A million species of plant and animal are at risk of extinction

ACCORDING TO THE Book of Genesis, Noah saved the animal kingdom by bringing “every living thing of all flesh, two of every sort..male and female” into the Ark. But what if the last two of a sort cannot breed? This is the problem facing the northern white rhinoceros, the world’s most endangered mammal. Najin and Fatu, the last two such rhinos on Earth, are both females, living in the Ol Pejeta Conservancy in Kenya. To salvage the subspecies, a group of scientists harvested eggs from the two and inseminated them with sperm collected from Suni and Saut, two bulls in a Czech zoo, before their deaths. Any viable embryos will be implanted in the uterus of a surrogate southern white rhino (another, less endangered, type). If the procedure is successful, a mammal will have been brought back from functional extinction for the first time.

The northern white rhino, which ranged across the savannahs of central Africa before being wiped out by armed conflict and poachers, is just one of many species that are critically endangered because of human activity. According to a UN report published in May, nature is being destroyed at a rate “unprecedented in human history”. A million species of animals and plants are at risk of extinction, equivalent to more than a tenth of the number of species on earth. A separate paper by a group of researchers led by James Allan of the University of Queensland identifies “hotspots” where the greatest number of land animals are threatened by human activities such as agriculture, urbanisation and transport (see map). Some of the worst affected countries are in South-East Asia, including Indonesia, Malaysia, Myanmar and Thailand. Many species are also in danger in southern Brazil and north-east India. A study published this week in the journal Science estimates that bird populations across North America have fallen by 29% since 1970, equivalent to around 3bn birds.

The northern white rhino and some others may be saved at the eleventh hour. Scientists are even discussing the resurrection by gene editing of long-extinct animals, notably the woolly mammoth. To prevent species from reaching the brink of extinction in the first place, conservation and monitoring are a help. So is discouraging or prohibiting activities that threaten animals at risk. But that is easier said than done. Habitats are being lost to urbanisation: cities have doubled in size in the past 30 years. Without programmes to give local people an interest in the survival of endangered species, enforcement to end the illegal trafficking of wildlife products may fail. More species will surely be lost to the flood.