Wealthy communities will be able to buy their way out of the unfolding climate crisis while the poorest will suffer most, a UN report has found.

Even under the unrealistic "best-case" scenario of 1.5C of warming by 2100, many millions of people will have to choose between starvation and migration, Philip Alston, the UN Special Rapporteur on extreme poverty and human rights warned.

He predicted a split between those able to mitigate the worst effects of the warming planet and those with no means to avoid it, calling it a "climate apartheid".

And he said the fallout from our rapidly warming climate would have dire implications for human rights and democracy.

"What was once considered catastrophic warming now seems like a best-case scenario," Mr Alston said.

Coral reefs: Trying to combat climate change damage Show all 25 1 /25 Coral reefs: Trying to combat climate change damage Coral reefs: Trying to combat climate change damage Masked Butterflyfish (Chaetodon semilarvatus) swimming over a bommie reef in the Egyptian Red Sea marine reserve of Ras Mohamed, off the southern tip of the Sinai peninsula AFP/Getty Coral reefs: Trying to combat climate change damage Rising sea temperatures cause corals to bleach (go white) and die Getty/iStock Coral reefs: Trying to combat climate change damage A giant clam is seen nestled among coral reefs at the Obhor coast, 30 kms north of the Red Sea city of Jeddah AFP/Gett Coral reefs: Trying to combat climate change damage Coral reef in seychelles that has degraded After the reef has died they break up and become rubble. On this reef there is some regrowth of young corals so there is hope for recovery Getty Coral reefs: Trying to combat climate change damage Coral gardening A rabbitfish in a net H Goehlich Coral reefs: Trying to combat climate change damage A school of fish and a sea can in a healthy coral reef off the coast of Isla Mujeres, Mexico Getty/Lumix Coral reefs: Trying to combat climate change damage Sky views of great barrier reef in Australia Getty/iStock Coral reefs: Trying to combat climate change damage A fish swims among coral reefs at the Obhor coast AFP/Getty Coral reefs: Trying to combat climate change damage Researchers from the Interuniversity Institute for Marine Sciences in the southern Israeli resort city Eilat monitor coral growth while scuba diving in the Red Sea AFP/Getty Coral reefs: Trying to combat climate change damage Coral gardening A rope nursery Nature Seychelles Coral reefs: Trying to combat climate change damage Fish swimming off the coast of Egypt's Red Sea resort of Hurghada. The rebounding tourism sector is worrisome for the fragile marine ecosystem AFP/Getty Coral reefs: Trying to combat climate change damage Coral gardening A parrotfish on the reef C Reveret Coral reefs: Trying to combat climate change damage Gorgonian sea fan on a a coral reef in the Egyptian Red Sea marine reserve of Ras Mohamed AFP/Getty Coral reefs: Trying to combat climate change damage A diver swims during a Great Barrier Reef experience on Lady Elliot Island, Australia Getty/Tourism Queensland Coral reefs: Trying to combat climate change damage Jessica Bellsworthy, a PhD student conducting research on the coral reefs of the Gulf of Eilat, holds a coral in an aquarium at the Interuniversity Institute for Marine Sciences in Eilat AFP/Getty Coral reefs: Trying to combat climate change damage Coral reefs in the water off the Obhor coast, 30 kms north of the Red Sea city of Jeddah in 2008 AFP/Getty Coral reefs: Trying to combat climate change damage A diver photographs golden anthias (Pseudanthias aurulentus) on a coral reef in the Egyptian Red Sea marine reserve of Ras Mohamed AFP/Getty Coral reefs: Trying to combat climate change damage FUNAFUTI, TUVALU - AUGUST 15: From the air the ocean (L) and the logoon (R) and separated by a thin stip of land on August 15, 2018 in Funafuti, Tuvalu. The small South Pacific island nation of Tuvalu is striving to mitigate the effects of climate change. Rising sea levels of 5mm per year since 1993, well above the global average, are damaging vital crops and causing flooding in the low lying nation at high tides. Sea water rises through the coral atoll on the mainland of Funafuti and inundates taro plantations, floods either side of the airport runway and affects peoples homes. The nation of 8 inhabited islands with an average elevation of only 2m above sea level is focusing on projects to help it and its people have a future. Four of the outer islands are 97% solar energy dependent and the Tuvalu Government is working to achieve 100% renewable energy from wind and solar by 2025. Tuvalu's 11,000 inhabitants see the effects of climate change in their daily life. (Photo by Fiona Goodall/Getty Images for Lumix) Fiona Goodall Getty/Lumix Coral reefs: Trying to combat climate change damage A photo taken on April 4, 2019 shows fish swimming off the coast of Egypt's Red Sea resort of Hurghada. - In dazzling turquoise waters off Egypt's Red Sea coast, scuba divers swim among delicate pink jellyfish and admire coral -- but the rebounding tourism sector is worrisome for the fragile marine ecosystem. (Photo by Mohamed el-Shahed / AFP) (Photo credit should read MOHAMED EL-SHAHED/AFP/Getty Images) MOHAMED EL-SHAHED AFP/Getty Coral reefs: Trying to combat climate change damage Coral gardening A damselfish Sarah Frias-Torres Coral reefs: Trying to combat climate change damage Divers swim past a coral reef in the Egyptian Red Sea marine reserve AFP/Getty Coral reefs: Trying to combat climate change damage A puffer fish hovering above coral in the Egyptian Red Sea marine reserve AFP/Getty Coral reefs: Trying to combat climate change damage Researchers from the Interuniversity Institute for Marine Sciences in the southern Israeli resort city Eilat monitor coral growth while scuba diving on June 12, 2017 in the Red Sea off Eilat. Global warming has in recent years caused colourful coral reefs to bleach and die around the world -- but not in the Gulf of Eilat, or Aqaba, part of the northern Red Sea. At the Interuniversity Institute for Marine Sciences in southern Israeli resort city Eilat, dozens of aquariums have been lined up in rows just off the Red Sea shore containing samples of local corals AFP/Getty Coral reefs: Trying to combat climate change damage This photo taken on April 21, 2017 shows an aerial shot of part of mischief reef in the disputed Spratly islands on April 21, 2017. Philippine Defence Secretary Delfin Lorenzana flew to a disputed South China Sea island on April 21, brushing off a challenge by the Chinese military while asserting Manila's territorial claim to the strategic region. / AFP PHOTO / TED ALJIBE (Photo credit should read TED ALJIBE/AFP/Getty Images) TED ALJIBE AFP/Getty Coral reefs: Trying to combat climate change damage fish swimming off the coast of Egypt's Red Sea resort of Hurghada AFP/Getty

