More than a dozen factors, ranging from declines in flowering plants and the use of memory-damaging insecticides to the world-wide spread of pests and air pollution, may be behind the emerging decline of bee colonies across many parts of the globe.

Scientists are warning that without profound changes to the way human-beings manage the planet, declines in pollinators needed to feed a growing global population are likely to continue.

  • New kinds of virulent fungal pathogens-which can be deadly to bees and other key pollinating insects-are now being detected world-wide, migrating from one region to another as a result of shipments linked to globalization and rapidly growing international trade
  • Meanwhile an estimated 20,000 flowering plant species, upon which many bee species depend for food, could be lost over the coming decades unless conservation efforts are stepped up
  • Increasing use of chemicals in agriculture, including 'systemic insecticides' and those used to coat seeds, is being found to be damaging or toxic to bees. Some can, in combination, be even more potent to pollinators, a phenomenon known as the 'cocktail effect'
  • Climate change, left unaddressed, may aggravate the situation, in various ways including by changing the flowering times of plants and shifting rainfall patterns. This may in turn affect the quality and quantity of nectar supplies.

These are among the findings of a new report published by the UN Environment Programme (UNEP), which has brought together and analyzed the latest science on collapsing bee colonies.

The study, entitled Global Bee Colony Disorders and other Threats to Insect Pollinators, underlines that multiple factors are at work linked with the way humans are rapidly changing the conditions and the ground rules that support life on Earth. It shows humans' large dependency on ecosystem services even for such vital sectors as food production.

It indicates that bees are early warning indicators of wider impacts on animal and plant life and that measures to boost pollinators could not only improve food security but the fate of many other economically and environmentally-important plants and animals.

The authors of the report call for farmers and landowners to be offered incentives to restore pollinator-friendly habitats, including key flowering plants including next to crop-producing fields.

More care needs to be taken in the choice, timing and application of insecticides and other chemicals. While managed hives can be moved out of harm's way, "wild populations (of pollinators) are completely vulnerable", says the report.

Achim Steiner, UN Under-Secretary-General and UNEP Executive Director, said: "The way humanity manages or mismanages its nature-based assets, including pollinators, will in part define our collective future in the 21st century. The fact is that of the 100 crop species that provide 90 per cent of the world's food, over 70 are pollinated by bees".

"Human beings have fabricated the illusion that in the 21st century they have the technological prowess to be independent of nature. Bees underline the reality that we are more, not less dependent on nature's services in a world of close to seven billion people".