Save the rainforest: How the killing of Cecil has a more deeper meaning than the death of just "one lion".

Last week, Walter Palmer, the smiling rich American dentist, killed a protected lion in Zimbabwe sparking worldwide outrage. After luring Cecil out of his protected habitat, Walter shot the lion with his bow and arrow, then to his gratification, left him in agony for a further 40 hours before returning to finish him off with a gun shot to the head. Cecil was then beheaded and skinned, with his head taken back to Walter's house as a trophy.

Cecil was not just "any lion", he was the head of a pride and one of Africa's most famous, that brought in millions of pounds to Zimbabwe's Hwange National Park each year. Cecil, aged 13, wore a radio collar installed by researchers from Oxford University who were studying his pride’s movements. This vital research is now severely disrupted.

However, the killing of Cecil and the global outrage that followed has a much deeper significance. It is not simply the killing of one lion but instead symbolises the diminishment of the whole animal kingdom and how mankind is degrading and destroying his own planet.

Cecil represented a species that is on the brink of extinction. His death speaks of a trade in which thousands of wealthy white Westerners travel to Africa to exploit and destroy its wildlife. Thousands of lions are now being bred in farms to be later shot by trophy hunters in a fenced park. The bones of the dead lions are then sold to China, where they are used in traditional Chinese medicine. This demand has helped drive the number of lions in the wild from 275,000 in 1980 to less than 20,000 today.

It is not only lions that are suffering. Since 1970 the earth has lost 52% of all wildlife.

Elephants are also now under threat. We are now losing 100 elephants a day in Africa due to the ivory trade, equivalent to one elephant being poached each 15 minutes. The numbers are truly shocking. In the last three years alone we have lost nearly 100,000 elephants. The Tanzanian elephant population has declined by more than 60% in the last five years alone, with the forest elephant numbers in Africa dropping by 65%. Fiona Maisels, a biologist with the Wildlife Conservation Society, notes "by the time you eat breakfast, another elephant has been slaughtered to produce trinkets for the ivory market." If nothing is done to stop this, the elephant will disappear from the wild within a decade.

The wild Rhino is also on the brink of extinction. There are now only four (yes, four) Northern White Rhino left on earth and over 1,215 were poached last year. The horn – which is made of nothing more exotic than keratin (the same substance as your fingernails) – is then shipped to Asia, where it is believed it can cure cancer and increase sexual gratification. The rhino's horn is often sawed off the animal while it is still alive.

The palm oil industry is continuing to desecrate Indonesia's rainforests and encroach on the only ecosystem in the world (the Leuser ecosystem in Sumatra) where organutan, tiger, rhino and elephant cohabit. Palm oil is a vegetable oil which is contained in one in ten of our supermarket products; it is responsible for killing thousands of orangutans each year, many of which are burnt alive. As a result of this growing demand, Greenpeace have stated that Indonesia is set to lose 98% of all its rainforests by 2022.

Tigers are also now critically endangered, with only 3,500 left in the wild. Their numbers have dropped from 100,000 at the beginning of the century. Tigers are poached for their body parts which are used in traditional Chinese medicine. Like lions, tiger are also farmed in China for their hides and bones which are used in wine. There are now more tigers in Chinese tiger farms than exist in the wild in the rest of the world.

The sun bear is also a casualty of this ruthless farming industry. With possibly less than a 1,000 remaining in the wild, thousands of sun bears in China are farmed, muzzled and kept in tiny cages where they are milked for the bile in their gall bladders, all for useless “medicine” in the Asian market.

While all this is graphic and upsetting, it represents the stark reality for many endangered species across the globe. According to the WWF, the illegal wildlife trade is now worth more than £12 billion pounds a year. Tragically, wildlife is now worth more dead than alive.

However, it does not have to be this way. Cecil does not have to die in vain. As a conservationist, I will continue to dedicate my life to saving what we have left. But much more needs to be done: governments need to take firmer action; education in Asia needs to be increased; and the illegal wildlife trade stopped. Humanity needs to overcome greed, corruption and ignorance to protect the vital ecosystems that we have left.

The earth, which has existed for 4.5 billion years, is in danger of losing all of its nature – the precious fruit of billions of years of evolution – within a matter of decades. When we reach that point, I really hope we do not look back and simply say "we should have done more".

In memory of Cecil, and the countless unnamed