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.

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.

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.

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.

Immense wealth translates automatically into immense environmental impacts, regardless of the intentions of those who possess it.

The notions that nature exists to serve us; that its value consists of the instrumental benefits we can extract; that this value can be measured in cash terms; and that what can't be measured does not matter, have proved lethal to the rest of life on Earth.

Public figures talk and act as if environmental change will be linear and gradual. But the Earth's systems are highly complex, and complex systems do not respond to pressure in linear ways.

Food production is ripping the living world apart. Fishing and farming are, by a long way, the greatest cause of extinction and loss of the diversity and abundance of wildlife. Farming is a major cause of climate breakdown, the biggest cause of river pollution and a hefty source of air pollution.

Pedestrians and cyclists are squeezed by planners into narrow and often dangerous spaces - the afterthoughts of urban design.

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.

A large body of literature suggests that wellbeing is intimately linked to attachment - not only to other people, but also to the natural world.

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.

I might find myself standing, transfixed, by the roadside, watching a sparrowhawk hunting among the bushes, astonished that other people could ignore it. But they might just as well be wondering how I could have failed to notice the new V6 Pentastar Sahara that just drove past.

As some of us can testify, the viciousness of the lobby groups funded by the fossil fuel industry, and the publications that amplify their message, knows no limits. As we have already seen, they treat even children as fair game.

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.

As SUVs are higher and heavier, they are more likely to kill the people they hit. Driving an SUV in an urban area is an antisocial act.

After 12,000 years of feeding humankind, all farming except fruit and veg production is likely to be replaced by ferming: brewing microbes through precision fermentation.

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.

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.

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.

Emotionally damaged men all too often rip apart their own lives, and those of their partners and children. I see both physical fitness and emotional strength as virtues, but they are acquired by entirely different means.

Never underestimate the power of intrinsic values. They inspire every struggle for a better world.

Rainforests are not confined to the tropics: a good definition is forest wet enough to support epiphytes - plants that grow on other plants. Particularly in the west of Britain, where tiny fragments persist, you can find trees covered in rich growths of a fern called polypody, mosses and lichens, and flowering plants climbing the lower trunks.