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By Roger Highfield on

Scientists issue ‘final warning’ in IPCC report

Roger Highfield, Science Director, discusses today’s landmark IPCC report on the climate crisis, a ‘final warning’ from scientists: act now or it will be too late.

A report published today (20 March) by the Intergovernmental Panel on Climate Change, IPCC, ‘is a survival guide for humanity,’ according to António Guterres, Secretary-General of the United Nations.

The report for the IPCC, the UN body for assessing the science related to climate change, took hundreds of scientists around eight years to compile and runs to thousands of pages.

It marks ‘a clarion call to massively fast-track climate efforts by every country and every sector and on every timeframe,’ Guterres added. ‘Our world needs climate action on all fronts: everything, everywhere, all at once.’

‘The report offers hope, but it also offers a warning’ noted Hoesung Lee, Chairperson of the Intergovernmental Panel on Climate Change, at a press conference. ‘There is insufficient action on climate change. We are walking when we should be sprinting.’

‘Those who have contributed the least to climate change are often most vulnerable to its impacts,’ he added.

‘Climate justice is crucial because those who have contributed least to climate change are being disproportionately affected,’ said Aditi Mukherji, one of the 93 authors.

‘The 10% highest-emitting households contribute about 40% of global greenhouse gas emissions,’ commented Prof Daniela Schmidt, Professor in Earth Sciences, University of Bristol. ‘The poorest 50% contribute only a fraction but will experience hunger, droughts and floods if we do not dramatically reduce emissions.’

There are many, feasible and effective options to reduce greenhouse gas emissions and adapt to human-caused climate change that are already available, said the latest report.

The report makes clear that responsible methods to remove carbon dioxide from the air, as highlighted in a recent Science Museum exhibition, Our Future Planet, is not just an option but a necessity to speed up mitigation. This could also counterbalance leftover emissions from hard-to-abate sectors such as aviation and agriculture, or reduce the global temperature in the case of overshooting the current target of 1.5 degrees, which will be reached in the first half of the next decade.

Dr Chris Jones, Met Office Hadley Centre, member of the report’s core writing team, said ‘Renewed efforts to invest in sustainable development give us the best chance of a climate-resilient future.’

‘Time has run out to act’, said Prof Pierre Friedlingstein, Chair in Mathematical Modelling of Climate Systems at the University of Exeter. ‘To me, the one single sentence from the report that says it all is the following: “The choices and actions implemented in this decade will have impacts now and for thousands of years.”’

Today’s report is the final part of the IPCC’s Sixth Assessment Report (AR6) and synthesises the efforts of three working groups of the IPCC and three special reports (Global Warming of 1.5°C, Climate Change and Land, and on the Ocean and the Cryosphere in a Changing Climate).

‘This comprehensive synthesis of the state of knowledge on climate science assessed by many hundreds of scientists across three weighty reports is clear that greenhouse gas emissions must be rapidly cut across all sectors of society until net emissions are zero’, commented Prof Richard Allan, Professor of Climate Science, University of Reading.

Earlier reports included warnings that the world was approaching ‘irreversible’ levels of global heating, with catastrophic impacts rapidly becoming inevitable; and that it was ‘now or never’ to take drastic action to avoid a climate disaster.

In 2018, the IPCC said that emissions must be halved by 2030, compared with 2010 levels, to have a good chance of limiting temperature rises to 1.5C, as outlined in the Paris Agreement.  But this would only deliver a 50:50 chance of keeping the most ambitious pledge of the Paris Agreement alive, says the Met Office.

‘The release of the report couldn’t be more timely, as the UN is currently evaluating the adequacy of climate action under the Paris Agreement,’ commented Prof Joeri Rogelj, Professor of Climate Science & Policy, Imperial College London.

Today’s report is supposed to inform the next UN climate summit, COP28, which will be hosted by the United Arab Emirates in Dubai from 30 November.

The next report of this magnitude will not appear until around 2030, so today’s AR6 is the last IPCC report while it is still feasible – only just – to stay within 1.5C.

Prof Bill Collins, Professor of Climate Processes, University of Reading, commented: ‘Time is running out. How much fossil fuel we burn this decade will determine whether warming can be limited to 1.5 or 2 degrees. The time is now to decide whether or not to take the sustainable path set out by the IPCC.’