The world must rewild and restore an area the size of China to meet commitments on nature and the climate, says the UN, and the revival of ecosystems must be met with all the ambition of the space race. Existing conservation efforts are insufficient to prevent widespread biodiversity loss and ecosystem collapse, the global body has warned at the launch of the decade on ecosystem restoration, an urgent call for the large-scale revival of nature in farmlands, forests and other ecosystems. Governments must deliver on a commitment to restore at least 1bn hectares (2.47bn acres) of land by 2030 and make a similar pledge for the oceans, according to the report by the UN Environment Programme (Unep) and the Food and Agriculture Organisation (FAO) to launch the decade. Humans are using about 1.6 times the resources that nature can sustainably renew every year and the UN said short-term economic gains are being prioritised over the health of the planet. The rallying cry calls on all parts of society to take action, including governments, businesses and citizens, to restore and rewild urban areas, grasslands, savannahs and marine areas. “Restoration needs to be seen as an infrastructure investment in a country’s wellbeing. We need imagination,” said Tim Christophersen, coordinator of the decade on ecosystem restoration. “For many people, I think restoring a billion hectares is a bit abstract. We have decades of experience of how this could work but never on the scale we’re talking about. We have space programmes and nuclear weapons – it is possible.” Half the world’s GDP is dependent on nature and the degradation of ecosystems is affecting about 40% of the world’s population already, threatening human health, livelihoods and food security, according to the foreword written by the Unep executive director, Inger Andersen, and the FAO director-general, Qu Dongyu. The report notes that while restoration science is in its infancy, agroforestry and other sustainable farming practices are already well understood and can be scaled up. The UN has said it will work with governments to highlight flagship restoration projects to inspire the ambition required. “This kind of large-scale restoration has not been done very often. There are a few examples in China and with the Atlantic rainforest in Brazil, but at the scale that we now need it, very few examples exist,” said Christophersen. “They are investments that sometimes have a similar complexity to large infrastructure projects.” Countries have already committed to restoring 1bn hectares of degraded land – roughly the area of China – according to a study by the Dutch environmental assessment agency. Many of these pledges have been made by countries in sub-Saharan Africa, Latin America, China and south Asia, with relatively few made by western nations, Russia and those in the Middle East. Christophersen said more were expected in the next few years to complement initiatives such as the Great Green Wall in Africa, which aims to restore 100m hectares of degraded land by 2030 to combat desertification. The report’s authors said lessons must be learned from previous mistakes – such as planting monoculture trees and exotic species – and countries need help finding solutions that fit their geography and climate. “Even if we feel the science is not mature enough, it should not really stop us from taking action. What you have as a model approach in one ecosystem might not apply in others. So there are many different sorts of ways about it,” said Corli Pretorius, deputy director of the Unep World Conservation Monitoring Centre. “It depends so much on the local context. This is not only about the environment: it is for people as well, through safeguarding livelihoods, giving people access to nature in urban areas or improving health.” In February, a review commissioned by the British government on the effect of human economic activity on life-sustaining ecosystems found development had come at a “devastating cost” to the natural world. Led by Prof Sir Partha Dasgupta, a Cambridge University economist, it concluded that radical change to production, consumption, finance and education was needed. Last week, the UN’s State of Finance for Nature report found the world needs to quadruple its annual investment in nature if the climate, biodiversity and land degradation crises are to be tackled by the middle of the century. It highlighted a finance gap of $4.1tn (£2.9tn) that needed to be closed to avoided the breakdown of natural ecosystem “services” such as clean water, food and flood protection.