An environmental catastrophe struck Europe thousands of years ago, annihilating one of its most magnificent animals.
For millennia, Europe had been the natural habitat for lions, who roamed from Britain to the Urals. Their memory remains in heraldry, folklore and legend.
But the lions themselves, beautiful and strong, were obliterated by an invasion of something new and dreadfully destructive. Not a single wild lion remains in Europe. What was this terrible agent of extermination?
It was us. Homo sapiens, our species, evolved in East Africa about 200,000 years ago. In those early days, the big cats and other large predators were our mortal foes, and threatened our existence.
They were stronger, faster and tougher than us. But somehow we survived. Then, about 100,000 years ago, a small group of us left Africa and radiated around the world. About 45,000 years ago, we entered what is now called Europe.
We were still desperately poor hunter- gatherers, requiring vast areas to sustain our small numbers. But we now had spears, clubs, axes and fire, and much better strategies and co-ordination. We were now a match for the lions.
We saw them as a threat and a competitor, menacing us, killing the animals we wanted to eat, occupying the habitat we wanted to live in. We regarded them as dangerous vermin. So we annihilated them.
Today Europeans spend fortunes visiting Africa on safari and taking photographs of lions, which they now adore and value. In the past we humans regarded lions as a liability; now we regard them as an asset.
Africa is the least developed continent on Earth but has the world's greatest proliferation of large wild animals.
This is a paradox, since it is poor people, not the rich, who are the greatest danger to wild animals. It has been suggested that since African wild animals were exposed to humans for much longer than elsewhere, they learnt how to avoid them.
While there may be some truth in this, more importantly, Africa is very large and straddles the equator. It therefore has an enormous number of life forms (the closer to the equator, the greater the biodiversity). People simply have not had time to kill this multitude of animals. But we are doing so right now.
The African environment is under threat everywhere. We are driving wild animals out of their habitats or killing them for their meat or body parts. We are hacking down forests for firewood or to make way for inefficient subsistence agriculture.
Bodies of water, such as Lake Chad, have shrunk because of bad damming and irrigation. Overgrazing of livestock, for example in the Sahel, and slash-and-burn subsistence farming is causing calamitous soil erosion.
Sprawling settlements of desperately poor people are poisoning the air and fouling waterways. In almost every African city or town, the impoverished are living in squalor and prompting environmental degradation.
Can the African environment be saved? Yes, in a very simple, certain and guaranteed way: development. The continent's ecosystems can be rescued only if African countries develop modern economies, with modern industry, farming, technologies and systems of government, and if African people become richer. There are four fundamental reasons for this.
First, richer people have fewer children than poor. Second, unlike older technologies, modern ones are cleaner, more efficient and use fewer resources, including land.
Third, people move from the countryside to the cities as countries develop. And fourth, rich people care more about the environment than the poor because they can afford to.
All of these tendencies are thoroughly benevolent. Some are surprising. It is not obvious that rich people have fewer children. But they do, in every country and society.
Only one method for reducing population growth is even more potent than wealth: the education of girls.
A 2011 report from the United Nations Department of Economic and Social Affairs, among other similar studies, shows that the more years of schooling a girl has, the fewer children she is likely to produce. Of course education and development go hand in hand.
Urbanisation should be welcomed. It is mad to encourage people to stay in the countryside. When people are living close to each other in cities, towns and suburbs, it is much cheaper and more efficient to supply them with water, transport, electricity, sanitation, goods and services, and far better for the environment, than if they are living far apart in rural areas.
Much of the countryside now occupied by people should be abandoned and given back to nature and her wild animals.
There is a widespread fallacy that economic growth is dependent upon physical resources, and that you cannot have infinite growth with finite resources.
Modern technology uses resources more and more efficiently; and many such as iron, copper and platinum can be recycled forever. They are finite in mass but infinite in time.
In 1740 the most accurate timepiece in the world was John Harrison's H2 clock, which the English clockmaker invented to improve navigation. It weighed 40kg and cost more than a million rand (about $95,000) in today's money.
Nowadays, a cheap watch weighing 20g (2,000 times less) and costing a few hundred rand is far more accurate and reliable.
Even more spectacular reductions in raw materials and improvements in efficiency have been made in communications, electronics and computing.
Most of Africa uses rudimentary technologies that are wasteful of resources; turning to modern technologies would save the resources and make Africans richer.
Africa has a priceless advantage over Europe in the past: it does not have to invent technologies; they are ready at hand. It just has to install them.
Bjørn Lomborg, director of the Copenhagen Consensus Center, a think-tank, has shown how pollution increased at the beginning of England's industrial revolution with the introduction of primitive and dirty engines. It rose to a maximum and then fell as the machines became cleaner and more efficient. Finally there was less pollution than before the industrial revolution.
The state of the air in London is a good example. For heating households, London began to use the new technology of coal in the 13th century to replace the old technology of wood.
