PARIS: The same oceans that nourished human evolution are poised to unleash misery on a global scale unless the carbon pollution destabilising Earth’s marine environment is brought to heel, warns a draft UN report.

Destructive changes already set in motion could see a steady decline in fish stocks, a hundred-fold or more increase in the damage caused by superstorms, and hundreds of millions of people displaced by rising seas, according to the Intergovernmental Panel on Climate Change (IPCC) “special report” on oceans and Earth’s frozen zones, known as the cryosphere.

As the 21st century unfolds, melting glaciers will first give too much and then too little to billions who depend on them for fresh water, it finds.

Without deep cuts to manmade emissions, at least 30 per cent of the northern hemisphere’s surface permafrost could melt by century’s end, unleashing billions of tonnes of carbon and accelerating global warming even more.

The 900-page scientific assessment is the fourth such tome from the United Nations in less than a year, with others focused on a 1.5-Celsius cap on global warming, the state of biodiversity, and how to manage forests and the global food system.

All four conclude that humanity must overhaul the way it produces and consumes almost everything to avoid the worst ravages of climate change and environmental degradation.

Governments meet in Monaco next month to vet the new report’s official summary. While the underlying science — drawn from thousands of peer-reviewed studies — cannot be modified, diplomats with scientists at their elbow will tussle over how to frame the findings, and what to leave in or out.

The final advice to policymakers will be released on Sept 25, too late to be considered by world leaders gathering two days earlier for a summit convened by UN Secretary-General Antonio Guterres to extract stronger national commitments in confronting the climate crisis.

Guterres may be disappointed by what the world’s major greenhouse gas emitters put on the table, according to experts tracking climate politics in China, the United States, the European Union and India.

The Big Four — accounting for nearly 60 per cent of global fossil fuel-based emissions — all face devastating ocean- and ice-related impacts, but none seems prepared to announce more ambitious goals for purging carbon from their economies.

These nations face many of the threats outlined in the IPCC report. Shanghai, Ningbo, Taizhou and another half-dozen major coastal cities in China, for example, are highly vulnerable to future sea level rise, which is projected to add a metre by 2100 compared to the late 20th century global watermark, if CO2 emissions continue unabated. Mumbai and other coastal Indian cities are in harm’s way as well.

Published in Dawn, August 30th, 2019