Capping global temperature rise at two degrees Celsius over baseline is no longer seen as enough to avoid a catastrophic rise in sea levels that would decimate the earth’s coastlines and displace hundreds of millions of people, climate scientists warn.
A report released Thursday by the International Cryosphere Climate Initiative, compiled by more than 60 scientists and policy experts, is sounding the alarm on new modelling data that indicates the 2015 Paris Agreement is woefully out-of-date.
The consortium is urging world leaders to take stock of new research ahead of the United Nations’ COP28 climate conference later this month. According to the report, the only road forward is ensuring that global temperatures do not rise over 1.5C above pre-industrial levels, much lower than the two degree maximum set at the Paris Climate Accords.
“We have time, but not much time,” reads the report’s preface, written by the president of Chile and prime minister of Iceland. “We cannot negotiate with the melting point of ice.”
If global average temperatures rise by two degrees, the Earth faces a sea-level rise of more than 12 metres, or 40 feet — and that’s the conservative estimate.
The report states sea levels could rise up to 20 metres, or 65 feet, citing a “compelling number of new studies, taking into account ice dynamics, paleo-climate records from Earth’s past, and recent observations of ice sheet behavior.”
If this is allowed to happen, the planet faces “extensive coastal loss and damage well beyond limits of feasible adaption,” the report warns.
This melt would take place over decades, even centuries, but would result in a dramatic reshaping of the earth’s coastlines.
During a February meeting at the UN, Secretary-General Antonio Guterres said sea levels rising will cause a “mass exodus of entire populations on a biblical scale,” noting that 900 million people — representing 10 per cent of the world’s population — live in low-lying coastal areas.
And that prediction of a 12-20 metre rise in sea levels was modelled based on the already far-fetched hope that the world can cap warming at two degrees.
According to the UN Framework Convention on Climate Change, which organizes the COP climate conferences, the world is on track to warm by 2.5 degrees Celsius above pre-industrial levels by the end of the century.
Even if humanity were to somehow reverse this warming down the line, sea levels would continue to rise, the report warns.
“Many ice sheet scientists now believe that by 2°C, nearly all of Greenland, much of West Antarctica, and even vulnerable portions of East Antarctica will face very long-term, inexorable sea-level rise, even if air temperatures later decrease. This is due to a warmer ocean that will hold heat longer than the atmosphere,” the report reads.
Melting glaciers and permafrost were also flagged as areas of concern in the report, with scientists warning that some glaciers “will disappear, some as early as 2050,” projections show.
“Other (glaciers) are large enough to delay complete loss until the next century, but have already passed a point of no return. Even the Himalayas are projected to lose around 50% of today’s ice at 2°C.”
And as permafrost around the world also melts, it releases carbon dioxide and other greenhouse gases trapped within that further exacerbate global warming.
At 2C warming, “these emissions are irreversibly set in motion and will not slow for one-to-two centuries,” the report reads, adding that even 1.5C warming could even be “too high to prevent extensive permafrost thaw.”
In order to keep emissions from the melting permafrost in check, future generations will have to offset them with carbon capture, the report says.
The report’s findings add to a growing air of urgency surrounding the climate crisis, and what steps will be necessary to avoid catastrophic effects.
Current national climate plans submitted to UN Climate Change would put 2030 carbon emissions at just two per cent below 2019 levels. To achieve 1.5C warming, the world would need to reduce carbon emissions by 43 per cent.
“The downward trend in emissions expected by 2030 shows that nations have made some progress this year,” said Simon Stiell, Executive Secretary of UN Climate Change.
“But the science is clear and so are our climate goals under the Paris Agreement. We are still nowhere near the scale and pace of emission reductions required to put us on track toward a 1.5 degrees Celsius world. To keep this goal alive, national governments need to strengthen their climate action plans now and implement them in the next eight years.”