Most people haven’t understood that we have no idea about the vast majority of things on Earth. We haven’t collected or identified them. We don’t know anything about their life histories, their ecology, where they live or what they do. We are still ignorant about the vast majority of the Earth’s biodiversity; so, in fact, we don’t know what it is that we’re losing. It’s also surprisingly difficult to tell when you’ve lost the last individual of a species. You’ve got to look very hard to know there’s no more of it left. Documenting extinctions, therefore, is quite difficult.

The best we can do is infer that something has become extinct statistically and make judgements about the overall rate. It is because it’s so complicated to observe directly that it’s very hard to motivate people to do anything about it. It’s also difficult for us to communicate the extent of these processes or the rapidity with which they are unfolding in geological time. We are relatively short-lived as individuals – 80, 100 years if we’re lucky – but ecological and evolutionary timescales are much longer than that. As a consequence, we tend to reset our thinking about what is natural and what is to be expected with each new generation of humans, and we lose sight of how quickly things are changing around us. These changes are coming like a locomotive. We’re not prepared, and we’re being very slow to adjust our thinking and our way of interacting with the environment to ensure that the place in which we live continues to be liveable.

Society needs to change the way it considers personal aspirations and to have a better view of the collective impact of our activities on the environment. I don’t know that I can see another solution, because the idea that we can tell people things are bad and they’ll change their minds is not going to work. It may be an intractable problem. People talk about benign transitions being changes in societies – societies as a whole that move towards a more sustainable future – and transitions that are not benign, those which precipitate crises that lead to enforced changes in behaviour.

We may see things precipitated by climate change, for example, that transcend our expectations, that lead to more rapid changes than we are currently expecting. If those things happen, if the tail distributions of our expectations arise and sea levels and temperatures change more than we think, there could be wholesale changes to economic food systems that trigger changes in the way society behaves. My deep fear about those scenarios is that the people who are most likely to suffer the most serious consequences of those transitions are the people most vulnerable to them: people who are poorest, people in the least able circumstances, people who are in societies who are least able to respond will bear the consequences of the decisions that we, globally, are taking as we speak.

Designating protected areas, marine parks, national parks, terrestrial areas and freshwater zones is about creating legislation to protect endangered species so that when a species is threatened, we can impose particular restrictions on what people can do in its habitat. There’s expenditure on ecosystem services and on enhancing the interactions between people and their environments in various places around the world that will both conserve biodiversity and find better solutions for people’s livelihoods.

There are certainly success stories. There are species which, without human intervention, would have become extinct. There are species that will probably persist long-term because of the things that people have done. They give us some hope that our knowledge can be used to good effect to at least delay, if not stave off, the extinction of some of the species that we’re affecting. They’re all great actions, but there are simply not enough of them around the world to make a big enough difference.

With regard to the fires and the Australian landscape, I think particularly of animals like the Leadbeater’s possum. The Leadbeater’s possum was thought to be extinct, and was rediscovered in the central highlands of Victoria a few decades back. It lives in cavities in ancient trees, in a landscape that is characterised by fire. In the places that are frequently burned, there are large, old eucalyptus trees. These trees can be up to 100 metres tall and with very large girths. It takes them a long time to grow. When these trees are about 100 or 125 years old, they start to develop cavities: branches start to fall, and the Leadbeater’s possum forms dens in their cavities. It takes a long time for the habitat that this species needs to emerge after a fire.

It needs places that burn, but only burn every 200 or 400 years. As a consequence, the habitat it requires is extensive and rather grand. It’s a spectacular-looking place. With the fires occurring as often as they currently are, the habitat for that species will be lost. Now, that’s a consequence of there being more people around – and people do tend to light fires – and it’s a consequence of lightning strikes. Fires are essentially a product of how hot it is, how much fuel there is and whether there’s a source of ignition. With climate change, increasing temperatures, increasing human population size, those things are just getting worse, and the habitat for this species is shrinking.