In my late teens I went on holiday with a friend to Devon (in south-west England), where, on a beautiful sunny day, we settled ourselves down on a large rock and watched as the tide came in around us, cutting us off from the shore. We were deliberately courting a little adventure. When the tide had come right in, we would put our belongings in our duffle bags and swim back. We didn't have much to carry, just a few clothes and a camera each, and we had flippers which would make strong swimmers of us both.
The time came to undertake our swim and off we set, duffle bags held above the still water as we used our flippers to propel us towards the rocky shore. I was about half way when I suddenly doubted that I could make it and was filled with dread and the fear of death. I struggled on, desperately trying to keep myself and my duffle bag above the water, and terrified that I wasn't going to make it. As I got close to the shore I could hear my friend, who had completely disappeared from my thoughts, calling for help behind me. At last, feeling incredible relief, I was able to stand. I threw my bag up onto the rocks and plunged back in to assist my friend, who had come to a stop in the water and was just holding his bag above his head calling for help. Without my bag to support, I was like a cork in the water; like a merman, I swam quickly to my friend and took the bag from him. Immediately we exchanged roles: he became a merman, while I struggled back with his bag to the shore . But we made it: we - and our bags - were saved!
The experience made a huge impression on me: the terrifying fear of death (which one doesn't experience often, thank goodness), and the realisation afterwards that it had been totally misplaced: all I had to do was let go of my bag. But at the time that possibility simply did not enter my head. I thought that I was struggling for my life, when in fact I was merely struggling for my bag, with a few clothes and a cheap camera in it. And my friend had done exactly the same. Before I took it from him he was prepared to go down with it. Granted, his camera was more valuable than mine - but hardly worth sacrificing his life for. Not that he would have had much use for it anyway if he'd drowned.
If I hadn't experienced it myself, I wouldn't have thought it possible: that I could be so stupid as to believe (or rather, blindly assume) that my life depended on me hanging on to a bag with a few, relatively unimportant belongings in it. It didn't cross my mind that letting go of it was all that I had to do to save my life. Neither I nor my friend had realised that holding our bags above the water would make such a big difference to our buoyancy.
The moral of the story (the reason I'm telling it) is this: In life, we are all attached to things. Some are more valuable or important than others. Some things, in certain circumstances, can weigh us down and even threaten our lives (like my friend and I holding onto our bags). It is essential that we recognise what these things are and accept that it may be necessary to let them go.
In the modern world, with its growth-dependent economy and grossly materialistic lifestyles, there are many things which seem valuable, even indispensable, to us. We may have good reason for being reluctant to let go of them, but it won't kill us; hanging on to them will.
What are these things? They are the supernumerary and over-weight "straws" we are placing on the camel's back (The straws that broke the camel's back): gas-guzzling cars and frequent air travel, for example; the failure to give top priority to resource conservation, recycling and renewables (particularly energy) and much, much more besides.
It is difficult for an individual (even among the planet's Greatest Apes) to comprehend that what he or she does (or doesn't do) makes any difference whatsoever: it is always such a tiny, imperceptible drop in the ocean. It requires human insight (something not available to apes) to perceive the imperceptible and recognise that the drops mount up - and to behave responsibly and morally (something else that apes are not capable of) as a consequence.