CLIMATE change will fundamentally reshape life on Earth in the coming decades, even if humans can tame planet-warming greenhouse gas emissions, according to a landmark draft report from the United Nations’ climate science advisors obtained by Agence France-Presse.

Species extinction, more widespread disease, unliveable heat, ecosystem collapse, cities menaced by rising seas — these and other devastating climate impacts are accelerating and bound to become painfully obvious before a child born today turns 30.

The choices societies make now will determine whether our species thrives or simply survives as the 21st century unfolds, the Intergovernmental Panel on Climate Change (IPCC) said.

But dangerous thresholds are closer than once thought and dire consequences stemming from decades of unbridled carbon pollution are unavoidable in the short term.

“The worst is yet to come, affecting our children’s and grandchildren’s lives much more than our own,” the report says.

The document, designed to influence critical policy decisions, is not scheduled for release until February 2022 — too late for crunch UN summits this year on climate, biodiversity and food systems, some scientists say.

The draft report comes at a time of global “eco-awakening” and serves as a reality check against a slew of ill-defined net-zero promises by governments and corporations worldwide.

The challenges it highlights are systemic, woven into the very fabric of daily life.

They are also deeply unfair: those least responsible for global warming will suffer disproportionately, the report makes clear.

It warns that previous major climate shocks dramatically altered the environment and wiped out most species, raising the question of whether humanity is sowing the seeds of its own demise.

“Life on Earth can recover from a drastic climate shift by evolving into new species and creating new ecosystems,” it said. “Humans cannot.”

There are at least four main takeaways in the draft report, which may be subject to minor changes in the coming months as the IPCC shifts its focus to a key executive summary for policymakers.

The first is that with 1.1 degrees Celsius of warming clocked so far, the climate is already changing.

A decade ago, scientists believed that limiting global warming to 2 degrees Celsius above mid-19th century levels would be enough to safeguard our future.

On current trends, we’re heading for 3 degrees Celsius at best.

Earlier models predicted we were not likely to see Earth-altering climate change before 2100.

But the UN draft report said that prolonged warming even beyond 1.5 degrees Celsius could produce “progressively serious, centuries’ long and, in some cases, irreversible consequences.”

Last month, the World Meteorological Organization projected a 40-percent chance that Earth will cross the 1.5-degree threshold for at least one year by 2026.

For some plants and animals, it could be too late.

Indigenous populations in the Arctic face cultural extinction as the environment upon which their livelihoods and history are built melts beneath their snowshoes.

The world must face up to this reality and prepare for the onslaught — a second major takeaway of the report.

“Current levels of adaptation will be inadequate to respond to future climate risks,” it cautions.

Mid-century projections — even under an optimistic scenario of 2 degrees Celsius of warming — make this an understatement.

Tens of millions more people are likely to face chronic hunger by 2050 and 130 million more could experience extreme poverty within a decade if inequality is allowed to deepen.

In 2050, coastal cities on the “frontline” of the climate crisis will see hundreds of millions of people at risk from floods and increasingly frequent storm surges made more deadly by rising seas.

Some 350 million more people living in urban areas will be exposed to water scarcity from severe droughts at 1.5 degrees Celsius of warming — 410 million at 2 degrees Celsius.

That extra half-a-degree will also mean 420 million more people exposed to extreme and potentially lethal heatwaves.

“Adaptation costs for Africa are projected to increase by tens of billions of dollars per year with warming greater than 2 degrees,” the report cautions.

Point of no return

Thirdly, the report outlines the danger of compound and cascading impacts, along with point-of-no-return thresholds in the climate system known as tipping points, which scientists have barely begun to measure and understand.

A dozen temperature trip wires have now been identified in the climate system for irreversible and potentially catastrophic change.

Recent research has shown that warming of 2 degrees Celsius could push the melting of ice sheets atop Greenland and the West Antarctic — with enough frozen water to lift oceans 13 meters (43 feet) — past a point of no return.

Other tipping points could see the Amazon basin morph from tropical forest to savannah and billions of tons of carbon leech from Siberia’s permafrost, fueling further warming.

In the more immediate future, some regions — eastern Brazil, Southeast Asia, the Mediterranean, central China — and coastlines almost everywhere could be battered by multiple climate calamities at once: drought, heatwaves, cyclones, wildfires and floods.

But global warming impacts are also amplified by all the other ways that humanity has shattered Earth’s equilibrium.

These include “losses of habitat and resilience, overexploitation, water extraction, pollution, invasive nonnative species and dispersal of pests and diseases,” the report said.