NAIROBI: Environmental damage caused by man-made activities is having a devastating toll on human health, the United Nations said on Wednesday, warning of millions of premature deaths due to air and water pollution by 2050 if action was not taken.

Seen as the most comprehensive and rigorous assessment on the state of the environment, the UN's Global Environment Outlook said human health - was in "dire straits" due to unsustainable development and poor environmental protection.

Air pollution from vehicles and industry as well as burning fuels such as wood, coal and kerosene for cooking, heating and lighting was resulting in around 7 million deaths annually, said the report - costing around $5 trillion in welfare losses.

Water quality has worsened due to increased organic and chemical pollutants such as plastic, pathogens, heavy metals and pesticides. Almost 1.5 million people die annually due to diseases related to drinking pathogen-polluted water, it said.

"Our key message is that a healthy planet enables healthy human life and that the planet is becoming increasingly unhealthy and this is impacting our health," said Joyeeta Gupta, one of the leading scientists who worked on the report.

"The causes of an unhealthy planet need to be addressed."

The 740-page report - compiled over six years by 250 scientists from 70 nations - said human activities could endanger the "ecological foundations of society" and called for unprecedented action.

It was released at the UN Environment Assembly, a five-day summit where environment ministers plan to commit to creating a more sustainable planet, from reducing food waste and plastic pollution to developing technologies to combat climate change.

TRANSFORMING FOOD, ENERGY, WASTE

UN officials said the health and prosperity of humanity were directly tied to the state of the environment and there was a need to transform to more sustainable models of development.

"The Global Environment Outlook has a very clear message: we cannot transform the world by tweaking around the edges," said Joyce Msuya, acting executive director of UN Environment.

"We need to look at transforming how we pro-duce and consume in the areas of food, energy and waste to ensure a healthy future for all."

The agriculture sector, for example, is not only a significant contributor of greenhouse gas emissions, she said - one-third of food produced globally was being wasted, yet demand for food was rising due to population growth.

While production of renewable sources of energy was at an all-time high, two-thirds of the world's electricity still came from fossil fuels, said Msuya.

"It's time to value waste and discard our current model of economic growth and the mountains of waste that have come to characterise our urban spaces and waterways," she said.

The report provided a slew of suggestions to help policymakers tackle challenges from reducing carbon emissions and curbing plastic pollution to tackling food waste.

Adopting less meat-intensive diets and reducing food waste, for example, would reduce the need to increase food production by 50 per cent to feed an estimated 10 billion people on the planet in 2050, said the report.

Experts said it was time to end the "grow now, clean up after" model of economic development - and there were growing signs that people are asking for such a transformation. It was now time for their governments to listen, they added.

"We know what the problematic human behaviours are that are affecting our environment - it's the way we eat, it's the way we get around, it's the energy we use to power our homes and it's how we build our homes and all the infrastructure that goes with that," said Paul Ekins, who also worked on the report.

"There are signs that all those behaviours are under question - from movements towards eating less meat to movements towards switching to electric vehicles. We now need to universalise these habits and behaviours."