In its first ‘Economic Case for Nature’ report, the bank looked at how many economies rely on biodiversity and how they would cope if certain services provided by nature collapsed.
The bank found sub-Saharan Africa and South Asia would be worst hit.
The study identified key "eco-system services" that it said were close to tipping points, including wild pollinators and provision of food from marine fisheries and timber from native forests.
"It's not just about biodiversity, it's about the economy – the moment to act is now," report co-author Gianni Ruta, lead environmental economist at the World Bank, said.
Better conservation and management of natural areas, such as parks, oceans, forests and wildernesses, are seen as essential for protecting the natural systems on which humans depend and meeting targets to reduce planet-warming emissions.
Global annual spending to protect and restore nature on land needs to triple this decade to about $350 billion [£254bn] by 2030 and rise to $536bn [£389bn] by 2050, a United Nations report said in May.
But many political leaders have yet to grasp the economic benefits of conservation, relying instead on exploitation of natural resources to lift their people out of poverty, environmentalists say.
The World Bank projected that 51 countries, with a combined population of 1.6 billion people, would experience an overall fall in gross domestic product (GDP) of 10 to 20 per cent by the end of this decade if vital ecosystem services collapse.
Sub-Saharan Africa and South Asia would face an annual GDP contraction of 9.7 per cent and 6.5 per cent respectively, it warned.
This is because they depend on pollinated crops and, in the case of sub-Saharan Africa, on forest products.
They also have a limited ability to switch to alternatives that will be less affected by climate change, pollution and land degradation, the report said.
Among the hardest-hit will be Democratic Republic of Congo, Angola, Madagascar, Ethiopia, Bangladesh and Pakistan, the bank added.
Mr Ruta said governments should channel agricultural subsidies away from things that harm biodiversity such as fertilisers, diesel for irrigation equipment and incentives to farm unsuitable land.
Instead he urged them to promote sustainable farming and reward groups that conserve natural areas on their land.
Mr Ruta also called for a global funding mechanism to help developing nations achieve green shifts.
A coalition of about 60 countries is pushing to protect at least 30 per cent of land and oceans by 2030 – known as the 30x30 proposal – ahead of a UN biodiversity summit in China, set for October, and the COP26 summit to be held in Glasgow in November.
The World Bank report urged more nations to back the 30x30 proposal, adding the financial benefits from maintaining eco-system services would almost completely offset the costs of protecting additional land to meet the target.
Governments should also include more green policies in their pandemic stimulus packages, it added.
"Preserving nature and maintaining its services are critical for economic growth," said World Bank Group president David Malpass.