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 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.

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.

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.

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

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.

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

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.

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.

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.

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.

Farmfree production promises a far more stable and reliable food supply that can be grown anywhere, even in countries without farmland. It could be crucial to ending world hunger.

I have tried to keep my eco-anxiety at bay, to box it into my working life. But every month this becomes more difficult. The rising sense of panic I feel is entirely rational; we should all be feeling it. But we can't live with it through every hour of every day.

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.

If we stop dragging trawls and dredges through it, the life of the seas would recover with astonishing speed. Because most marine animals are highly mobile during at least one stage of their development, the rewilding of the seas needs little help from humans.

We are often told that curtailing the freedom of business is coercive and undemocratic. But by what democratic principle should corporations and billionaires decide the fate of current and future generations? When a government releases them from regulation, it allows them to determine whether other people live or die.

The justification for early boarding is based on a massive but common misconception. Because physical hardship in childhood makes you physically tough, the founders of the system believed that emotional hardship must make you emotionally tough. It does the opposite.

When expressions of emotion are dangerous, and when you are constantly told that this terrible thing is being done for your own good, you quickly learn to hide your true feelings, even from yourself.

I could see the point of Brexit if it meant returning power to the people.

We urgently need more trees, but we appear to believe that the only means of restoring them is planting. We have a national obsession with tree planting, which is in danger of becoming as tokenistic as bamboo toothbrushes and cotton tote bags.

We should continue to mobilise against the destruction of the world's great habitats, and its terrifying implications. But the most persuasive argument we can make is to show we mean it, by restoring our own lost wonders.

It doesn't matter how many solar panels you install if you don't simultaneously shut down coal and gas burners.

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.

There's nothing good about ash dieback, but there is one useful thing that could be done: wherever possible, leave the dead trees to stand. There is more life in a dead tree than in a living tree: around 2,000 animal species in the UK rely on dead or dying wood for their survival.

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 we want to prevent both climate and ecological catastrophes, the key task is to minimise the amount of land we use to feed ourselves, while changing the way the remaining land is farmed. Instead, governments almost everywhere pour public money into planetary destruction.

Brexit, for all its likely harms, represents an opportunity to pay landowners and tenants to do something completely different, rather than spending yet more public money on trashing our life-support systems.

There is plenty of housing - for the rich. But a series of outrageous policies ensure that it remains inaccessible to the poor.

In politics, almost everywhere we see what looks like the externalisation of psychic wounds or deficits.

For some people, it is easier to command a nation, to send thousands to their deaths in unnecessary wars, to separate children from their families and inflict terrible suffering, than to process their own trauma and pain.

I believe that anyone who wants to stand in a national election should receive a course of psychotherapy. Completing the course should be a qualification for office. This wouldn't change the behaviour of psychopaths, but it might prevent some people who exercise power from imposing their own deep wounds on others.

I want to be represented by people who are thoughtful, self-aware and collaborative. What would a system that elevated such people look like?

The high seas - in other words, the oceans beyond the 200-mile national limits - are a lawless realm.

Until fishing is properly regulated and contained, we should withdraw our consent. Save your plastic bags by all means, but if you really want to make a difference, stop eating fish.

For some of Britain's most powerful people, hunting and shooting are primordial rights, and any challenge to them is treated as illegitimate. They assert ownership not only of the land but also of the social relationships surrounding it.

Landowners, farmers and gamekeepers, though they comprise a small minority of the rural population, claim to speak for everyone, and dismiss those who challenge them as interfering urbanites.

While some people have rejected capitalism gladly and swiftly, I've done so slowly and reluctantly. Part of the reason was that I could see no clear alternative: unlike some anti-capitalists, I have never been an enthusiast for state communism.

Economic growth is the aggregate effect of the quest to accumulate capital and extract profit. Capitalism collapses without growth, yet perpetual growth on a finite planet leads inexorably to environmental calamity.

As the scale of economic activity increases until capitalism affects everything, from the atmosphere to the deep ocean floor, the entire planet becomes a sacrifice zone: we all inhabit the periphery of the profit-making machine.

Healthy populations of predatory crabs and fish protect the carbon in salt marshes, as they prevent herbivorous crabs and snails wiping out the plants that hold the marshes together.

What I love about natural climate solutions is that we should be doing all these things anyway. Instead of making painful choices and deploying miserable means to a desirable end, we can defend ourselves from disaster by enhancing our world of wonders.

Technological change is essential, but to a natural historian it often feels cold and distancing.

Yes, the car is still useful - for a few people it's essential. It would make a good servant. But it has become our master, and it spoils everything it touches.

A central task for any campaign is to develop a narrative: a short, simple story explaining where we are, how we got here and where we need to go.

Successful movements also need an organisational model that allows them to keep growing.

In thinking about male identities, I'm struck by the inadequacy of the terms we use. The notion that men should be distant, domineering and self-seeking is often described as toxic masculinity, but this serves only to alienate those who might need most help.