Air pollution increased and in 1306 King Edward I tried unsuccessfully to ban coal burning. Primitive coal-burning steam engines in the 18th and 19th centuries made things worse.
But then the engines became cleaner and more efficient, stoves improved, regulation became more effective and alternative cleaner heating became available. Today London's air is cleaner than it was in the 13th century.
Africa does not have to go through this 800-year process; it can leap immediately to the new clean technologies of electricity and liquefied petroleum gas for heating and cooking, and modern motors and engines for locomotion and power.
In the ideal environmental world, which is completely practicable and indeed is already evolving, most humans would live in cities and suburbs, occupying a tiny fraction of the Earth's surface; a small number of commercial farmers would occupy a much larger but still minor area and grow food for us all; and the rest of the land would be returned to nature.
The wild animals would get their habitat back. Modern farming uses less and less land for the same crop yields.
Although a modern "organic" farm can grow as much per hectare as a commercial farm, it requires more labour and is less efficient at delivering food to the customer - which is Africa's greatest problem in the realm of food supply.
A 2011 UN report estimated that "grain losses in Africa after harvest amount to $4 billion a year, enough to provide the minimum annual food requirement of 48m people". Africa should strive for this ideal and attainable world. It is important to realise why Africa is the least developed continent.
Only two factors have led to the successful development of any country: geography and institutions -systems of government, administration and law.
In the beginning of our civilisation, geography was all-important. Today geography hardly matters, and institutions are now essential.
The most important revolution in human history was agriculture, which led to civilisation. Agriculture allowed food surpluses and freed a class of people from labour.
They became priests, administrators, accountants, engineers and kings, and developed writing, science and technologies. Agriculture in its beginnings depended entirely on geography.
In "Guns, Germs and Steel", Pulitzer prize-winner Jared Diamond explains why the geography of Europe and Asia 10,000 years ago favoured agriculture and Africa's did not.
Farming was slow in coming to this continent. Geography is the unmitigated explanation for the relative backwardness of Africa today.
Today geography has been overcome. Any country, regardless of geography, can develop successfully. Success or failure depends only on governance.
North and South Korea have the same geography and people. But South Korea is prosperous, inventive and successful and North Korea is impoverished, stagnant and hungry.
The institutions explain why: those of the former permit free enterprise, democracy and rule of law, whereas the latter's communist despotism prevents development.
The only way to save the African environment is to develop African economies, and the only way to do this is through honest, efficient, competent, limited government with the rule of law, an impartial judiciary and free enterprise and trade.
Infrastructure is all-important. Perhaps nothing drags Africa down as badly as its poor roads, railways and ports; its appalling electricity; its wretched systems of water supply and sanitation.
Yet it has the means to remedy all of these. Africa has by far the world's greatest unused potential for hydro-electricity and huge resources of coal and gas.
Nuclear power, used on the continent only in South Africa, could be used elsewhere with the coming generation of small modular reactors (SMRs).
Solar and wind power could provide off-grid electricity for households and remote clinics and schools. The technologies for good roads, railways and water reticulation are fully developed and only require implementation.
Infrastructure is the best investment a poor country can make. Money could be raised for it in most countries. Lack of money is not the cause of Africa's bad infrastructure.
Rather, it is dishonest and incompetent management and administration. Corruption fouls many government contracts for new infrastructure. The absence of expertise, interest and accountability leads to maintenance failure and existing infrastructure crumbles into disrepair.
Africans, like people elsewhere, want modern, clean technology that will save their environment. No African woman would choose to spend hours every day cutting branches for firewood if she could turn a switch on an electric stove or press the lighter of a gas cooker. And no African man would choose the dangers and small rewards of poaching if he could have a well-paid job in a factory.
Malaria, which kills about 596,000 Africans, mostly children, every year can readily be overcome with good public health systems, as has been shown all around the world. In the 17th century malaria was still widespread in southern Europe and the marshlands of England.
But it has since been virtually eradicated from Europe, thanks to water treatment, better sanitation, and the proper application of insecticides such as DDT.
South Africa, for example, had 60,000 cases of malaria in 2000. After a programme of spraying the inside walls of dwellings with DDT, they were reduced to under 7,000 in 2012. Again the problem and the solution is good government management.
There is a desperate race against time for the African environment. Africa must develop quickly before poor Africans do to African lions what poor Europeans did to European lions.
It has many things in its favour: a treasure trove of natural resources, a youthful population (unlike Europe and Japan) and the lessons of other countries to learn from.
It must look for guidance to the success of South Korea and the spectacular recent advances of China, while taking note of its problems.
In the last decade or so, many African countries have seen high economic growth of 5% or more. Democracy, confirmed by its highest test of removing a government by an election - for example in Sierra Leone in 2007, in Zambia in 2011, in Ghana in 2012, among others - is spreading to more African countries.
Development and good governance will save the African environment, but this is easier to say than to realise. Still, there are reasons for hope.