The government has set damaging and illogical targets for species recovery in England that could mean there is eight years of decline before any improvement, despite already being at “rock bottom”, scientists have warned the prime minister. Twenty-three leading scientists from institutions including Oxford and Cambridge universities, the Natural History Museum, the Zoological Society of London and the RSPB have written to Boris Johnson expressing their alarm over the nature targets. Although their targets for species recovery have been described as “ambitious” by the Conservative party, scientists said the unusual methodology meant the baseline for improvement could be lower than the current situation. This is because the baseline has been set for 2030, eight years from now. The government’s target is for a 10% increase by 2042 from that date, meaning that even if biodiversity continues to spiral downwards until 2030, the government could still hit these theoretical numbers and call it a success. This is contrary to the G7 ambition to “bend the curve of biodiversity loss by 2030”. The letter says the target “seems to miss the mark”, adding: “No target derived from a baseline that is itself in the future is logically coherent. It removes the urgency for action between now and 2030.” Prof Nathalie Seddon, the director of the nature-based solutions initiative at the University of Oxford, said: “Almost half of species are in decline and over one in 10 species have been pushed towards extinction. We can’t let this situation continue for another eight years. “Given current rates of decline in species abundance, a baseline in the future means our target is to reach biodiversity levels below those of today. In other words, in future, we could claim to have met our target but actually have lower biodiversity than we do now. “By keeping this target, the government is essentially accepting another eight years of species decline in the UK, and that is hard to fathom as we are already at rock bottom, and this continued loss in biodiversity is undermining the health of the habitats on which we depend. “A lot of new development is being planned and a lot of damage can be done in eight years in a small country like ours, we will see a continued decline without ambitious targets and strong policy enforced now.” The scientists have called for a 2022 baseline and a “stretching target which reflects the scale of the nature recovery task ahead”. An example target they have suggested includes an increase in species abundance of 20% or 30% from 2022 to 2042, which could put the UK on a trajectory for species abundance to be close to 1970 levels by 2050. “Such ambition is warranted and essential,” the letter reads. “It is warranted because we have abundant evidence of interventions that work to secure the future of species at risk of UK extinction (eg for bitterns, cirl buntings, marsh fritillaries, greater horseshoe bats). “It is essential because we need a step change in scale of response to ensure that these species don’t simply survive, but thrive, and that declining but still widespread species such as skylarks and curlews are restored and continue to enrich lives and landscapes across the UK.” A Department for Environment, Food and Rural Affairs spokesperson said: “The targets we are consulting on under the Environment Act are ambitious, world-leading and based on the latest science – and we welcome any further evidence submitted to this consultation. “We are going beyond what is required under the convention on biological diversity by proposing legally binding targets to tackle biodiversity loss.”