James Lovelock, the pioneering scientist and environmental guru who came up with the Gaia theory of the Earth, believes it could be time for humanity to “save ourselves” – rather than the planet.

Writing in a forthcoming collection of essays by leading thinkers, called The Earth and I, Professor Lovelock warns that life on Earth is quite close to coming to an end, at least on a cosmic timescale.

As an “elderly biosphere”, the Earth is susceptible to diseases – such as climate change caused by humans.

But Professor Lovelock, whose Gaia theory transformed the way we view the world but is an unlikely environmental hero given his support for nuclear power, the chemical industry and MI5, says talk of trying to “save the planet” is “surely hubris”.

The book features a number of scientists such as quantum physicist Professor Lisa Randall, Astronomer Royal Martin Rees, Professor Edward Wilson, a biologist known as the “father of biodiversity”, and Nobel Prize-winning neuroscientist Eric Kandel.

It has been written not in an attempt to increase the sum of human knowledge, but to help ordinary people understand “who we are, how we live and where we might be going”, according to the publisher Taschen.

Professor Lovelock once feared humanity would end up struggling to survive in the Arctic Circle as global warming made much of the Earth uninhabitable by 2100, although he later said he felt he had been too “alarmist”.

Writing in the introduction to The Earth and I, he says it is “fairly sure that the metabolic carbon form of life cannot go on much longer in cosmic terms”.

“Our star, the Sun, has been a wonderfully reliable source of energy since life began but as it grows older, it increases its output of heat at an exponentially growing rate until eventually it dies in about five billion years by cremating itself in a burst of fire,” he says.

Animals in decline Show all 8 1 /8 Animals in decline Animals in decline Harbour seal (Phoca vitulina) Where: Orkney Islands. What: Between 2001-2006, numbers in Orkney declined by 40 per cent. Why: epidemics of the phocine distemper virus are thought to have caused major declines, but the killing of seals in the Moray Firth to protect salmon farms may have an impact. Alamy Animals in decline African lion (Panthera leo) Where: Ghana. What: In Ghana’s Mole National Park, lion numbers have declined by more than 90 per cent in 40 years. Why: local conflicts are thought to have contributed to the slaughter of lions and are a worrying example of the status of the animal in Western and Central Africa. Animals in decline Leatherback turtle (Dermochelys coriacea) Where: Indonesia, Malaysia, Mexico, Costa Rica. What: Numbers are down in both the Atlantic and Pacific. It declined by 95 per cent between 1989-2002 in Costa Rica. Why: mainly due to them being caught as bycatch, but they’ve also been affected by local developments. Alamy Animals in decline Wandering albatross (Diomedea exulans) Where: South Atlantic. What: A rapid decline. One population, from Bird Island, South Georgia, declined by 50 per cent between 1972-2010, according to the British Antarctic Survey. Why: being caught in various commercial longline fisheries. Alamy Animals in decline Saiga Antelope (Saiga tatarica) Where: Kazakhstan, Mongolia, Russia, Turkmenistan, Uzbekistan. What: fall in populations has been dramatic. In the early 1990s numbers were over a million, but are now estimated to be around 50,000. Why: the break up of the former USSR led to uncontrolled hunting. Increased rural poverty means the species is hunted for its meat Animals in decline Swordfish (Xiphias gladius) Where: found worldwide in tropical, subtropical and temperate seas. Why: at risk from overfishing and as a target in recreational fishing. A significant number of swordfish are also caught by illegal driftnet fisheries in the Mediterranean Animals in decline Argali Sheep (Ovis mammon) Where: Central and Southern Asian mountains,usually at 3,000-5,000 metres altitude. Why: domesticated herds of sheep competing for grazing grounds. Over-hunting and poaching. Animals in decline Humphead Wrasse (Cheilinus undulatus) Where: the Indo-Pacific, from the Red Sea to South Africa and to the Tuamoto Islands (Polynesia), north to the Ryukyu Islands (south-west Japan), and south to New Caledonia. Why: Illegal, Unregulated and Unreported (IUU) fishing and trading of the species

But this increase in solar heat sets a limit on life as we know of about 100 million years, according to his calculations.

“This is a near infinite time in human terms but quite short for the Sun or for life itself,” writes Professor Lovelock, who is now in his mid-90s.

“Even without the impact of human activity, it is an elderly biosphere, and elderly biospheres, like elderly animals, grow more vulnerable to perturbations as they age.

“A disease, like pneumonia, from which one can recover when young, is often fatal for the aged.”

But his suggested strategy for the future is perhaps unexpected – concentrate on humanity, or more specifically our “information”, rather than the Earth.

“Many think our most important task is to try to save the planet, but surely this is hubris,” he writes.

“We are a powerful species, but we are, and always will be, part of a much more powerful planetary system.

“Rather than try to save Gaia, perhaps the most important thing we have to do is to save ourselves and, above all, our ability to think, to understand, to value wisdom, and to process information.”

Professor Lovelock then touches on complex ideas that have been emerging in physics since the work of 19th century Scottish scientist James Clerk Maxwell, who was compared to Isaac Newton by Albert Einstein.

“As far as we know, we remain the only species in the entire history of creation that can examine our history and imagine a different future,” he writes.

“With this unique knowledge of how we came to be, comes a responsibility both to the home we have now, and to some unimaginable future.

“Modern physicists even speculate that information may be the fundamental basis of the cosmos.

“If they are right, then our survival is crucial, even though we, who are here now, may never quite understand why.