"While people in poverty are responsible for just a fraction of global emissions, they will bear the brunt of climate change, and have the least capacity to protect themselves.

“We risk a ‘climate apartheid’ scenario where the wealthy pay to escape overheating, hunger, and conflict while the rest of the world is left to suffer.

"Climate change is, among other things, an unconscionable assault on the poor."

He cited vulnerable New Yorkers being stranded without power or healthcare when Hurricane Sandy hit in 2012, while "the Goldman Sachs headquarters was protected by tens of thousands of its own sandbags and power from its generator".

The poorest half of the world’s population – 3.5 billion people – is responsible for just 10 per cent of carbon emissions, while the richest 10 per cent are responsible for around half of greenhouse gases.

And a person in the wealthiest 1 per cent uses 175 times more carbon than one in the bottom 10 per cent, an Oxfam report from 2015 found.

There have been some positive developments, with renewable energy prices falling, coal becoming uncompetitive, emissions declining in 49 countries, and 7,000 cities, 245 regions, and 6,000 companies committing to climate mitigation.

Donald Trump on his discussion with Prince Charles on climate change, and whether he believes in it

However, despite ending its reliance on coal, China – the world's biggest polluter – is still exporting coal-fired power plants and is failing to crack down on its own methane emissions.

Meanwhile Brazil's Jair Bolsonaro plans to open up the Amazon rainforest for mining, end demarcation of indigenous lands, and weaken environmental protection.

Donald Trump has blamed other nations for the crisis despite the US being the world's second biggest polluter.

“China, India, Russia, many other nations, they have not very good air, not very good water, and the sense of pollution. If you go to certain cities … you can’t even breathe, and now that air is going up … They don’t do the responsibility," he said in an interview earlier in June.

Mr Alston also criticised the "patently inadequate" steps taken by UN human rights bodies to address the climate crisis, saying the "incremental" progress was "entirely disproportionate to the urgency and magnitude of the threat".