Countries from around the world set their sights Monday on a pivotal deal to curb plastic waste, a source of long-term pollution and worsening contamination of the ocean's food chain.
Thousands of delegates, business leaders and campaigners are in Nairobi for the five-day UN Environment Assembly, the top annual forum on the planet's environmental crisis.
The UN wants individual countries to sign up to "significantly" reduce plastic production, including a phasing out of single-use plastics by 2030 -- a goal inspired by the 2015 Paris Agreement on voluntary reductions of carbon emissions.
"In the field of (plastic) pollution we don't have such agreements," Siim Kiisler, UN Environment Assembly president and Estonia's environment minister, told journalists as the gathering got underway.
"This is the first time (we have) to convince member states to make international commitments."
A landmark report due out this week is expected to ram home the warning of the threat to ecosystems from rampant plastic and chemical waste.
The world currently produces more than 300 million tonnes of plastics annually, and there are at least five trillion plastic pieces floating in our oceans, scientists have estimated.
Microplastics have been found in the deepest sea trenches and high up Earth's tallest peaks, and plastic consumption is growing year-on-year.
"Plastic is a very good material, it's durable, flexible and light," Kiisler said. "This means we should make the best out of it for as long as possible instead of disposing of it."
The conference started on a sombre note after an Ethiopian Airlines jet crashed on Sunday, killing all 157 on board, many of whom were heading to the event.
The Nairobi meeting comes against the backdrop of series of UN reports outlining in stark terms the damage mankind is doing to the planet, much of it due to reckless consumption.
"These things are all linked: climate, the environment, waste," one delegate told AFP.
One briefing on the eve of the summit said the cost of ecosystems loss through agriculture, deforestation and pollution was a much as $20 trillion (17.7 trillion euros) since 1995.
Acting UN environment chief Joyce Msuya said the world needed to "transform the way our economies work... break the link between growth and increased resource use, and end our throwaway culture."
The One Planet Summit on Thursday will bring together heads of state including French president Emmanuel Macron and Kenyan counterpart Uhuru Kenyatta to lend political clout to the process.
Kiisler said it was a "critical time for action to protect and reverse the degradation of our planet.
"We are not going fast enough," he told reporters.
"Today we are talking about declarations and commitments but I believe in the future we need some international legislation in place."
The UN on Monday also warned that the global scale of chemical production was likely to double between now and 2030.
A study it commissioned found that worldwide chemical production capacity stands at 2.3 billion tonnes and is growing despite repeat warnings from environmental groups of the dangers hazardous materials pose to ecosystems.