PARIS: Climate change will fundamentally reshape life on the planet in the coming decades, even if humans can tame planet-warming greenhouse gas emissions, according to a landmark draft report from the UN’s climate science advisers.

Species extinction, more widespread disease, extreme 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) says in a draft report seen exclusively by AFP.

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. By far the most comprehensive catalogue ever assembled of how climate change is upending our world, the report reads like a 4,000-page indictment of humanity’s stewardship of the planet.

But 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.

In response to AFP’s reporting, the IPCC released a statement saying it “does not comment on the contents of draft reports while work is still ongoing”.

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.

And it shows that even as we spew record amounts of greenhouse gases into the atmosphere, we are undermining the capacity of forests and oceans to absorb them, turning our greatest natural allies in the fight against warming into enemies.

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 says. “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 two degrees Celsius above mid-19th century levels would be enough to safeguard our future. That goal is enshrined in the 2015 Paris Agreement, adopted by nearly 200 nations who vowed to collectively cap warming at “well below” two degrees Celsius — and 1.5 degrees if possible.

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

Earlier models predicted we were not likely to see Earth-altering climate change before 2100. But the UN draft report says 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 Organisation projected a 40 per cent 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. “Even at 1.5 degrees Celsius of warming, conditions will change beyond many organisms’ ability to adapt,” the report notes.

Published in Dawn, June 24th, 2021