Humans, the supremely social mammals, are ethical and intellectual sponges. We unconsciously absorb, for good or ill, the influences that surround us.
As Dutch elm disease spread across Britain in the 1970s, the country fell into mourning. When the sentinel trees that framed our horizons were felled, their loss was a constant topic of sad and angry conversation.
If you or I had lived 500 years ago, our worldview, and the decisions we made as a result, would have been utterly different. Our minds are shaped by our social environment, in particular the belief systems projected by those in power: monarchs, aristocrats and theologians then; corporations, billionaires and the media today.
There are, I believe, three steps to overcoming fear: name it, normalise it, socialise it.
I became an environmentalist because I love the living world, but I spend much of my life thinking about electricity, industrial processes and civil engineering.
Those who deny their own feelings tend to deny other people's.
As a child and young adult, I delighted in being able to identify almost any wild plant or animal.
There is plenty of housing - for the rich. But a series of outrageous policies ensure that it remains inaccessible to the poor.
Surplus money allows some people to exercise inordinate power over others: in the workplace; in politics; and above all in the capture, use and destruction of the planet's natural wealth.
While some livestock farms are much better than others, there are none in this country that look like natural ecosystems. Nature has no fences.
If you construct political narratives around the psychodramas of politicians, even when they don't invite it, you open the way for those who can play this game more effectively.
If commercial fishing were excluded from large areas of the sea, the total catch would be likely, paradoxically, to rise, due to what biologists call the spillover effect.
For many years, wildlife film-making has presented a pristine living world. It has created an impression of security and abundance, even in places afflicted by cascading ecological collapse.
Representative democracy is a remarkably blunt instrument. Hundreds of issues are bundled together at every election, yet the vote tends to swing on just one or two of them.
When I kayak in Cardigan Bay, in Wales, what I hope to find above all else is dolphins. Sometimes I do, and these days are the waymarks of my life.
Immense wealth translates automatically into immense environmental impacts, regardless of the intentions of those who possess it.
We have a wider political and economic system in which ancient, landed power still carries immense weight. There is nothing some landowners would like more than to set the police on those who dare to venture into their vast estates.
David Cameron's government criminalised squatting in empty homes. This too was previously a civil matter. Thousands of homeless people found themselves on the wrong side of the law. Some have been imprisoned for using property abandoned by its owners.
History shows that attacks on general freedoms often begin with an attack on the freedom of a minority. It teaches us that we should never allow a government to divide and rule. An attack on one is an attack on all.
Rather than allowing Roma, Travellers and homeless people to be picked off, all those of us who fear the criminalisation of trespass should join forces with them, protecting their rights while we defend our own.
