time.
This may seem counterintuitive, since we've been accustomed to viewing resources like oil and minerals as nonrenewable, but that's only because we've applied a human time scale to such commodities. The planet might in fact produce more of them, although it could take millions or even billions of years. The resources that take the longest time to replenish are also among the most costly to extract and likewise oftentimes contribute most directly to the problems of pollution and climate change that we presently face; furthermore, we can't claim to fully understand what the consequences would be if they were completely depleted in rapid fashion as we are seemingly aiming toward. Resources like air and water that have faster recharge rates are among the most basic for survival and are also the most vulnerable to disruptions in their renewal cycles. Food sources recharge fairly quickly as well, as do soils for growing, although less so than air and water; timber resources take a bit longer but can still renew within human time spans.
So here's my recommendation for sustaining the planet's fecundity, and for saving ourselves in the process: consumption within recharge rates, but no more. Air, water, and food are abundant and renew quickly, and thus can be consumed at significant levels. Coal, oil, uranium, and natural gas recharge very slowly and therefore should only be consumed at very small levels (if at all) consistent with how long it would likely take to replace them. Trees might still be used for human purposes, but only as fast as they will grow back or can be replanted. Solar radiation, geothermal energy, wind power, and tidal cycles renew continually, and their recharge rates are internally driven, so they can be utilized widely and abundantly.
Thich Nhat Hanh refers to something very much like this as "mindful consumption," which he contrasts with the unmindful practices that are "doing violence to our home" and have led the world to the doorstep of "catastrophic climate changes," yielding a pervasive sense of "violence, hate, discrimination, and despair." In his moving book The World We Have, Hanh illustrates the potential for positive alternatives with the story of "the vessel of appropriate measure":
"Since the bowl is exactly the right size, we always know just how much to eat. We never overeat, because overeating brings sickness to our bodies.... We see that people who consume less are healthier and more joyful, and that those who consume a lot may suffer very deeply.... Mindful consumption brings about health and healing, for ourselves and for our planet."
Obviously we must consume in order to survive, but if we do so outside the bounds of an "appropriate measure" our survival is placed in grave jeopardy. If someone who is cold burns down an orchard to stay warm for a night, they will likely have to cope with hunger the next day; in this manner humanity often seems to find itself cascading from one crisis to the next, as each quick-fix intervention leads to a new (and perhaps more intractable) problem. People inclined to get rankled over any sentiment that encourages us to do with a bit less of some particular item might consider what it would be like if we were forced to try and survive with less (or none at all) of everything, which may be in store if we fail to act. Consuming within recharge rates is a way to ensure not only our short-term but also our long-range existence on this remarkable, self-renewing world that sustains us.