As many as 3.6 billion people are now living in 'highly vulnerable' contexts

Up to 3.6 billion people live in contexts that are highly vulnerable to climate change, the United Nations has said in a new report that found numerous species are moving toward the poles and to higher elevations because of the impact of global warming.

In its latest report, the UN's Intergovernmental Panel on Climate Change, or IPCC, said climate change is causing "dangerous and widespread disruption" in nature and is affecting billions of people around the world, despite efforts to reduce the risks.

People and ecosystems least able to cope are being hardest hit, said IPCC chairman Hoesung Lee.

"This report is a dire warning about the consequences of inaction," said Lee. "It shows that climate change is a grave and mounting threat to our wellbeing and a healthy planet. Our actions today will shape how people adapt and nature responds to increasing climate risks."

The IPCC said that approximately 3.3 to 3.6 billion people now live in contexts that are "highly vulnerable to climate change".

Responding to the report, United Kingdom-based charity Oxfam said "inequality is at the heart of today's climate crisis" and said that rich countries have not done enough to support developing regions.

At the COP26 climate change conference in Glasgow last year, delegates agreed to double adaptation finance to $40 billion by 2025, though Oxfam said that this is "nowhere near enough.

"The UN estimates that developing countries need $70 billion every year to adapt, and those costs are not falling," Oxfam said in a statement.

"Rich countries are overwhelmingly responsible for the climate crisis and must do more to support the poorest communities whose citizens struggle to meet their daily needs, let alone prepare for the future."

Swenja Surminski, head of adaptation research at the London School of Economics' Grantham Research Institute on Climate Change and the Environment, said that adaptation finance "is not a cost, it is an investment.

"Investing in adaptation and resilience is crucial, and it needs to happen now," said Surminski, who was not involved in the report.

"Every dollar invested in adaptation today will save at least five dollars' worth of loss and damage in future."

The new study is the second part of the sixth assessment report from the IPCC. The first part, released in August, looked at the physical science basis for climate change. This latest installment, involving 270 authors from 67 countries, puts forth the latest evidence on the impacts of climate change and the ways of adapting to them.

The authors paint a grim picture, warning that extreme weather events, including droughts, floods and heatwaves, are all accelerating and causing increasing damage. The study also highlighted the impact of climate change on other species.

"Approximately half of the species assessed globally have shifted polewards or, on land, also to higher elevations," the IPCC said. "Hundreds of local losses of species have been driven by increases in the magnitude of heat extremes, as well as mass mortality events on land and in the ocean."

Bob Ward, policy director at the Grantham Research Institute, called the report a "shocking catalog of the already significant and growing harm" to lives and livelihoods across the world from climate change impacts.